scholarly journals Alternative Lime Pretreatment of Corn Stover for Second-Generation Bioethanol Production

Agronomy ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 155
Author(s):  
Iria Fírvida ◽  
Pablo G. del Río ◽  
Patricia Gullón ◽  
Beatriz Gullón ◽  
Gil Garrote ◽  
...  
Keyword(s):  
Corn Stover ◽  
Second Generation ◽  
Solid Phase ◽  
Enzymatic Saccharification ◽  
Effect Of Temperature ◽  
Ethanol Conversion ◽  
Second Generation Bioethanol ◽  
Lime Pretreatment ◽  
Simultaneous Saccharification ◽  
Successful Production

In this work, a delignification process, using lime (Ca(OH)2) as an alternative alkali, was evaluated to improve enzymatic saccharification of corn stover cellulose, with the final goal of obtaining second-generation bioethanol. For that, an experimental design was conducted in order to assay the effect of temperature, lime loading, and time on the corn stover fractionation and enzymatic susceptibility of cellulose. Under conditions evaluated, lime pretreatment was selective for the recovery of cellulose (average of 91%) and xylan (average of 75.3%) in the solid phase. In addition, operating in mild conditions, a delignification up to 40% was also attained. On the other hand, a maximal cellulose-to-glucose conversion (CGCMAX) of 89.5% was achieved using the solid, resulting from the treatment carried out at 90 °C for 5 h and lime loading of 0.4 g of Ca(OH)2/g of corn stover. Finally, under selected conditions of pretreatment, 28.7 g/L (or 3.6% v/v) of bioethanol was produced (corresponding to 72.4% of ethanol conversion) by simultaneous saccharification and fermentation. Hence, the process, based on an alternative alkali proposed in this work, allowed the successful production of biofuel from the important and abundant agro-industrial residue of corn stover.

Ionic Liquid 1-Butyl-3-Methylimidazolium Chloride/FeCl3 Pretreatment of Sugarcane Residue for Second Generation Bioethanol Production

2013 ◽  
Vol 275-277 ◽  
pp. 1662-1665 ◽  
Author(s):  
Qiang Li ◽  
Juan Juan Fei ◽  
Xu Ding Gu ◽  
Geng Sheng Ji ◽  
Yang Liu ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Enzymatic Hydrolysis ◽  
Low Temperature ◽  
Second Generation ◽  
Reducing Sugars ◽  
Enzymatic Saccharification ◽  
Cellulosic Biomass ◽  
Candida Shehatae ◽  
Second Generation Bioethanol ◽  
Temperature Pretreatment

This study aims to establish a natural cellulosic biomass pretreatment process using ionic liquid (IL) for efficient enzymatic hydrolysis and second generation bioethanol. The IL 1-Butyl-3-methylimidazolium Chloride/FeCl3 ([Bmim]Cl/FeCl3) was selected in view of its low temperature pretreatment ability and the potential of accelerating enzymatic hydrolysis, and it could be recyclable. The yield of reducing sugars from sugarcane residue pretreated with this IL at 80 oC for 1 h reached 46.8% after being enzymatically hydrolyzed for 24 h. Sugarcane residue regenerated were hydrolyzed more easily than that treated with water. The fermentability of the hydrolyzates, obtained after enzymatic saccharification of the regenerated sugarcane residue, was transformed into bioethanol using Candida shehatae. This microbe could absorb glucose and xylose efficiently, and the ethanol production was 0.38 g/g glucose within 30 h fermentation. In conclusion, the metal ionic liquid pretreatment in low temperature shows promise as pretreatment solvent for natural biomass.

