Agricultural wastes: A practical and potential source for the isolation and preparation of cellulose and application in agriculture and different industries

Cellulose is an organic compound belonging to polysaccharides. This biopolymer is made of glucose subunits. This compound plays an essential role in the structure and strength of plants. This polymer has biodegradable, biocompatible, and renewable properties. Agricultural wastes are excellent sources for cellulose extraction. Agricultural wastes are lignocellulosic materials

Agricultural wastes are generated rapidly with an average annual increase rate of 5-10%, which leads to adverse environmental effects, as burning such wastes leads to water, soil, and air pollution (Debnath et al., 2021).With the increase in the production of agricultural products, millions of tons of agricultural waste are produced.According to other reports, about 731 MT, 354 MT, 203 MT, and 180 MT are produced for rice straw, wheat straw, corn straw, and bagasse, respectively.Among these, the Asia mainland produces the most quantity of rice straw.Fruit waste and skin are other materials that increase agricultural waste production.Disposing of these wastes, in addition to producing leachate, produces a lot of fuel energy.Burning the remains of the product produces large amounts of greenhouse gases, pollutants, and suspended particles.Therefore, there is a need for sustainable management of these wastes (Binod et al., 2010;de de de Moraes Rocha et al., 2015;Li and Chen, 2020;Schiopu and Gavrilescu, 2010).
Agricultural and industrial wastes have many valuable elements that can be extracted and included in producing many materials.Cellulose is one of the elements that can be produced from these wastes (Rao et al., 2023).
Agricultural wastes are lignocellulosic materials; cellulose and lignin are the main components of these wastes (Ates et al., 2020;Singha et al., 2009).Upgrading such waste by developing innovative products such as cellulose nanomaterials and nanocomposites can have high environmental and economic benefits (Uddin and Haque, 2023) (Pandele et al., 2017).Most biomass wastes contain significant amounts of cellulose, which form the basis of cellulose nanocrystals.Nanocrystals synthesized from agricultural waste are widely used in various fields due to their renewable nature, excellent biocompatibility, specific surface area, and high tensile strength.Cellulose can be produced from biomass waste through acid hydrolysis, enzymatic hydrolysis, oxidation hydrolysis, and other mechanical methods (Liu et al., 2023).Different agricultural sources can be considered sources of cellulose waste (Arévalo Gallegos et al., 2016).Fig. 1 depicts several sources of agricultural waste.Since about 32-65% of agricultural waste is composed of cellulose materials, and cellulose as a biopolymer plays an essential role in sustainable agriculture, it is possible to extract cellulose with various methods to use it in various industries, especially in agriculture, medicine, and food packaging (Li and Chen, 2020).Due to strong hydrogen bonding networks, cellulose is insoluble (in water and other organic solvents).Also, the hydroxyl groups in cellulose have made it a natural raw material for superabsorbent hydrogels (Das et al., 2021;Hasan and Abdel-Raouf, 2019;Liu et al., 2019;Salleh et al., 2018).Various mechanical, chemical and biological processes are carried out to extract cellulose from agricultural waste and remove non-cellulosic components.Super absorbent hydrogels are one of the applications of extracted cellulose fiber (Kabiri et al., 2011).
The increase in agricultural production after harvest in the fields produces a large amount of agricultural waste.A significant amount of these wastes are in the form of rice, wheat, and corn straw in the fields, which are not used.Finally, local farmers burn most of these wastes in an Fig. 1.Diverse agricultural wastes for cellulose synthesis.R.S. Riseh et al. open space, producing a large amount of smoke that severely affects human health and the environment.Most farmers are unaware of the value of waste recycling and its economic potential.Most of the agricultural waste consists of lignocellulosic materials, especially cellulose, hemicellulose and lignin (Mussatto et al., 2012;Romruen et al., 2022;Shehrawat and Sindhu, 2015).The correct management of agricultural waste leads to the reduction of environmental pollution.Also, cellulose extracted in this way can be used in most industrial, agricultural, and medical activities.
Only 10% of agricultural wastes containing cellulose are used to produce valuable items, such as biocomposites, automotive components, and biomedical components (Dungani et al., 2016).Agricultural wastes, called cellulosic fibers (CFs), are the most abundant renewable organic material produced in the biosphere (Habibi et al., 2010).Cellulose is generally distributed in higher plants, most aquatic species (e. g., tunicates), algae, fungi, bacteria, invertebrates, and even amoebae (e. g., Dictyostelium discoideum) to a lesser extent.In general, cellulose, a fibrous material, plays an important role in maintaining the structure of plant cell walls (Habibi et al., 2010).Compared to hardwood materials, cellulose is cost-effective, lightweight, stable, degradable, and soft.Wood, the most important lignocellulosic fiber, is the primary source of cellulose in forests (Figueiredo et al., 2010;Kalia, 2017;Li et al., 2021;Pennells et al., 2020;Rani et al., 2014;Zhao et al., 2021;Zhou et al., 2022).Nanocellulose extracted from agricultural wastes can be chemically or physically processed to produce high-performance nanocellulose-based superabsorbent hydrogels.Chemical approaches focus on polymerization through the formation of covalent bonds.Physical approaches depend on the molecular assembly connected by hydrogen and/or ionic bonds between biopolymers (Li and Chen, 2020).Biocontrol bacteria are important in inducing plant disease resistance (Baradar et al., 2015;Egamberdieva et al., 2023;Lagzian et al., 2013).Combining biocontrol agents with natural polymers seems to increase the efficiency of biological control bacteria in field conditions (Saberi Riseh et al., 2022b).Cellulose, a natural polymer, can be highly effective with biocontrol agents.
Also, with the rapid increase in population and the industrialization of countries, the demand for energy is increasing.This issue has two significant consequences: 1-reduction of resources (oil, natural gas and coal); 2-Severe ecological pollution due to increased global temperature and ozone.Therefore, agricultural waste can be a suitable and safe alternative to fossil fuels (Kumar et al., 2023;Saleem, 2022;Yana et al., 2022).
Research has also shown that biofuel production, especially from agricultural residues/agricultural wastes, is very beneficial because agricultural residues are cheap, readily available, renewable, and highly biodegradable.Agricultural waste has recently become one of the most popular alternative energy sources for non-renewable and renewable energies.In addition to the economic aspect (low production cost due to cheap materials available) and environmental concern (environmental degradation due to phenolic compounds), agricultural waste can be minimized through its use during biofuel production (Debnath et al., 2021;Samanta et al., 2023).In this article, we reviewed the importance of agricultural wastes as high-efficiency sources for cellulose extraction, the different methods of cellulose extraction from these sources, and the use of cellulose in various industries.
This polymer is a linear, stereo-regular, semi-crystalline polysaccharide composed of D-glucopyranose units ("chair" conformation) linked by chemical β-1,4-glycosidic bonds (Ioelovich, 2014).The repeating unit in glucose is represented as an anhydroglucose unit (AGU) (Lehrhofer et al., 2022).The cellulose's hydroxy groups (OH) formed a strong and complex intermolecular hydrogen bond network.These hydrogen bonding interactions form crystalline and amorphous structures (Nunes, 2017).Due to the presence of many OH in the polymer, this polymer is extensively hydrogen-bonded and has inter-chain and intra-chain bonding.Intra-chain hydrogen bondings are responsible for stabilizing glycosidic bonds, while inter-chain hydrogen bondings are responsible for the parallel stacking of multiple cellulose chains (Parthasarathi et al., 2011).Cellulose with a polymorphic structure has four main allomorph types.The native form of cellulose is cellulose I, which most living organisms synthesize.This type of cellulose consists of Iα/Iβ allomorphs, which differ in crystal packing, molecular structure, and hydrogen bonding.Natural type II cellulose is synthesized by a minimal number of species, most of which are bacteria.This type of cellulose chain is arranged antiparallel with extensive interlamellar OH due to differences in the crystal structure.Type II cellulose has a higher thermodynamic stability than Type I. Cellulose III can be obtained by reacting cellulose I or II with various amines (such as liquid ammonia).When cellulose is treated with glycerol at high temperatures, cellulose IV is obtained (French and Santiago Cintrón, 2013;Lehrhofer et al., 2022;Nunes, 2017).Fig. 3 shows the path of synthesis of different types of cellulose from type I cellulose.

