Lignocellulosic Biorefineries and Downstream Processing

A special issue of Fermentation (ISSN 2311-5637). This special issue belongs to the section "Industrial Fermentation".

Deadline for manuscript submissions: 30 April 2024 | Viewed by 21862

Special Issue Editor


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Guest Editor
School of Chemical Engineering and Light Industry, Guangdong Provincial Key Laboratory of Plant Resources Biorefinery, Guangdong University of Technology, Guangzhou 510006, China
Interests: biofuels (ethanol and butanol); biomass pretreatment; downstream processing; lignocellulosic biorefineries; adsorption and separation; platform chemicals
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Special Issue Information

Dear Colleagues,

The development of biofuels or bio-based chemicals utilizing sustainable biomass feedstocks has attracted worldwide interest due to changing gasoline prices, climate change, and other detrimental environmental impacts from burning fossil fuels. However, it is inevitable that certain carboxylic acids, furan aldehydes, and phenolic chemicals was formed during the pretreatment of lignocellulosic biomass. These "toxic substances" will negatively impact the growth and metabolism of microorganisms, inhibit sugar uptake, and increase the cost of fermentation. Therefore, development of microorganisms with higher fermentation inhibitors tolerant and detoxification of fermentation inhibitors are the key to improve the fermentation performance of the biomass hydrolyzate, and improve the yield of fermented products.

In view of the "three-low" problems of low product concentration, low reaction rate and low yield in the biological manufacturing process, and facing the "three-high" challenges of high wastewater discharge, high energy consumption and high downstream separation and purification costs, developing advanced separation and purification technologies of fermented products to improve the quality of bio-based products, reduce production costs, and meet large-scale production needs are also the key to achieving benefits, thereby promoting the development of the lignocellulosic biorefinery industry.

This Special Issue aims to collect papers highlighting some of the excellent research being done in the field of lignocellulosic biorefineries and downstream processing. The topics of interest allow, but are not limited to:

  • sustainable bioenergy;
  • bio-based chemicals production from lignocellulosic derived sugars;
  • lignocellulosic biorefineries;
  • biomass pretreatment (lignin-first or hemicellulose-first deconstruction strategy);
  • biomass hydrolysate detoxification;
  • downstream processing for recovery of fermented products;
  • fermentation-separation coupled integrated process.

Prof. Dr. Xiaoqing Lin
Guest Editor

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Keywords

  • lignocellulosic biomass
  • biomass pretreatment
  • cellulosic butanol
  • cellulosic ethanol
  • bio-based chemicals
  • hydrolysate detoxification
  • downstream processing
  • adsorption and separation
  • membrane separation
  • process integration

Published Papers (7 papers)

