Simultaneous Saccharification
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2022 ◽  
Hairui Ji ◽  
Le Wang ◽  
Furong Tao ◽  
Zhipeng Yao ◽  
Xuezhi Li ◽  

Abstract The biomass pretreatment strategies using organic acids facilitate lignin removal and enhance the enzymatic digestion of cellulose. However, lignin always suffers a severe and irreversible condensation. The newly generated C-C bonds dramatically affect its further upgrading. In this study, we used a recyclable hydrotrope (p-Toluenessulfonic acid, p-TsOH) to dissolve lignin under mild condition and stabilized lignin with a quenching agent (formaldehyde, FA) during extraction, achieving both value-added lignin extraction and efficient enzymatic saccharification of cellulose. Approximately 63.7% of lignin was dissolved by 80% (wt. %) p-TsOH with 1.5% FA addition at 80 o C, 30 min. The obtained lignin was characterized by FTIR spectroscopy, TGA, 2D HSQC NMR spectroscopy, and GPC. The results indicated that the extracted lignin exhibited excellent properties, such as light color, a low molecular weight (Mw, 5371 g/mol), and a narrow polydispersity (Mw/Mn, 1.63). The pretreated substrate was converted to ethanol via a quasi-simultaneous saccharification and fermentation process (Q-SSF). After fermentation of 60 h, the ethanol concentration reached 38.7±3.3 g/L which was equivalent to a theoretical ethanol yield of 82.9±2.2% based on the glucan content, while the residual glucose concentration was only 4.69±1.4 g/L. In short, this pretreatment strategy protected lignin to form new C-C linkages and improved the enzymatic saccharification of glucan for high-titer ethanol production.

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Agustin Krisna Wardani ◽  
Aji Sutrisno ◽  
Titik Nur Faida ◽  
Retno Dwi Yustina ◽  
Untung Murdiyatmo

Background. Oil palm trunk (OPT) with highly cellulose content is a valuable bioresource for bioethanol production. To produce ethanol from biomass, pretreatment is an essential step in the conversion of lignocellulosic biomass to fermentable sugars such as glucose and xylose. Several pretreatment methods have been developed to overcome biomass recalcitrance. In this study, the effects of different pretreatment methods such as alkali pretreatment, microwave-alkali, and alkaline peroxide combined with autoclave on the lignocellulosic biomass structure were investigated. Moreover, ethanol production from the treated biomass was performed by simultaneous saccharification and cofermentation (SSCF) under different temperatures, fermentation times, and cell ratios of Saccharomyces cerevisiae NCYC 479 and pentose-utilizing yeast, Pichia stipitis NCYC 1541. Results. Pretreatment resulted in a significant lignin removal up to 83.26% and cellulose released up to 80.74% in treated OPT by alkaline peroxide combined with autoclave method. Enzymatic hydrolysis of treated OPT resulted in an increase in fermentable sugar up to 93.22%. Optimization of SSCF by response surface method showed that the coculture could work together to produce maximum ethanol (1.89%) and fermentation efficiency (66.14%) under the optimized condition. Conclusion. Pretreatment by alkaline peroxide combined with autoclave method and SSCF process could be expected as a promising system for ethanol production from oil palm trunk and various lignocellulosic biomass.

Fermentation ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 310
Nasib Qureshi ◽  
Badal Saha ◽  
Siqing Liu ◽  
Thaddeus Ezeji ◽  
Nancy Nichols

Butanol was produced commercially from cornstarch and sugarcane molasses (renewable resources) until 1983, when production of these plants was forced to cease because of unfavorable economics of production caused in part by escalating prices of these feedstocks. During recent years, the focus of research has been on the use of economically available agricultural biomass and residues and cutting-edge science and technology to make butanol production a commercially viable process again. In this study, we produced butanol from sweet sorghum bagasse (SSB) by employing high concentrations of SSB solids and integrated process technology through which simultaneous saccharification, fermentation, and recovery (SSFR) were conducted as one unit operation. The concentrated SSB (16–22% dry wt. basis or 160–220 gL−1) was used to reduce reactor size and potentially reduce fixed and operational costs. Indeed, ABE productivity and yield of 0.21 gL−1h−1 and 0.39 were obtained, respectively, when 160 gL−1 SSB (16%, dry wt.) was used in the SSFR process. In nonintegrated systems, use of >90 gL−1 solid loading is improbable and has not been done until this study.