The importance and position of cellulose
Cellulose is the most abundant organic compound in the world, which plants mainly produce (Saberi Riseh et al., 2023e).It is the most structural component in plant cells and tissues.Cellulose offers several important biological roles in plant cell walls, including 1) Mechanical strength of the cell wall, 2) role in plant growth, 3) cell differentiation, 4) Intercellular communication, 5) water transfer, and 6) Defense (Cosgrove, 2005;Rongpipi et al., 2019).The primary plant cell wall has a thin, flexible, and highly hydrated structure surrounding the growing cell.In contrast, the secondary cell wall has a stronger and more rigid structure that starts depositing when the cell stops growing.Primary and secondary cell walls are different in function, rheological, mechanical properties, mobility, and structure of matrix polymers.Primary walls are mainly composed of cellulose, pectin, and xyglucans.While secondary cell walls are primarily composed of cellulose, lignin, xylans, and glucomannan.The strength of this wall is due to the arrangement of more cellulose microfibrils and the presence of lignin (Cosgrove and Jarvis, 2012).
To gain insight into the cellulose from an industrial point of view, it is necessary to extract it through chemical processing.Processed cellulose from carbon disulfide, sulfuric acid, sodium sulfate, and glycerin forms a transparent cellophane film.Cellophane has many uses in pharmaceutical packaging due to its compatibility, durability, transparency, and elasticity (Rongpipi et al., 2019).As a natural polymer, cellulose is widely used in textiles, paper, construction materials, and industrial chemical derivatives.As the most abundant carbohydrate on earth, this polymer is a renewable and biocompatible energy source (Rongpipi et al., 2019).This polymer is used in many industries, including food, veterinary uses, wood, paper, fibers, clothing, cosmetics, health, and pharmaceutical industries.Cellulose ethers and esters are two main groups of cellulose derivatives with different physical-chemical-mechanical properties.These derivatives are widely used in formulations (with long and delayed release properties, long and controlled release matrices, stabilizers and encapsulation, food packaging, film formation, and formulations) are being used.Cellulose ethers are stable against biodegradation, heat, hydrolysis, and oxidation (Liu, Williams, 2002;Shokri and Adibkia, 2013).Cellulose, a carbon-rich resource, has been of interest as a renewable energy source (in the form of direct combustion to electricity generation and the release of carbon from cellulose to produce cellulosic ethanol) (Lim et al., 2012;Naik et al., 2010).Among the important structural properties of cellulose are its crystallite size and crystallinity, which are considerable (Rongpipi et al., 2019).
Due to the functional characteristics, natural availability, and wide range of applications of cellulose, this polymer has a special place among other polymers(A.S. Singha and Thakur, 2009a).Therefore, the extraction of this valuable material from different sources and methods is considered (Singha and Thakur, 2008;A.S. Singha and Thakur, 2009;Thakur et al., 2010).Agricultural wastes as an accessible resource are a promising option in cellulose extraction.In the following, we will introduce this source, the reason for its importance, and the methods of separating cellulose from agricultural wastes.Finally, we will discuss using cellulose extracted from agricultural waste in various industries.

