ReviewLactic acid production from lignocellulose-derived sugars using lactic acid bacteria: Overview and limits
Introduction
Lactic acid (2-hydroxypropanoic acid, CH3–CH(OH)–COOH) is a natural organic acid with a long history of use in the food and non-food industries, including the cosmetic and pharmaceutical industries, and for the production of oxygenated chemicals, plant growth regulators, and special chemical intermediates (Oshiro et al., 2009, Singhvi et al., 2010, Tashiro et al., 2011). Currently, there is an increased demand for lactic acid as a feedstock for the production of biopolymer poly-lactic acid (PLA), which is a promising biodegradable, biocompatible, and environmentally friendly alternative to plastics derived from petrochemicals. PLA has many uses in surgical sutures, orthopedic implants, drug delivery systems, and disposable consumer products (Adnan and Tan, 2007), and its use would significantly alleviate waste disposal problems. The physical properties of PLA depend on the isomeric composition of lactic acid. Pure isomers, l- and d-lactic acid, are more valuable than the racemic dl form because each isomer has its own specific industrial application. l-Lactic acid is used for the synthesis of poly l-lactic acid (PLLA), a semi-crystalline biodegradable and thermostable polymer that has a potentially large market in goods packaging. PLLA has high tensile strength and low elongation with a high modulus that makes it suitable for medical products used in orthopedic fixation (e.g., pins, rods, ligaments, etc.), cardiovascular applications (e.g., stents, grafts, etc.), dental applications, intestinal applications, and sutures (John et al., 2006a). d-Lactic acid is used for the production of poly d-lactic acid (PDLA) (John et al., 2009). These pure polymers are relatively heat sensitive, while stereocomplexes of PLLA and PDLA have a melting point ∼50 °C higher than their respective pure polymers (Ikeda et al., 1987, Tsuji and Fukui, 2003) and are more biodegradable (de Jong et al., 2001, Tashiro et al., 2011). The ratio of l- and d-lactic acids influences the properties and the degradability of PLA (Kharras et al., 1993).
Lactic acid can be produced either by chemical synthesis or by microbial fermentation. Chemical synthesis from petrochemical resources always results in racemic mixture of dl-lactic acid, which is a major disadvantage of this approach (Hofvendahl and Hahn-Hägerdal, 2000). Conversely, microbial lactic acid fermentation offers an advantage in terms of the utilization of renewable carbohydrate biomass, low production temperature, low energy consumption, and the production of optically high pure lactic acid by selecting an appropriate strain (Ilmen et al., 2007, Pandey et al., 2001). Presently, almost all lactic acid produced globally is manufactured by fermentation routes. In particular, there have been numerous studies of lactic acid production by lactic acid bacteria (LAB) in comparison with other microorganisms.
The demand for lactic acid has increased considerably due to its wide range of applications; however, the high cost of the raw materials, e.g., starch and refined sugars, which accounts for the highest portion of the production cost, represents one of the most serious obstacles for the fermentative production of lactic acid to compete with chemical synthesis (Datta et al., 1995). Cheap raw materials are essential for the feasibility of the biotechnological production of lactic acid because polymer producers and other industrial users usually require large quantities of lactic acid at a relatively low cost. The use of low-cost non-food materials for lactic acid production appears to be more attractive because they do not have any impact on the human food chain. Nowadays, lignocellulosic materials from agricultural, agro-industrial, and forestry sources represent a potentially inexpensive and renewable carbohydrate feedstock for the large-scale fermentation of lactic acid due to their abundance, low price, high polysaccharide content, and renewability (Duff and Murray, 1996, Parajo et al., 1996, Taniguchi et al., 2005, Wyman, 1999). However, the cellulose and hemicellulose in lignocellulose are not directly available for bioconversion to lactic acid because of their intimate association with lignin (Schmidt and Thomsen, 1998) and the lack of hydrolytic enzymes in LAB (Tokuhiro et al., 2008).
There have been numerous investigations on the development of biotechnological processes for lactic acid production, with the ultimate objective of making the process more effective and economical. In this review, we focus on the “conventional” processes for lactic acid fermentation by LAB from lignocellulosic biomass and lignocellulose-derived sugars. Moreover, we describe the limitations of lactic acid production using such materials. We also describe fermentative processes and technologies with practical examples, the metabolism of biomass-derived sugars, and the promising prospects of lactic acid fermentation.
