Efficient succinic acid production using a biochar-treated textile waste hydrolysate in an in situ fibrous bed bioreactor

https://doi.org/10.1016/j.bej.2019.107249Get rights and content

Highlights

  • Utilization of biochar for removal of dyestuff from textile waste hydrolysate.

  • Novel textile waste-based biorefinery strategy for succinic acid production.

  • Optimization of fermentation medium for SA production by Yarrowia lipolytica.

  • Enhanced succinic acid production using an in-situ fibrous bed bioreactor.

Abstract

Textile waste contains biodegradable fraction which can be used as an alternative feedstock for succinic acid production. The feasibility of bioconversion of biochar-treated textile waste hydrolysate into succinic acid was evaluated. A substrate loading of 9% was applied to hydrolyze mixed textile waste and the resultant glucose-rich hydrolysate with dyestuff was collected after enzymatic hydrolysis. Biochar from different pyrolysis temperatures (400–700 °C) and different dosages of the selected biochar (1–5%) were applied to remove colorants. The results showed that biochar had a good performance at a dosage of 2 w/w % on removal of colorant inhibitors. There was no negative effect observed during the subsequent fermentation. After optimization of fermentation media in shake flasks, the resultant succinic acid titer reached 19.6 g/L with a SA yield of 0.76 g/g, supplemented with 30 g/L tryptone. The in situ fibrous bed bioreactor (isFBB) can further improve SA titer, up to 28.8 g/L corresponding to a yield of 0.61 g/g without pH control. Furthermore, a shorter lag phase during succinic acid fermentation in isFBB was observed. It can be concluded that a novel textile waste-based biorefinery approach for succinic acid production aided by biochar sorption was successfully developed.

Introduction

Textile waste generation has increased rapidly due to the fast growth of the fashion industry in recent years [1]. In 2015, the textile waste generation was around 92 million tonnes at global level and is estimated to keep increasing to 148 million tons in 2030 [2]. Currently, around 85% of textile waste is disposed directly in landfills [3], whereas 95% is collected for recycling [4]. Therefore, the direct linear disposal system should be substituted in order to avoid the loss of valuable materials and negative impacts on the environment by the waste [5,6]. This waste stream is a highly feasible starting material for biofuels and platform chemical production [1,3,6,7], since 35–40% of general textile waste consists of cellulose fiber [1]. The bioconversion of textile waste to fermentable sugar has been successfully demonstrated in our recent study [7]. Further investigation should be carried out to evaluate the feasibility of high value-added products from textile waste glucose-rich hydrolysates.

Succinic acid (SA) is classified as one of the top twelve promising chemical building blocks [8,9]. As a versatile platform chemical, SA can be utilized as a precursor in the production of a wide range of commodities, consisting of food additives, clothing fibers, surfactants, and pharmaceuticals [10,11]. The market price of SA ranges from USD 2.40 to 2.60 per kilogram [12], which is more competitive than glucose (USD 0.39/kg) [13,14]. Currently, industrial SA production mainly relies on the traditional fossil-based process. However, chemical processing is sensitive to the crude oil price, as well as environmental issues [11,15]. Therefore, the utilization of the textile waste as feedstock in SA production would provide an appealing opportunity for delivering substantially better economic societal and environmental outcomes.

In this study, a two-step bioconversion process was applied as no microorganism can convert feedstock directly into value-added products [16]. Therefore, enzymatic hydrolysis was firstly carried out in order to convert cotton-based textile waste into a glucose-rich hydrolysate, which was subsequently fermented into SA. However, this hydrolysate contains dyestuff released from textile waste, which may inhibit yeast growth and cause a long lag phase in SA fermentation [17]. The inhibitory effect of azo dyes was also observed during anaerobic methanogenic wastewater treatment [18]. Therefore, efficient removal of dyestuff should be the first priority before fermentation to produce SA. Sorption is one of the most used approaches to remove dyes and other contaminants from water and wastewater due to its high efficiency, easy and low-cost operation [[19], [20], [21], [22]], while activated carbon [23], biochar [21], natural zeolites [24], nanomaterials [25] and polymers [19] are the most frequently used sorbents. Biochar is a carbon-rich solid residue produced via thermochemical conversion process, for example pyrolysis and gasification [26,27]. It has been employed as a sorbent in wastewater treatment to remove a wide range of organic pollutants, including dyestuffs [21,28,29]. It was also reported that biochar can release various cations depending on the feedstock, for example Na, K, Ca, Mg, Fe, and Mg [26,30,31]. The released cations and minerals can relieve the acid stress and serve as nutrients during fermentation [26].

Yarrowia lipolytica is a robust SA producer and it has a great potential in future commercialized SA production, since it exhibits high tolerance to acidic environments and accumulation of products, as well as other environmental stress [32,33]. Y. lipolytica has been widely investigated in our group for waste stream valorization, including food waste, fruit and vegetable waste and crude glycerol [9,11,32]. In addition, the utilization of in situ fibrous bed bioreactor (isFBB) can contribute to a significant improvement in SA productivity when crude glycerol was utilized as the substrate [11]. However, a large amount of alkali was added during fermentation and acidification was further needed when recovering SA crystals from the fermentation broth, which are expensive steps in bio-based SA production [34]. In order to produce SA effectively under low pH conditions, an engineered Y. lipolytica PGC202 was constructed [35] and high yields in SA production can be successfully obtained from pure glucose without pH control using Y. lipolytica PGC202 [36].