Agricultural wastes as an ideal and available source for cellulose production
Agricultural wastes are unusable materials (solid or liquid) and byproducts of food production processes, such as residues of agricultural products and livestock waste (Dungani et al., 2016;Shehrawat and Sindhu, 2015).To produce a huge wealth of natural plant fibers currently used, using natural fibers extracted from agricultural waste needs more development and attention.Agricultural and industrial wastes are produced in large quantities all over the world.These wastes have harmful effects on the environment due to the presence of strong fibers with a slow decomposition rate.Agricultural waste materials contain cellulose, which can be extracted for many important processes, including the production of bioplastics (Rao et al., 2021).The agricultural waste consists of lignocellulosic materials, such as cellulose, hemicellulose, and lignin (Fig. 4) and a minimal amount of ash and protein (Awogbemi and Von Kallon, 2022;Ge et al., 2021).Due to its easy availability, stability, low density, non-abrasive, and its non-toxic nature, cellulose is often considered a highly compatible source to replace petroleum-based materials (Rana et al., 2023(Rana et al., , 2021)).Cellulose plant resources in the form of agricultural wastes are abundant worldwide and easily available.These resources are almost inexhaustible and cheap, and as a result, it can be said that the cost The production of nano cellulose is relatively low because the main raw material for the production of cellulose is readily available (Ng et al., 2015;Tamilselvi et al., 2019).As the main component of agricultural waste, cellulose is used as a reinforcing material with low density and high mechanical properties (Das et al., 2016)(Amar Singh Singha and Thakur, 2009) (Thakur et al., 2013).Agricultural wastes containing cellulose are endless resources that can be reused in various fields for environmental and economic benefits (Lawson et al., 2022;Li et al., 2018;Miljković et al., 2021;Van de Vyver et al., 2011).
Based on the reports, Fig. 5 shows the percentage of components of agricultural wastes (Antwi et al., 2019;Bonfiglio et al., 2021;Fonseca et al., 2020;Montoya-Rosales et al., 2020;Naik et al., 2021;Pan et al., 2020;Shahzadi et al., 2014;Shi and Liu, 2021;Umagiliyage et al., 2015;Wang et al., 2021;Wang et al., 2020;Ziaei-Rad et al., 2021).As shown in Fig. 5, a large percentage of agricultural waste is cellulose.However, hemicellulose and lignin are also inhibiting factors in cellulose extraction.If they are not removed during cellulose extraction, they reduce the efficiency and effectiveness of the extracted cellulose.Therefore, different methods should be used to remove secondary products from agricultural waste.The following sections are the different cellulose extraction methods and each method's advantages and disadvantages.

The types of fibers, their yield, and applications
Wheat is one of the important human food products.It originates from the Central Asian region, which has 225 million hectares with a global production of 750 million tons.India ranks second with 109.52 million tons of production and has a 13% share in the global wheat basket (Singh et al., 2023).Wheat straw is one of the important sources of cellulose.This resource has three important uses.These applications include 1) Direct combustion for electricity, 2) Fuel ethanol production, and 3) Feed production (Cheng et al., 2020).Wheat straw is being used for biofuel production in eco-friendly processes.Wheat straw can be used as a source of green energy (Singh et al., 2023).Wheat straw is the second largest lignocellulosic material in the world.Wheat straw, compared to other biomass, is relatively less beneficial, but its higher bioethanol potential and production yields (Singh et al., 2023).Rice straw, due to high ash content and low protein content, does not decompose.The main carbohydrate components of rice straw are  hemicellulose, cellulose and lignin of the cell wall.Generally, straw contains 90% cell wall, 3% silica, and 7% extractives (Sashikala and Ong, 2007).Cellulose derived from rice straw can be used as a strong raw material for hydrogels, composites, or carrier materials for slow-release fertilizers, thereby helping to reduce greenhouse gas emissions (Sharma et al., 2023).
Corn stalks are used as rural energy and animal feed.Corn straw is widely used in fertilizer, feed, edible mushrooms, and industrial raw materials (Hu et al., 2014;Ritota and Manzi, 2019;Zárate-Salazar et al., 2020).Corn straw can effectively improve organic matter content, increase soil fertility, and improve soil's physical and chemical properties (Zhang et al., 2019;Zhang et al., 2014).Different researchers have produced superabsorbent hydrogels using cellulose from different sources.These hydrogels are defined as a three-dimensional network of hydrophilic polymers that can absorb and retain a significant amount of water and due to their excellent hydrophilicity, permeability, high compatibility, and low friction coefficient in the pharmaceutical and medical industries., agriculture and food have been used (Chang et al., 2010;de Oliveira et al., 2017;Hebeish et al., 2014;Vecino et al., 2015a;Vecino et al., 2015b).
Sugarcane bagasse is a fibrous material that contains cellulose as its main component.Bagasse is obtained as a type of waste material from the sugar industry and is mainly used in the paper industry.However, different mechanical and chemical treatments can lead to the extraction of cellulose fibers, pure cellulose, cellulose nanofibers and cellulose nanocrystals.These extracted materials have various applications in producing regenerated cellulose fibers and composite materials (Mahmud and Anannya, 2021).Cellulose extracted from agricultural waste has many applications, which are shown in Fig. 6.Agricultural waste is currently used as a raw material for producing compost, fuel, alcohol, and paper.Due to their unique physicochemical properties, cellulose and its derivatives are also used in many industries, such as pharmaceuticals and energy.Cellulose is used as a filler in many products, such as thermoplastics and adhesives (Tamilselvi et al., 2019).Extracted nanocellulose products have been considered as an alternative to fossil fuels due to their biodegradability and extraordinary ability to be used in environmentally friendly applications (Ge et al., 2022;Peter et al., 2022;Swain, 2017;Wasim et al., 2021).
Also, these biopolymers can be applied as compressibility enhancers, gelling agents, thickening and stabilizing agents, fillers in solid dosage forms, the binders in granulation process, as binders in the granulation process, disintegrating agents, and taste masking agents (Fathi et al., 2019;Gupta et al., 2012;Liu et al., 2011;Rojas and Kumar, 2011;Shokri and Adibkia, 2013).Various applications of cellulose extracted from agricultural wastes are explained in Section 6.
As an idea and a clear path, agricultural waste has many applications in various industries, and the importance and attention to these resources can greatly affect developing countries' economies.Agricultural waste is one of the sources that are produced in large quantities every year in all seasons, and the optimal recycling of these materials can lead to increased production and development of various industries.