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Research

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14 pages, 1568 KiB  
Article
Biological Detoxification of the Inhibitors in Corncob Acid Hydrolysate Using Aspergillus niger
by Jinbao Yin, Chen Wang, Yilian Li, Bo Lv, Haosheng Lv, Yuyuan Xue, Jing Wu and Jianan Zhang
Fermentation 2023, 9(9), 854; https://doi.org/10.3390/fermentation9090854 - 19 Sep 2023
Viewed by 871
Abstract
The biological detoxification of lignocellulose hydrolysate is an effective method through which to enhance microbial fermentation efficiency. In this study, an inhibitor-tolerant strain of A. niger (Aspergillus niger) was used for the biological detoxification of corncob hydrolysate. The results showed that [...] Read more.
The biological detoxification of lignocellulose hydrolysate is an effective method through which to enhance microbial fermentation efficiency. In this study, an inhibitor-tolerant strain of A. niger (Aspergillus niger) was used for the biological detoxification of corncob hydrolysate. The results showed that A. niger M13 can tolerate a concentration of at least 7.50 ± 0.19 g/L of acetic acid, 1.81 ± 0.13 g/L of furfural, and 1.02 ± 0.10 g/L of HMF (5-Hydroxymethylfurfural). The spores had a higher detoxification efficiency than the mycelial pellets with a detoxification rate of 0.1566 g/L/h, 0.1125 g/L/h, and 0.015 g/L/h for acetic acid, furfural, and HMF, respectively. The cell preferentially consumed furfural, then HMF, before simultaneously degrading acetic acid and glucose. A. niger M13 spores could accumulate small amounts of citric acid directly from undetoxified hydrolysate at a concentration of about 6 g/L. Therefore, A. niger M13 can serve as an excellent biological detoxification strain and a potential citric acid fermenting strain when using undetoxified lignocellulosic hydrolysates. Full article
(This article belongs to the Special Issue Lignocellulosic Biorefineries and Downstream Processing)
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14 pages, 3843 KiB  
Article
Biomass Deacetylation at Moderate Solid Loading Improves Sugar Recovery and Succinic Acid Production
by Nurul Adela Bukhari, Abdullah Amru Indera Luthfi, Nuraishah Abd Rahim, Abu Bakar Nasrin, Mohamad Azri Sukiran and Soh Kheang Loh
Fermentation 2023, 9(3), 235; https://doi.org/10.3390/fermentation9030235 - 28 Feb 2023
Cited by 2 | Viewed by 1110
Abstract
Biomass deacetylation with alkali prior to dilute acid pretreatment can be a promising approach to reduce the toxicity of the resulting hydrolysates and improve microbial fermentation. In this study, the effect of mild alkaline treatment of oil palm trunk (OPT) biomass on succinic [...] Read more.
Biomass deacetylation with alkali prior to dilute acid pretreatment can be a promising approach to reduce the toxicity of the resulting hydrolysates and improve microbial fermentation. In this study, the effect of mild alkaline treatment of oil palm trunk (OPT) biomass on succinic acid production was evaluated. Deacetylation was carried out under different conditions: NaOH loadings (1–5%, w/v) and reaction times (15–90 min) at 100 °C. Deacetylation using 1% (w/v) NaOH within 15 min was sufficient to achieve a high acetic acid removal of 5.8 g/L with minimal sugar loss. Deacetylation under this condition resulted in a total sugar concentration of 55.8 g/L (18.0 g/L xylose and 37.8 g/L glucose), which was 37% higher than that of non-deacetylated OPT. Subsequently, succinic acid production using Actinobacillus succinogenes was also improved by 42% and 13% in terms of productivity and yield, respectively, at 10% (w/v) solid loading. This further demonstrated that mild alkaline treatment prior to dilute acid pretreatment is a promising strategy to improve succinic acid production. This study provides a facile approach for reducing the most influential inhibitory effect of acetic acid, and it can be applied to the exploitation of lignocellulosic biomass resources for succinic acid, biofuels, and/or other biochemical co-production in the future. Full article
(This article belongs to the Special Issue Lignocellulosic Biorefineries and Downstream Processing)
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14 pages, 3923 KiB  
Article
Ammonia–Mechanical Pretreatment of Wheat Straw for the Production of Lactic Acid and High-Quality Lignin
by Yulian Cao, Haifeng Liu, Junqiang Shan, Baijun Sun, Yanjun Chen, Lei Ji, Xingxiang Ji, Jian Wang, Chenjie Zhu and Hanjie Ying
Fermentation 2023, 9(2), 177; https://doi.org/10.3390/fermentation9020177 - 15 Feb 2023
Cited by 2 | Viewed by 1594
Abstract
In this study, wheat straw was fractionated into carbohydrates (cellulose and hemicellulose) by ammonia–mechanical pretreatment for l-lactic acid fermentation. Under optimal conditions (aqueous ammonia concentration: 19% w/w, liquid–solid ratio: 2.1:1 w/w, holding time: 4.80 h), the delignification was more than [...] Read more.
In this study, wheat straw was fractionated into carbohydrates (cellulose and hemicellulose) by ammonia–mechanical pretreatment for l-lactic acid fermentation. Under optimal conditions (aqueous ammonia concentration: 19% w/w, liquid–solid ratio: 2.1:1 w/w, holding time: 4.80 h), the delignification was more than 60%. After enzymatic hydrolysis, the maximum conversions of cellulose and hemicellulose were 92.5% and 83.4% based on the pretreatment residue, respectively. The wheat straw hydrolysate was used to produce l-lactic acid with Thermoanaerobacter sp. DH-217G, which obtained a yield of 88.6% and an optical purity of 99.2%. The ammonia–mechanical pretreatment is an economical method for the production of fermentable monosaccharide, providing potential for further downstream high value-added applications. Full article
(This article belongs to the Special Issue Lignocellulosic Biorefineries and Downstream Processing)
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13 pages, 999 KiB  
Article
Synergistic Enhancement Effect of Compound Additive of Organic Alcohols and Biosurfactant on Enzymatic Hydrolysis of Lignocellulose
by Cuiyi Liang, Qifa Feng, Si Lu, Qiong Wang, Yunzi Hu, Zhongming Wang, Wen Wang and Wei Qi
Fermentation 2022, 8(12), 725; https://doi.org/10.3390/fermentation8120725 - 11 Dec 2022
Cited by 3 | Viewed by 1260
Abstract