2021 ◽  
Vol 7 (12) ◽  
pp. 1038
Hao Ji ◽  
Ke Xu ◽  
Xiameng Dong ◽  
Da Sun ◽  
Libo Jin

Improving the comprehensive utilization of sugars in lignocellulosic biomass is a major challenge for enhancing the economic viability of lignocellulose biorefinement. A robust yeast Pichia kudriavzevii N-X showed excellent performance in ethanol production under high temperature and low pH conditions and was engineered for ᴅ-xylonate production without xylitol generation. The recombinant strain P. kudriavzevii N-X/S1 was employed for sequential production of ᴅ-xylonate and ethanol from ᴅ-xylose, feeding on ᴅ-glucose without pH control in a two-stage strategy of aerobic and shifting micro-aerobic fermentation. Acid-pretreated corncob without detoxification and filtration was used for ᴅ-xylonate production, then simultaneous saccharification and ethanol fermentation was performed with cellulase added at pH 4.0 and at 40 °C. By this strategy, 33.5 g/L ᴅ-xylonate and 20.8 g/L ethanol were produced at yields of 1.10 g/g ᴅ-xylose and 84.3% of theoretical value, respectively. We propose a promising approach for the sequential production of ᴅ-xylonate and ethanol from non-detoxified corncob using a single microorganism.

2021 ◽  
Vol 16 (12) ◽  
pp. 64-71
Jambulingam Kiruthika ◽  
A. Sathya ◽  
T. Sharvika

Bioethanol is a renewable energy source with reduced CO2 emission and a better alternate for fossil fuels. The production of bioethanol using low cost agricultural wastes such as fruits waste always remains a better solution for the present environmental and energy problems. The present study focusses on the production of bioethanol from pineapple peel wastes by simultaneous scarification and fermentation process in a completely eco-friendly manner and economical manner. The fruit wastes are rich sources of sugars and can be utilized for the production of second generation fuel. Initially, cellulase producing potent bacterial isolate was isolated from soil sample collected from fruit market (Uzhavar Santhai), R.S. Puram, Coimbatore district, Tamilnadu, India. Further, the bacterial isolate was identified by 16S rDNA sequencing and the sequence was submitted in GenBank with the accession number MW227436. The phylogenetic tree was constructed and the bacterial isolate was identified as Bacillus cereus strain JK79. Pineapple peel waste was processed, heat pretreated and was utilized for enzymatic saccharification with crude cellulase enzyme to hydrolyze cellulose into simple sugars. The enzyme hydrolyzed content was allowed to undergo fermentation simultaneously (Simultaneous saccharification and fermentation) utilizing Saccharomyces cerevisiae to produce bioethanol. The yield of bioethanol was determined by potassium dichromate method. About 10.07 g/l of bioethanol was obtained by fermenting the enzymatically hydrolyzed pineapple peel waste using Saccharomyces cerevisiae. The production of bioethanol was confirmed by GC-MS.

2021 ◽  
Junfeng Li ◽  
Qifeng Wu ◽  
Zong Ceng ◽  
Aili Wu ◽  
Zhongyong Huang ◽  

Abstract Clarifying key cellulase component that played synergistic roles with lactic acid bacteria (LAB) in fermenting alfalfa lignocellulose into lactic acid (LA) is valuable in low-temperature seasons. Last cut and low dry matter (DM) alfalfa was ensiled by 9 treatments, combinations of cellulase component genes engineered Lactoc. lactis subsp. lactis MG1363 strains (HT2, HT3, HT4, HT5, E1C1, E1B1, and C1B1, separately containing bgl1, cbh2, and egl3 gene were mixed at 1:1:1, 2:1:1, 1:2:1, 1:1:2, 1:1:0, 1:0:1, and 0:1:1), cellulase (EN), and a combination of Lactobacillus plantarum and cellulase (LPEN), and without treatments, as the control, with 4 replicates each. After anaerobic preservation in a silo from late fall through winter (3-20℃) for 140 d, the ensiled alfalfa was sampled and analysed. EN degraded lignocellulose best but the pH was the key limiting factor for lignocellulose saccharification of commercial EN in the simultaneous saccharification and fermentation of LPEN. The optimal combination HT4 caused the fewest disaccharide (1.02 g/kg DM) and the highest conversion of water-soluble carbohydrates (WSC) to LA (170%) and increased LA content to 80.0 g/kg DM maximally since cellobiohydrolase better cooperated with Lactoc. lactis host to ferment lignocellulose into LA than endoglucanase and β-glucosidase. Therefore, strong LA production was approached in HT4 by clarifying key cellulase component played synergistic roles with Lactoc. lactis host. This study could benefit the development of LA production in fermenting lignocellulosic biomass.

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