Section snippets
Composition of lignocellulosic biomass
The global production of plant biomass, of which over 90% is lignocellulose, amounts to ∼200 × 109 tons per year, where ∼8–20 × 109 tons of the primary biomass remains potentially accessible (Lin and Tanaka, 2006). Lignocellulosic biomass is organic material derived from a biological origin, and represents the most abundant global source of biomass that has been largely unutilized (Lin and Tanaka, 2006). It is mainly composed of cellulose (insoluble fibers of β-1,4-glucan), hemicellulose
Improvement of lactic acid production by LAB in the field of microbial technology
It has generally been observed that pH, nutrient concentration, substrate concentration, end products concentration, and temperature significantly affect the growth of LAB and lactic acid production. These factors may decrease cell density and the lactic acid titer, yield, and productivity in some cases. Researchers in the field of microbial technology have conducted numerous studies to establish an efficient method of lactic acid production by LAB.
In lactic acid fermentation, low pH has an
Metabolism of lignocellulose-derived sugars by LAB
LAB can be classified into 2 groups on the basis of the end product of their fermentation: homofermentative and heterofermentative. Homofermentative LAB virtually produce only lactic acid, whereas other products are generated by heterofermentative LAB along with lactic acid (Axelsson, 1993, Hofvendahl and Hahn-Hägerdal, 2000).
Fig. 2 shows the metabolic pathways of hexose and pentose in LAB. When hexose sugars such as glucose are used, they are consumed by the Streptococcus, Lactococcus,
Designed biomass study and conclusions
Currently, the fermentative production of useful substances, e.g., biomaterials and biofuels, from various renewable resources by microorganisms has become more attractive. For this purpose, it is essential that the used strain should consume the renewable resources as substrates to produce the useful substances. In a number of recent studies, a targeted substrate is initially decided upon, e.g., several types of biomass and by-products from industrial factories. Two main approaches are then
References (293)
- et al.
Isolation and characterization of novel lactic acid bacterium for efficient production of l (+)-lactic acid from xylose
J. Biotechnol.
(2010) - et al.
Effective l (+)-lactic acid production by co-fermentation of mixed sugars
J. Biotechnol.
(2010) - et al.
Modification of metabolic pathways of Saccharomyces cerevisiae by the expression of lactate dehydrogenase and deletion of pyruvate decarboxylase genes for the lactic acid fermentation at low pH value
J. Ferment. Bioeng.
(1998) - et al.
A novel concept of bioreactor: specialized function two-stage continuous reactor, and its application to lactose conversion into lactic acid
J. Biotechnol.
(1996) - et al.
Ammonium lactate production by Lactobacillus lactis BME5-18M in pH-controlled fed-batch fermentations
Biochem. Eng. J.
(2004) Production of bioethanol from lignocellulosic materials via the biochemical pathway: a review
Energy Convers. Manage.
(2011)- et al.
Progress in bioethanol processing
Prog. Energ. Combust.
(2008) - et al.
Evaluation of novel fungal cellulase preparations for ability to hydrolyze softwood substrates—evidence for the role of accessory enzymes
Enzyme Microb. Technol.
(2005) - et al.
Effect of poly (ethylene glycol) on enzymatic hydrolysis and adsorption of cellulase enzymes to pretreated lignocellulose
Enzyme Microb. Technol.
(2007) - et al.
Revalorization of hemicellulosic trimming vine shoots hydrolyzates trough continuous production of lactic acid and biosurfactants by L. pentosus
J. Food Eng.
(2007)
Comparison of four different chemical pretreatments of corn stover for enhancing enzymatic digestibility
Biomass Bioenergy
Recovery of lactic acid from sodium lactate by ion substitution using ion-exchange membrane
Sep. Purif. Technol.
Lactic acid production from corn stover using mixed cultures of Lactobacillus rhamnosus and Lactobacillus brevis
Bioresour. Technol.
Technological and economical potential of polylactic acid and lactic acid derivatives
FEMS Microbiol. Rev.