Cellulose extraction methods from agricultural wastes
Some agricultural wastes are not easily decomposed due to their complex composition and physicochemical structure.Biomass is subjected to different processes and methods to overcome this obstacle.Pretreatment processes are operations performed on biomass and constituents of the biomass (cellulose, hemicellulose, and lignin) that increase conversion efficiency and extraction.
The primary purpose of pre-treatment of agricultural waste and other lignocellulosic biomass is in these cases: 1-To reduce energy consumption;.2-To reduce cost;.3-Sugar formation from biomass.Pre-treatment also ensures the preservation of the produced sugar from degradation and reduces the production of inhibitory products.Common pre-treatment approaches or Cellulose extraction methods include: 1-physical, 2-chemical, 3-biological, 4-physicochemical, and 5-green solvent-based processes (Areepak et al., 2022;Awogbemi and Von Kallon, 2022;Zhang et al., 2021b).

Physical method
Physical methods are used to reduce particle size (in order to increase enzyme, microbe accessibility, and conversion efficiency during processing, reduce cellulose crystallinity, increase conversion efficiency, improve product yield, and improve product yield).The size reduction contributes to cellulose's crystalline nature and increases activity.The physical method also includes the following pre-treatments (Awogbemi and Von Kallon, 2022):

Mechanical pre-treatment
Application of high mechanical force to break the hard structure of lignocellulose by cutting, grinding, crushing, and stirring methods in order to reduce particle size (increasing surface area), lignin content, and degree of polymerization.In addition, mechanical pretreatment ensures better access to chemicals and enzymes for cellulose and hemicellulose (Bai et al., 2018;Dahunsi, 2019).This method is one of the well-known methods that has the capacity to efficiently improve the intrinsic properties of lignocellulosic biomass by reducing their sizes and disrupting their surface configurations, among other methods.Destructuring of biomass using mechanical methods is usually through applying shear and/or compressive forces, which is equally a function of the materials used in the construction of the shredder.In other words, the coarseness or smoothness of the materials used to make the shredder significantly reduces or improves the efficiency of biogas production from lignocellulosic materials (Dahunsi, 2019;Tsapekos et al., 2015;Tsapekos et al., 2017).The advantages of this pretreatment are as follows: no inhibitors produced, simple and easy operation, reduced crystallinity, enhanced enzyme digestibility, increased porosity, biomass size reduction, and low investment.Also, the disadvantages of this pretreatment can be mentioned as follows: high operational costs, costly process, high energy consumption, inability to degrade lignin, need to combine with other pretreatments, and low sugar yield (Awogbemi and Von Kallon, 2022).

Ultrasonic pre-treatment
Producing energetic vibrations and penetrating the crystals of the lignocellulose structure, which leads to the decomposition of waste.The frequency, intensity, and duration of vibrations play a role in waste decomposition (Mankar et al., 2021;Subhedar et al., 2018).Ultrasound increases the digestibility of biomass by disrupting its physical, chemical and biological properties.The degree of decomposition depends on the ultrasonic parameters and the characteristics of the biomass (Pilli et al., 2011).This method has great potential to transform waste from the food and agriculture industry into value-added products (Wu et al., 2022).Ultrasound is a practical approach to cell wall disruption.Cell rupture occurs through acoustic cavitation due to high shear forces, pressures, and local temperature conditions.These conditions cause characteristic changes through changes in particle size (Bhatia et al., 2015;Li et al., 2019;Saha et al., 2011).The advantages of this pretreatment are as follows: low energy utilization, no inhibitor formation, low waste generation, multiple product generation, and intensified processing.Also, the disadvantages of this pretreatment can be mentioned as follows: low selectivity, high energy consumption, energy lost in diluted media, and difficulties in large-scale reactor design (Awogbemi and Von Kallon, 2022).

Microwave pre-treatment
In microwave irradiation, electromagnetic radiation penetrates the biomass matrix and weakens the interaction between the different components of the lignocellulosic biomass (Koul et al., 2022;Pattanaik et al., 2019).As a fast and effective heating source with thermal and non-thermal effects, microwaves can directly interact with materials and thus accelerate chemical, physical, and biological reactions.Microwave irradiation has been successfully used in the pretreatment of various types of biomass, including agricultural residues, woody biomass, grass, energy plants, and industrial waste (Xu, 2015).This method disrupts the resistant structures of the biomass by applying selective heating to the polar fragments in the aquatic environment.Microwaves have advantages in faster energy transfer, controlled heating, shorter residence time, etc. Therefore, microwave pretreatment can significantly reduce the overall biomass pretreatment time and increase efficiency (Agu et al., 2018).The advantages of microwave heating coupled with alkaline pretreatment include reduction of the process energy requirement, rapid and super heating, and low toxic compound formation (Agu et al., 2018).

Chemical method
Chemical methods include using special chemicals such as acids, alkalis, oxidizing agents, and organic solvents to dissolve the crystalline structure of lignocellulose to overcome and dissolve the rigid lignocellulose crystalline structure.Acids, alkalis, oxidation, and organic solvents have been used as chemicals to enlarge the surface and increase the biodegradability of agricultural waste (Awogbemi and Von Kallon, 2022;Paudel et al., 2017).The chemical method has the following pre-treatments (Awogbemi and Von Kallon, 2022):

Alkaline pre-treatment
Alkaline reagents such as NH 4 OH, NH 3 ⋅H 2 O, and Ca(OH) 2 are used in order to liquefy lignin and hemicellulose, reduce crystallinity and cellulose pretreatment and increase conversion efficiency.This economical pre-treatment reduces environmental pollution (Woiciechowski et al., 2020).

Oxidative pre-treatment
In this pretreatment, ozone and hydrogen peroxide (due to their oxidizing properties) break down lignin and hemicellulose and facilitate R.S. Riseh et al. the release of soluble compounds.By decomposing H 2 O 2 into OH -and O 2 -, lignin structure is broken down and prevents the release of inhibitory side products (Putrino et al., 2020;Tan et al., 2021).