The insufficient of lignocellulose degradation enzymes, such as cellulase and hemicellulase, is the major obstacle that hinders the bioconversion of lignocellulosic biomass to monosaccharides, especially during the woody biomass hydrolysis process. The addition of additives has received significant attention due to their enhancement [...] Read more.
The insufficient of lignocellulose degradation enzymes, such as cellulase and hemicellulase, is the major obstacle that hinders the bioconversion of lignocellulosic biomass to monosaccharides, especially during the woody biomass hydrolysis process. The addition of additives has received significant attention due to their enhancement of the enzymatic degradation efficiency of lignocellulose. In the present study, a combination of organic alcohols and a biosurfactant could synergistically enhance the saccharification of the cellulose substrate of Avicel, as well as that of pretreated poplar. Results showed that compound additives can greatly improve the conversion rate of enzymatic hydrolysis. The combination of 0.1% (v/v) n-decanol and 1% (v/v) sophorolipid dramatically increased the poplar enzymatic conversion rate from 17.9% to 85%, improving it by 67.1%. Enzyme-rich Hypocrea sp. W63 was fermented to obtain beta-glucosidase (BGL) and xylanase (XYL), which were used as auxiliary enzymes during enzymatic hydrolysis. It was found that the effects of such a combination of additives improved the filter paper activity, stability, and longevity, helping in the recovery of the cellulase cocktail. The compound additives associated with the commercial cellulase and Hypocrea sp. W63 enzyme solution formed an excellent formula for improving the stability of BGL and XYL. The results provide insight into compound additives and the use of a cellulase and auxiliary enzyme cocktail to improve enzymatic hydrolysis for lignocellulose conversion into biofuels. Full article
(This article belongs to the Special Issue Lignocellulosic Biorefineries and Downstream Processing)
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13 pages, 1585 KiB  
Article
Ethanol Production through Optimized Alkaline Pretreated Elaeis guineensis Frond Waste from Krabi Province, Thailand
by Poomhatai Kooprasertying, Wirat Vanichsriratana, Sarote Sirisansaneeyakul, Nicom Laemsak, Afrasiab Khan Tareen, Zahoor Ullah, Pramuk Parakulsuksatid and Imrana Niaz Sultan
Fermentation 2022, 8(11), 648; https://doi.org/10.3390/fermentation8110648 - 17 Nov 2022
Cited by 3 | Viewed by 1720
Abstract
Oil palm frond as an abundant and inexpensive lignocellulosic waste was used to optimize alkaline pretreatment for ethanol production. The studied lignocellulosic waste is one of the largest biomasses (47%) in oil palm waste. Oil palm frond fibers were processed by steam explosion, [...] Read more.
Oil palm frond as an abundant and inexpensive lignocellulosic waste was used to optimize alkaline pretreatment for ethanol production. The studied lignocellulosic waste is one of the largest biomasses (47%) in oil palm waste. Oil palm frond fibers were processed by steam explosion, hot water extraction, and alkaline extraction pretreatment, followed by simultaneous saccharification and fermentation (SSF), for ethanol production as an alternative energy resource. To optimize alkaline extraction for oil palm frond, a Taguchi method with a three-factor design constituted a concentration of NaOH (15%, 20%, and 25%), time (30, 60, and 90 min), and temperature (70, 80, and 90 °C). An optimum alkaline extraction condition of 15% NaOH at 90 °C for 60 min gave the highest percentage of α-cellulose (80.74%) and the lowest percentages of lignin (15.99%), ash (1.05%), and pentosan (2.09%). In addition, the optimized pretreatment condition significantly improved α-cellulose to 52.65% and removed lignin up to 51.78%. Simultaneous saccharification and fermentation (SSF) was carried out with 10% (dry weight) alkaline pretreated OPF fibers, Celluclast 1.5 L (15 FU/gram substrate), Novozyme 188 (15 IU/gram substrate), and Saccharomyces cerevisiae SC90 at 40 and 45 °C. The highest ethanol concentration, theoretical ethanol yield, and ethanol productivity observed at 40 °C were 33.15 g/L, 72.54%, and 0.55 g/L/h, respectively. The results suggest that an optimized alkaline pretreatment process using palm frond as a lignocellulosic waste is a sustainable approach to produce efficient ethanol production. Full article
(This article belongs to the Special Issue Lignocellulosic Biorefineries and Downstream Processing)
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14 pages, 3420 KiB  
Article
Integrated Bioprocess for Cellulosic Ethanol Production from Wheat Straw: New Ternary Deep-Eutectic-Solvent Pretreatment, Enzymatic Saccharification, and Fermentation
by Xiaoling Xian, Lv Fang, Yongxing Zhou, Biying Li, Xiaojie Zheng, Yao Liu and Xiaoqing Lin
Fermentation 2022, 8(8), 371; https://doi.org/10.3390/fermentation8080371 - 05 Aug 2022
Cited by 8 | Viewed by 2089
Abstract
Wheat straw (WS) is an excellent raw material for biofuel ethanol production. However, the recalcitrance of WS prevents its efficient utilization. In this study, a novel ternary deep eutectic solvent (DES) was developed for enhancing component separation and enzymatic saccharification of WS. Without [...] Read more.
Wheat straw (WS) is an excellent raw material for biofuel ethanol production. However, the recalcitrance of WS prevents its efficient utilization. In this study, a novel ternary deep eutectic solvent (DES) was developed for enhancing component separation and enzymatic saccharification of WS. Without any detoxification and sterilization, the DES-treated WS hydrolysate was successfully used to produce ethanol. Overall, this research evaluated the effect of ternary DES pretreatment on WS at various temperatures and adjusted the enzyme load, substrate concentration, and fermentation method of treated WS. The results suggested that the cellulose recovery of treated WS after DES pretreatment (120 °C, 1 h) was 94.73 ± 0.22%, while the removal of xylan and lignin reached 89.53 ± 0.36% and 80.05 ± 0.62%, respectively. Importantly, at enzyme loading of 11.4 filter paper unit (FPU)/g WS with 16% fermentation substrate concentration, 91.15 ± 1.07% of cellulose was hydrolyzed, and the glucose yield was 71.58 ± 1.34%. The maximum ethanol yield of DES-treated WS was 81.40 ± 0.01%. Full article
(This article belongs to the Special Issue Lignocellulosic Biorefineries and Downstream Processing)
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Review