Physically crosslinked dextran hydrogels by stereocomplex formation of lactic acid oligomers: degradation and protein release behavior
J. Control. Release
l-Lactic acid production by Lactobacillus casei fermentation using different fed-batch feeding strategies
Process Biochem.
Bioconversion of forest products industry waste cellulosics to fuel ethanol: a review
Bioresour. Technol.
Modeling and optimization of the dilute-sulfuric-acid pretreatment of corn stover, poplar and switchgrass
Bioresour. Technol.
Synergy between an endoglucanase and cellobiohydrolases from Trichoderma koningii
Chem. Eng. J. Biochem. Eng. J.
Lactic acid production from wheat straw hemicellulose hydrolysate by Lactobacillus pentosus and Lactobacillus brevis
Bioresour. Technol.
l-Lactic acid production from apple pomace by sequential hydrolysis and fermentation
Bioresour. Technol.
Electrodialysis as a useful technique for lactic acid separation from a model solution and a fermentation broth
Desalination
Pretreatments to enhance the digestibility of lignocellulosic biomass
Bioresour. Technol.
Cellulase for commodity products from cellulosic biomass
Curr. Opin. Biotechnol.
Factors affecting the fermentative lactic acid production from renewable resources
Enzyme Microb. Technol.
Effective lactic acid production by two-stage extractive fermentation
J. Ferment. Bioeng.
Simultaneous saccharification and fermentation of potato starch wastewater to lactic acid by Rhizopus oryzae and Rhizopus arrhizus
Biochem. Eng. J.
Semicontinuous production of lactic acid in a bioreactor coupled with nano-filtration membranes
Enzyme Microb. Technol.
Ethanol and thermotolerance in the bioconversion of xylose by yeasts
Adv. Appl. Microbiol.
Direct lactic acid fermentation: focus on simultaneous saccharification and lactic acid production
Biotechnol. Adv.
Metabolic engineering of Saccharomyces cerevisiae for production of carboxylic acids: current status and challenges
FEMS Yeast Res.
Efficient homofermentative l-(+)-lactic acid production from xylose by a novel lactic acid bacterium, Enterococcus mundtii QU 25
Appl. Environ. Microbiol.
Isolation and characterization of lactic acid bacterium for effective fermentation of cellobiose into optically pure homo l-(+)-lactic acid
Appl. Microbiol. Biotechnol.
Simultaneous saccharification and fermentation of cellulose to lactic acid
Biotechnol. Bioeng.
Experimental design to enhance the production of l-(+)-lactic acid from steam-exploded wood hydrolyzate using Rhizopus oryzae in a mixed-acid fermentation
Process Biochem.
Isolation of lactic acid bacteria from Malaysian foods and assessment of the isolates for industrial potential
Bioresour. Technol.
Lactic acid production from waste sugar cane bagasse derived cellulose
Green Chem.
Lactic acid production from cellobiose and cellotriose by Lactobacillus delbrueckii mutant Uc-3
Appl. Environ. Microbiol.
Enzyme pretreatment of grass lignocellulose for potential high-value co-products and an improved fermentable substrate
Appl. Biochem. Biotechnol.
Water: a traditional solvent pregnant with new applications
Lactic acid bacteria: classification and physiology
Hydrolysis of cellulose using ternary mixtures of purified cellulases
Appl. Biochem. Biotechnol.
Gasification of biomass to produce gaseous products
Energy Source
Identification of thermobacteria and homofermentative, thermophilic, pentose-utilizing Lactobacilli from high temperature fermenting grape musts
J. Appl. Bacteriol.
The “petite-negative” yeast Kluyveromyces lactis has a single gene expression pyruvate decarboxylase activity
Mol. Microbiol.
Fermentations with new recombinant organisms
Biotechnol. Prog.
Continuous lactic acid fermentation with concentrated product recovery by ultrafiltration and electrodialysis
Biotechnol. Lett.
Production of fermentable media from vine-trimming wastes and bioconversion into lactic acid by Lactobacillus pentosus
J. Sci. Food. Agric.
Influence of the metabolism pathway on lactic acid production from hemicellulosic trimming vine shoots hydrolyzates using Lactobacillus pentosus
Biotechnol. Prog.
Production of lactic acid from lactose by free and immobilized Lactobacillus bulgaricus
Biotech-Forum.
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