Pre-treatment with organic solvent
Organic solvents such as methanol, ethanol, tetrahydrofuran, ethylene glycol, and acetone are effective for breaking the internal bonds of lignin and hemicellulose.Also, HCl and H 2 SO 4 acids and NaOH, NH 3 , and CaCO 3 bases are used as catalysts to accelerate the reaction process (Kumari and Singh, 2018;Mankar et al., 2021).

Biological method
The biological method uses aerobic bacteria, enzymes, or fungi to decompose lignin.This method does not discharge toxic substances into the environment, consumes little energy, and produces few inhibitory compounds (Sindhu et al., 2016).This method significantly increases the use of cellulose by removing lignin (Chen et al., 2017).There are different types of pre-treatments in this method, which include the following (Awogbemi and Von Kallon, 2022):

Fungal pre-treatment
In this method, white rot fungi, brown rot fungi, soft rot fungi, and other fungi are used for decomposition.Fungal pre-treatment does not require the use of any equipment or chemicals.Fungal pre-treatment efficiency is determined by the raw material's water content and particle size, reaction temperature, and retention time (Awogbemi and Von Kallon, 2022;Dias et al., 2010;Tian et al., 2018).

Termites
Termites (as a group of microorganisms) are biological pretreatments due to having lignocellulose-decomposing enzymes.It has been reported that several groups of termites, such as Microcerotermes parvus, Termes hospes, and Nasutitermes ephratae, secrete lignocellulose degrading enzymes to decompose wheat straw.These enzymes are the main precursors of the anaerobic digestion of wheat straw (Dumond et al., 2021).

Microbial consortium pre-treatment
Soil microbes, sewage, and broiler waste are used as pre-treatment agents to decompose cellulose and hemicellulose in agricultural waste (Zhang et al., 2011).

Bacterial pre-treatment
involves using enzyme-producing bacteria to slow down the polymerization of lignocellulose.Cellulolytic bacteria Acetobacter orientalis and Bacillus subtilis have been used for this purpose (Chen et al., 2021;Xu et al., 2018).

Physicochemical methods
To maximize the efficiency of cellulose extraction, the beneficial properties of physical and chemical pretreatments are combined and presented in the form of physicochemical methods.There are different types of these methods, which are explained below (Awogbemi and Von Kallon, 2022):

Steam explosion pre-treatment
Breaking the β-O-4 bond in lignin and destroying the configuration of the biomass cell wall under the reaction conditions of high temperature (160-250 • C) and pressure (0.5 to). 5 MPa) leads to the extraction of cellulose from lignocellulose (Kumar et al., 2020;Rastogi and Shrivastava, 2017).

Alkaline heat pre-treatment
The use of alkaline substances (such as NaOH, NaCO 3, and alkaline peroxide) and high temperature (75-125 • C) are simultaneously used to decompose lignin, reduce the crystallinity of lignocellulose and increase the contact surface of cellulose.High temperature leads to the simultaneous removal of lignin and hemicellulose and increases the content and efficiency of cellulose (Rodrigues et al., 2016).

Ammonia fiber explosion pre-treatment
The synthesis of ammonia and hydrogen-oxygen ions from liquid ammonia at high pressure leads to an increase in temperature and causes the decomposition of ester-ether bonds between lignin and hemicellulose in synthesized cellulose crystals (Zhao et al., 2020).

Extrusion pre-treatment
Extrusion pre-treatment integrates thermal and mechanical pretreatment methods to change lignocellulose's physical and chemical structure.Agricultural waste is placed in a completely closed environment, and applying much force increases temperature and pressure.Therefore, increasing the temperature and pressure changes the physical and chemical structure of lignocellulosic materials.Adding NaOH to the extrusion process improves the removal efficiency of hemicellulose and lignin (Sankaran et al., 2020;Wang et al., 2019).

Green solvent-based methods
Green solvent-based methods have been expanded due to reduced energy consumption, reduced use of chemicals and toxic materials, less waste generation, and a milder reaction (Roy et al., 2020).This method has the following types of pre-treatments:

Biochemical pre-treatment
In order to compensate for the low efficiency and long retention time associated with biological pretreatment, as well as the large volume of chemicals and the production of inhibitory compounds in chemical pretreatment, biochemical pretreatment methods were presented (Zhao et al., 2022).

Ionic liquid pre-treatment
Ionic liquids are molten salts or liquid electrolytes.Molten salts such as imidazole, pyridine, and choline cations and liquid electrolytes such as chloride and acetate ions are formed, which are liquid at or below room temperature (Roy et al., 2020), interact with lignocellulosic materials, leading to the breaking of β-O-4 bonds.The formation of ionic dipolar bonds in lignin.This process disrupts the synthesis of lignocellulose crystalline composite, the breakdown of lignin structure, and the subsequent separation of lignin and hemicellulose from cellulose-rich materials.(Usmani et al., 2020;Zhang et al., 2021a).

Deep eutectic solvents
These pretreatments have physical and chemical properties and environmentally friendly alternatives.Urea compounds, amides, alcohols, and acids act as hydrogen bond donors, and choline chloride, betaine, and alanine compounds act as hydrogen bond acceptors (Ma et al., 2021;Sarmad et al., 2017).The catalytic combination created from the interface of hydrogen bond donors and acceptors with acidic or basic structure leads to the breaking of the bond between lignin and hemicellulose during pretreatment (Awogbemi and Von Kallon, 2022).

Supercritical fluid
These pretreatments include H 2 O, CO 2 , which behave like liquids at critical temperatures (304.25 k) and 7.36 MPa pressure.Cheap, liquid, high safety, non-toxic, non-flammable, compatible with the environment, and renewable are the characteristics of these pretreatments.By dissolving lignocellulose in a carbon dioxide solution, the chemical bonds between lignin and hemicellulose are broken (Roy et al., 2020).