To our knowledge, this is the first report that biochar-treated textile waste hydrolysate was used for SA production by engineered Y. lipolytica. In this study, the investigation of biochar characterization and application of biochar to remove colorant impurities from a textile waste hydrolysate were firstly conducted. Then, optimization of the fermentation media (i.e. nitrogen source and initial glucose concentration) was conducted in shake flask scale. Finally, the feasibility of SA fermentations using free cell batch fermentation and isFBB in bench-top scale bioreactor was investigated. The successful demonstration of this study would facilitate the textile materials upcycling and foster the innovation in the direction needed by the industry to support a new textiles economy.

Section snippets

Handling of textile waste

A textile waste mixture was provided by H&M manufacturing plants in China, and was crushed into pieces (around 1 × 1 cm2) using the grinder WSMD 200 × 160 (OMS Machinery Co. Ltd., Zhongshan, China). Freezing sodium hydroxide/urea was employed as a pretreatment method as described in our previous studies [3,7]. Cellulose content in pretreated mixed textile waste was analyzed using the standardized NREL Laboratory Analytical Procedure [37].

Cellulase (Celluclast 1.5 L, Novozymes®, China) with 75

Textile waste hydrolysis in the 2-L bench-top bioreactor

The average cellulose content in pretreated mixed textile waste was 84.8%. Fig. 1 shows the influence of substrate loadings of mixed textile waste on enzymatic hydrolysis. The usage of substrate loading of 9% resulted in the highest glucose concentration of 31.1 g/L, whereas only 14.8 g/L of glucose was recovered at a substrate loading of 3%. The results indicate that the increase of solid concentration did not affect the equilibrium time and the utilization of high solid concentration can lead

Conclusions

This is the first reported study of biochar-treated textile waste hydrolysate in bio-based SA production. A glucose-rich textile waste hydrolysate was collected after 72 h of enzymatic hydrolysis with 9% solid loading. Biochar from paper mill sludge pyrolyzed at 700 °C with a dosage of 2% (w/w) effectively removed dyestuff which inhibited the fermentative production of SA, while no significant loss of glucose was observed. Y. lipolytica PGC202 can successfully produce SA, using treated

Acknowledgments

The authors would like to gratefully acknowledge the Applied Research Grant from City University of Hong Kong (Project No. CityU 9667167). This study was also jointly supported by the National Key Technology Support Program of China (No. 2015BAD15B06), and the International Cooperation Project of Shanghai Municipal Science and Technology Commission (No. 18230710700). Sincere appreciation is dedicated to Dr Liu Hao from South China University of Technology for providing textile waste

References (50)

  • R. Dai et al.

    Inhibitory effect and mechanism of azo dyes on anaerobic methanogenic wastewater treatment: can redox mediator remediate the inhibition

    Water Res.

    (2016)
  • D. Robati et al.

    Removal of hazardous dyes-BR 12 and methyl orange using graphene oxide as an adsorbent from aqueous phase

    Chem. Eng. J.

    (2016)
  • D.D. Sewu et al.

    Highly efficient adsorption of cationic dye by biochar produced with Korean cabbage waste

    Bioresour. Technol.

    (2017)
  • T. Maneerung et al.

    Activated carbon derived from carbon residue from biomass gasification and its application for dye adsorption: kinetics, isotherms and thermodynamic studies

    Bioresour. Technol.

    (2016)
  • S. Wang et al.

    Natural zeolites as effective adsorbents in water and wastewater treatment

    Chem. Eng. J.

    (2010)
  • X. Sun et al.

    Enhanced ethanol production by Clostridium ragsdalei from syngas by incorporating biochar in the fermentation medium

    Bioresour. Technol.

    (2018)
  • X. Yang et al.

    Effect of gasification biochar application on soil quality: Trace metal behavior, microbial community, and soil dissolved organic matter

    J. Hazard. Mater.

    (2019)
  • D. Mohan et al.

    Organic and inorganic contaminants removal from water with biochar, a renewable, low cost and sustainable adsorbent-a critical review

    Bioresour. Technol.

    (2014)
  • M.E. Mahmoud et al.

    Kinetics, isotherm, and thermodynamic studies of the adsorption of reactive red 195 A dye from water by modified Switchgrass Biochar adsorbent

    J. Ind. Eng. Chem.

    (2016)
  • M. Li et al.

    Alkali and alkaline earth metallic (AAEM) species leaching and Cu(II) sorption by biochar

    Chemosphere

    (2015)
  • C. Li et al.

    High efficiency succinic acid production from glycerol via in situ fibrous bed bioreactor with an engineered Yarrowia lipolytica

    Bioresour. Technol.

    (2017)
  • C. Li et al.

    Efficient metabolic evolution of engineered Yarrowia lipolytica for succinic acid production using a glucose-based medium in an in situ fibrous bioreactor under low-pH condition

    Biotechnol. Biofuels

    (2018)
  • Z. Cui et al.

    Engineering of unconventional yeast Yarrowia lipolytica for efficient succinic acid production from glycerol at low pH

    Metab. Eng.

    (2017)
  • Q. Yu et al.

    Exploring succinic acid production by engineered Yarrowia lipolytica strains using glucose at low pH

    Biochem. Eng. J.

    (2018)
  • A. Goshadrou et al.

    Characterization of ionic liquid pretreated aspen wood using semi-quantitative methods for ethanol production

    Carbohydr. Polym.

    (2013)
  • Cited by (37)

    View all citing articles on Scopus
    View full text