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21 pages, 4128 KiB  
Review
Improve Enzymatic Hydrolysis of Lignocellulosic Biomass by Modifying Lignin Structure via Sulfite Pretreatment and Using Lignin Blockers
by Caoxing Huang, Ruolin Li, Wei Tang, Yayue Zheng and Xianzhi Meng
Fermentation 2022, 8(10), 558; https://doi.org/10.3390/fermentation8100558 - 20 Oct 2022
Cited by 28 | Viewed by 5925
Abstract
Even traditional pretreatments can partially remove or degrade lignin and hemicellulose from lignocellulosic biomass for enhancing its enzymatic digestibility, the remaining lignin in pretreated biomass still restricts its enzymatic hydrolysis by limiting cellulose accessibility and lignin-enzyme nonproductive interaction. Therefore, many pretreatments that can [...] Read more.
Even traditional pretreatments can partially remove or degrade lignin and hemicellulose from lignocellulosic biomass for enhancing its enzymatic digestibility, the remaining lignin in pretreated biomass still restricts its enzymatic hydrolysis by limiting cellulose accessibility and lignin-enzyme nonproductive interaction. Therefore, many pretreatments that can modify lignin structure in a unique way and approaches to block the lignin’s adverse impact have been proposed to directly improve the enzymatic digestibility of pretreated biomass. In this review, recent development in sulfite pretreatment that can transform the native lignin into lignosulfonate and subsequently enhance saccharification of pretreated biomass under certain conditions was summarized. In addition, we also reviewed the approaches of the addition of reactive agents to block the lignin’s reactive sites and limit the cellulase-enzyme adsorption during hydrolysis. It is our hope that this summary can provide a guideline for workers engaged in biorefining for the goal of reaching high enzymatic digestibility of lignocellulose. Full article
(This article belongs to the Special Issue Lignocellulosic Biorefineries and Downstream Processing)
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