The comparison of different extraction techniques
In the previous sections, we explained the different methods of extracting cellulose from agricultural waste.However, the question that is raised is which method can be used with the lowest cost and the highest efficiency in extracting cellulose?
Cellulose production from agricultural waste can become a source of income for developing countries, and this is realized by choosing the best extraction method.This section compares these methods and chooses the best and most economical method.
One of the problems of cellulose extraction is that not all the methods and processes are eco-friendly (Magalhães et al., 2023).The selection of the most efficient method depends on the source and desired properties of the final product.Acidic hydrolysis by sulfuric acid is the most widely used extraction method due to its simplicity and the creation of nanoparticles with nanometer size (100-1000) and high crystallinity and hardness.However the long time and waste of organic materials and environmental pollution are the limitations of these methods (Wahib et al., 2022).Sulfuric acid is usually used for hydrolysis as a month with low cost and better stability.But discharging large amounts of acid and taking a long time is one of the drawbacks of using sulfuric acid (Gao et al., 2020;Tang et al., 2015).
Many microorganisms in nature can attack and degrade lignin, thus making access to cellulose easy.These microorganisms possess enzyme systems to attack, depolymerize, and degrade the polymers in lignocellulosic substrates.These pretreatments are mild, economical, and environment friendly (Saritha et al., 2012).
However biological pretreatment processes are mild and environmentally friendly.They use microorganisms, mainly white and soft-rot fungi, actinomycetes, and bacteria that degrade lignin, the most resistant polymer in biomass, through the action of lignin-degrading enzymes such as peroxidases and laccases.Fungi degrade lignin anaerobically through the use of a family of extracellular enzymes collectively termed ligases.Two families of lignolytic enzymes broadly play a key role in enzymatic degradation: phenol oxidase (laccase) and peroxidases (Kirk and Farrell, 1987).In bio-pulping, where lignocellulolytic enzymes were used, the tensile, tearing and bursting indices of the resulting paper were improved, and the brightness of the paper pulp was increased by saving energy by 30-38%.Recent studies have shown that fungal pretreatment of wheat straw for 10 days with a fungal isolate with high lignin decomposition and low cellulose production leads to a decrease in the acid load for hydrolysis, an increase in the release of fermentable sugars, and an increase in reducing the concentration of fermentation inhibitors.The ethanol yield and volume productivity of treated wheat straw were higher than those of untreated wheat straw (Howard et al., 2003;Kuhar et al., 2008;Scott et al., 1998).Rot fungi and actinomycetes can be used to remove lignin from lignocellulosic substrates.Genetic modification to develop high cellulase-producing organisms with high specific activity and theoretical studies on the  mechanism of action of a system on a complex polymer are the things that should be paid special attention to (Saritha et al., 2012).
Alkaline pretreatments increase the digestibility of cellulose by increasing the solubility of lignin.Sodium, calcium and ammonium hydroxides are suitable for this process.NaOH causes swelling, increasing the internal surface of cellulose and reducing the degree of polymerization and crystallization, which causes lignin disruption.Lime pretreatment removes amorphous material.Lignin removal increases enzyme efficiency by reducing non-productive adsorption sites for enzymes and increasing cellulose accessibility.This method is more effective on agricultural residues than wood materials.(Kumar and Wyman, 2009;Playne, 1984;Saritha et al., 2012).It seems that the use of biological methods (bacterial pretreatment), green synthesis, and Alkaline pretreatments to extract cellulose from agricultural wastes can be used in combination with each other or alone due to their biocompatibility and less damage to the environment and have maximum efficiency and potential in cellulose extraction.

Cellulose extraction from agricultural wastes with different methods and applications in industry and agriculture
Nanocrystalline cellulose (NCC) has received much attention due to its biocompatibility, stability, high aspect ratio, and abundance of -OH groups (Platnieks et al., 2021).In a study, lignin and hemicellulose of banana peel powder were removed by alkaline pretreatment (NaOH), bleaching treatment (sodium hypochlorite solution), and acid hydrolysis (sulfuric acid) methods to synthesize nanocrystalline cellulose (NCC) Infrared spectroscopy, X-ray diffraction, electron microscopy, and thermogravimetric analysis were used to investigate the properties of nanocrystalline cellulose (Mishra et al., 2022).The yield of extracted NCC was 29.9%.The infrared spectroscopy results determined the increase in the degree of crystallinity.The observations showed that the structure of NCC remained intact after hydrolysis, and the yield of extracted NCC was 9.29%.Also, the results showed high NCC stability, particle size of 209 nm, and zeta potential of − 43 mV.It seems that nanocellulose extracted from banana peel powder can be used as a tablet supplement for oral delivery, as a main component of nanocomposite film due to its good tensile strength, and as a conductive film in biosensors (Mishra et al., 2022).
Date syrup (as one of the agricultural wastes) was used to produce bacterial cellulose using Gluconastobacter xylinus.Fourier transform infrared spectroscopy (FTIR), vegetative electron microscopy, and X-ray diffraction were used to determine the structure of bacterial cellulose, cellulose fibers, and crystallinity of the samples (Moosavi and Yousefi, 2011).After 14 days of incubation at 28 • C, the highest yield of cellulose was obtained.This bacterium's efficient production of cellulose lies in its ability to synthesize glucose from various carbon substrates, followed by the polymerization of glucose into cellulose.Studies have shown that G. xylinus has two main amphibolic pathways, including 1) the pentose phosphate cycle for the oxidation of carbohydrates and 2) The Krebs cycle for the oxidation of organic acids and related compounds.
The presence of reducing sugars in date sap (especially glucose) is the primary substrate for cellulose production (Moosavi and Yousefi, 2011;Tajima et al., 2021).Potato peel waste (PPW) is used for bacterial cellulose (BC) production by Gluconacetobacter xylinus.In another research, PPW was purified by 2 mm of different mineral acids (Abdelraof et al., 2019).The results revealed that potato peel and nitric acid could be useful and economical as a substrate for bacterial cellulose synthesis (Abdelraof et al., 2019).
Rice straw as lignocellulosic biomass includes cellulose, hemicellulose, and lignin biopolymers.The cellulose present in rice straw is used in engineering applications, such as the production of bio-composites.
Studies have shown that one ton of rice paddy produces 290 kg of rice straw.Burning rice straw in the field causes many environmental problems for humans and the environment, so it is necessary to provide a method for the optimal use of rice straw (Nanayakkara et al., 2017).For this purpose, research was conducted to develop an environmentally friendly and efficient method for synthesizing cellulose from rice straw.Chemical pretreatments such as dewaxing, exfoliation, and removal of hemicellulose and silica were used.Spectroscopy was used to confirm the formation of pure cellulose during the extraction process.The morphology of the extracted cellulose was analyzed using a scanning electron microscope (SEM) (Nanayakkara et al., 2017).The lignocellulosic stalk of sweet sorghum, known as bagasse (SSB), is the raw material for biological conversion as biofuel as well as other chemicals (Umagiliyage et al., 2015).A study used alkaline pre-treatment to reduce lignin content and cellulose synthesis.FTIR and SEM images were used for compositional and microstructural changes caused by alkaline pre-treatment (Umagiliyage et al., 2015).The pre-treatment used was effective in removing lignin and had a high efficiency of cellulose (Umagiliyage et al., 2015).
Superabsorbent hydrogels are another cellulose product.Cellulose synthesized from agricultural waste through chemical or mechanical methods can be used for this purpose.These hydrogels act as soil conditioners, water retainers, fertilizers, and nutrients in agricultural fields (Li and Chen, 2020).
Chemical approaches focus on polymerization through the formation of covalent bonds.Meanwhile, physical approaches depend on the molecular assembly connected by hydrogen and/or ionic bonds between biopolymers (Li and Chen, 2020).In a study, novel semi-interpenetrating polymer networks (semi-IPNs), the superabsorbent resin with slow-release nitrogen (Urea) and phosphorus (potassium hydrogen phosphate) fertilizer (WSC-g-PAA/PVA/NP), based on wheat straw cellulose-g-poly poly (acrylic acid) (WSC-g-PAA) network and linear polyvinyl alcohol (PVA) was prepared by solution polymerization (Li et al., 2015).
Wheat straw (WS), a by-product of crop production, has advantages, such as being cheap and abundantly available.It contains 40-60% natural cellulose.Wheat straw cellulose (WSC) can be easily exploited for the preparation of SAR (Superabsorbent resin) due to its unique features, such as having a large number of hydrophilic groups (Li et al., 2015).Controlled release fertilizer based on SAR of semi-IPNs was prepared by solution polymerization, during which graft copolymerization and semi-penetration occurred between WS, AA, and PVA.The water absorption and slow-release test results showed that the product has excellent swelling capacity and slow-release properties.Adding WSC-g-PAA/PVA/NP to soil can significantly reduce nutrient leaching losses and improve soil water holding capacity (Li et al., 2015).According to these results, adding gel to the soil can improve the soil's water-holding capacity and reduce the amount of water evaporation.The water absorbed in the gels can be gradually removed by decreasing the soil moisture and then absorbed by the plants.
Meanwhile, the nutrients trapped in the gels can also be released along with the water.As a result, the swollen gels are just like small reservoirs for crops, and this property of the gel has a clear advantage over other traditional fertilizers (Bakass et al., 2002;Johnson, 1984;Li et al., 2015).It seems that using cellulose as a super absorbent has increased the efficiency of the gel in keeping nutrients and moisture.
In a study, a novel eco-friendly aerogel was prepared from waste cellulose derived from hemp stalks for the sustainable release of fertilizers.This approach involves replenishing bio-waste in the soil with the addition of fortifying nutrients.Cellulose was converted to carboxymethyl cellulose (HCMC).The features of the synthesized aerogel were the highly porous structure, large free volume among the polymer chains, the presence of a large number of hydrophilic groups, high flexibility, and superabsorbent behavior.It is a practical approach to agricultural waste management and has a high potential for sustainable farm applications (Kaur et al., 2023).Rice straw, as a lignocellulosic biomass, was used to prepare environmentally friendly hydrophilic polymer to improve bean yield in sandy soil.The results showed that the grain yield and nutrient content of bean seeds increased due to the use of compatible hydrophilic polymer.Also, the efficiency of water consumption increased.Rice straw can become a main source for synthesizing environmentally compatible hydrophilic hydrogels (Abou-Baker et al., 2020).
Studies have shown that agricultural waste is a renewable carbonbased organic energy source.Plant biomasses are rich in cellulosecontaining lignocelluloses and hemicelluloses that produce fermentable sugars due to hydrolysis.The released cellulose and hemicellulose can be hydrolyzed biologically using enzymes and physicochemicals using high-pressure steam or dry heat with acids, alkalis, solvents, etc., to release reducing sugars, which can be fermented to bioethanol by solubilizing clostridia.Biobutanol is a green fuel with many uses compared to other fuels such as ethanol, methanol and gasoline (Maheshwari and Shrivastava, 2023).To overcome the current energy crisis and environmental deterioration, producing fuel from sustainable and renewable sources is the major goal for an energy-demanding society.Agricultural wastes constitute a significant fraction (1.5 ×10 11 tons/annum) of lignocellulose biomass, and this resource can be utilized as feedstock for the generation of biofuels (Pattanaik et al., 2019).The alkaline pretreatment method evaluated bioethanol production from lignocellulosic biomass of rice and wheat straw.This pretreatment improved the efficiency of the bioconversion of cellulose to glucose and led to an increase in the ethanol yield of rice straw (Adeyemi et al., 2019).
Food packaging plays an important role in food safety.Packaging is known as a protective layer on the outside of the food that protects the food from any physical, chemical, or biological hazards.Various polymers that significantly contribute to forming packaging films have been studied and are available in the market (Saberi Riseh et al., 2023c;Saberi Riseh et al., 2023g).Accordingly, the appropriate selection of food packaging materials can prevent food spoilage.Cellulose is an inexpensive material with suitable mechanical properties in the food industry.Cellulose and nanocellulose have been considered in the food packaging industry due to their unique characteristics, biodegradability, and outstanding physical and mechanical properties.Cellulose has a high thermal resistance and can act as a protector against ultraviolet rays.It has the ability to carry antioxidant and antibacterial agents.Cellulose-based fibers are biodegradable and renewable and can be used to prepare various polymer composites because they are non-corrosive, combustible, and non-toxic (Liu et al., 2021).In a study, agricultural wastes such as cocoa pod husk and sugarcane bagasse were used to synthesize food packaging biofilms.The results showed that the best bio-plastic film with balanced tested physicochemical properties went to 75꞉25 (ratio of cellulose to fiber) bio-plastic, as water absorption and the Water vapor permeability properties played crucial roles in selecting the suitable bio-plastic for food packaging.It could reduce the possibility of mould growth on the bio-plastic surface and prevent the transfer of moisture between food and environment, preserving the bio-plastic and food for longer.In addition, the hydrophilic nature of cellulose-based bio-plastic reduced the water vapor barrier that could cause the resulting packaging material's brittleness and poor mechanical properties.Adding or incorporating fibers in a small amount in the bio-plastic composite reduced the susceptibility towards the water as water molecules could not diffuse into the composite.In the future, more studies on the cocoa pod husk incorporated with sugarcane bagasse waste could contribute to the economic growth of society and promote a green environment as the agricultural wastes can be converted into new value-added products (Azmin and Nor, 2020).
Table 1 documents other research regarding the application of agricultural wastes in different industries.

Advantages of cellulose as a bio-renewable polymer
Recently, the use of biopolymers in agriculture has been expanded as safe and renewable resources to achieve the goals of sustainable agriculture (Saberi Riseh et al., 2023b;Saberi Riseh et al., 2023d;Saberi Riseh et al., 2023h;i).In this regard, cellulose and its derivatives are one of the promising biopolymers (Saberi Riseh et al., 2023a).Researchers and scientists have used natural cellulose fibers from various bio-renewable sources worldwide due to their properties, such as biodegradability, easy availability and compatibility with the environment, flexibility, easy processing, and impressive physical and mechanical properties (Pappu et al., 2019;Uppal et al., 2022).Materials based on natural cellulose fibers find their applications in several fields, from automotive to biomedicine (Beluns et al., 2021;Rana et al., 2022).Natural cellulose fibers have been frequently used as a reinforcing component in polymers to add specific properties to the final product(A.S. Singha and Thakur, 2009b).Natural fiber-reinforced polymer composite materials can be classified as a class that seeks to address many environmental and economic issues associated with synthetic fiber-reinforced composites (Singha and Thakur, 2010).Bio-renewable materials, especially natural cellulosic polymers, are one of the largest and most renewable sources of environmentally friendly raw materials.In fact, cellulose, an important component of all-natural fibers, is earth's most abundant natural polymer (Zielińska et al., 2021).Flexibility, easy processing, recyclability, and compatibility with excellent lightweight mechanical properties are the advantages of this natural polymer (Thakur et al., 2011).
With the development of science, the production of cellulose-based materials (such as cellulose fibers, cellulose films, cellulose hydrogels, cellulose aerogels, and composites) that are environmentally friendly and have practical use has been developed.Cellulosic aerogels possess the renewable, biocompatible, and biodegradable properties of cellulose and also have additional advantages such as low density, high porosity, and large specific surface area, making them one of the most promising materials in the 21st century (Long et al., 2018;Wang et al., 2016).Other advantages of cellulose include (Joseph et al., 2020;Long et al., 2018;Romruen et al., 2022;Sarkar et al., 2012;Wei et al., 2019): 1-Agricultural waste, as the main source of cellulose, is abundantly available and cheap.
2-The cellulose chain is rich in hydroxyl groups.These hydroxyl groups form a stable three-dimensional network structure.The physical interconnection of intramolecular and intermolecular hydrogen bonds forms this stable network.
3-Chemical modification of cellulose to improve the mechanical strength and structural characteristics of cellulose-based compounds is relatively easy.
4-A reinforcing material with low density and high mechanical properties.

Conclusions and future perspective
The increase of the world population and the increasing need for food, the management of agricultural products (the production of healthy products, resistant to pests and diseases and with high performance) and agricultural waste on the one hand, and the need for super absorbent polymers with the ability to release controlled has led scientists to increase the use of natural and biodegradable polymers and market them.Agricultural wastes can be widely used as accessible natural resources with a high percentage of cellulose.However, the extraction and optimal productivity of these wastes to produce cellulose require high-performance and high-efficiency methods.Cellulose extracted from agricultural waste can be used in various fields of industry, agriculture, food packaging, and medicine.Since cellulose is a natural biocompatible and degradable polymer, it is a crucial application option.Cellulose has surface chemical properties that are easily modified to contribute to the release of fertilizers.In addition, cellulose's high hydrophilicity helps retain soil moisture for plant growth.Cellulose has surface chemical properties that are easily modified to contribute to the release of fertilizers.In addition, cellulose's high hydrophilicity helps retain soil moisture for plant growth.
From a future perspective, paying attention to correctly managing agricultural waste is necessary to use agricultural waste intelligently.Proper recycling of waste from fruits on the farm as well as in urban areas is the first way to achieve this goal.Cellulose extraction from agricultural waste can be considered as a carrier or coating of agricultural fertilizers and encapsulation of bacteria.Because of the use of cellulose, the costs related to using natural polymers are reduced.On the other hand, a natural and renewable polymer derived from the plant is used to increase the yield and quality of the plant.Using cellulose as biofuel is another future perspective that should be considered.Cellulose extracted from agricultural waste can be considered a raw material for producing biofuels (bioethanol, biobutanol, biogas, and biohydrogen).Specialists in the fields of agriculture and chemistry Around the World should apply the use of agricultural waste to achieve the above goals on a large scale.

Declaration of Competing Interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Fig. 3 .
Fig. 3.The pathway of synthesis of different types of cellulose from type I cellulose.

Table 1
The use of agricultural wastes for the extraction of cellulose for various applications.