Expression of serpins by Clostridium thermocellum and simultaneous saccharification of lignocellulosic biomass to enhance ethanol production

BioResources ◽  
2020 ◽  
Vol 15 (4) ◽  
pp. 8662-8676
Author(s):  
Maria Mushtaq ◽  
Muhammad Javaid Asad ◽  
Muhammad Zeeshan Hyder ◽  
Syed Muhammad Saqlan Naqvi ◽  
Saad Imran Malik ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Wheat Straw ◽  
Corn Stover ◽  
Rice Straw ◽  
Clostridium Thermocellum ◽  
Ethanol Yield ◽  
Biofuel Production ◽  
Yeast Fermentation ◽  
Second Generation Bioethanol ◽  
Simultaneous Saccharification

Utilization of biomass for production of second generation bioethanol was considered as a way to reduce burdens of fossil fuel in Pakistan. The materials wheat straw, rice straw, cotton stalk, corn stover, and peel wastes were used in this experiment. Various parameters, such as acidic and alkali pretreatment, enzymatic hydrolysis by cellulases, and effect of proteases inhibitors on ethanol production, were examined. Fermentation was completed by the yeasts Saccharomyces cerevisiae and Clostridium thermocellum separately, and their ethanol production were compared and maximum ethanol yield was obtained with wheat straw i.e.,11.3 g/L by S. cerevisiae and 8.5 g/L by C. thermocellum. Results indicated that a higher quantity of sugar was obtained from wheat straw (19.6 ± 1.6 g/L) followed by rice straw (17.6 ± 0.6 g/L) and corn stover (16.1 ± 0.9 g/L) compared to the other evaluated biomass samples. A higher yield of ethanol (11.3 g/L) was observed when a glucose concentration of 21.7 g/L was used, for which yeast fermentation efficiency was 92%. Results also revealed the increased in ethanol production (93%) by using celluases in combination with recombinant Serine protease inhibitors from C. thermocellum. It is expected that the use of recombinant serpins with cellulases will play a major role in the biofuel production by using agricultural biomass. This will also help in the economics of the biofuel.

scholarly journals A Whole-Slurry Fermentation Approach to High-Solid Loading for Bioethanol Production from Corn Stover

Agronomy ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1790 ◽  
Author(s):  
Pablo G. del Río ◽  
Patricia Gullón ◽  
F.R. Rebelo ◽  
Aloia Romaní ◽  
Gil Garrote ◽  
...  
Keyword(s):  
Corn Stover ◽  
Crop Residue ◽  
Solid Phase ◽  
Solid Loading ◽  
High Solid ◽  
High Solid Loading ◽  
Second Generation Bioethanol ◽  
Liquid Phases ◽  
Solid Phases ◽  
Whole Slurry

Corn stover is the most produced byproduct from maize worldwide. Since it is generated as a residue from maize harvesting, it is an inexpensive and interesting crop residue to be used as a feedstock. An ecologically friendly pretreatment such as autohydrolysis was selected for the manufacture of second-generation bioethanol from corn stover via whole-slurry fermentation at high-solid loadings. Temperatures from 200 to 240 °C were set for the autohydrolysis process, and the solid and liquid phases were analyzed. Additionally, the enzymatic susceptibility of the solid phases was assessed to test the suitability of the pretreatment. Afterward, the production of bioethanol from autohydrolyzed corn stover was carried out, mixing the solid with different percentages of the autohydrolysis liquor (25%, 50%, 75%, and 100%) and water (0% of liquor), from a total whole slurry fermentation (saving energy and water in the liquid–solid separation and subsequent washing of the solid phase) to employing water as only liquid medium. In spite of the challenging scenario of using the liquor fraction as liquid phase in the fermentation, values between 32.2 and 41.9 g ethanol/L and ethanol conversions up to 80% were achieved. This work exhibits the feasibility of corn stover for the production of bioethanol via a whole-slurry fermentation process.

Plant cell walls to ethanol

2012 ◽  
Vol 442 (2) ◽  
pp. 241-252 ◽  
Author(s):  
Douglas B. Jordan ◽  
Michael J. Bowman ◽  
Jay D. Braker ◽  
Bruce S. Dien ◽  
Ronald E. Hector ◽  
...  
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Second Generation ◽  
Consolidated Bioprocessing ◽  
Enzymatic Saccharification ◽  
Crystalline Cellulose ◽  
Plant Cell Walls ◽  
Second Generation Bioethanol ◽  
Single Organism ◽  
The Cost

Conversion of plant cell walls to ethanol constitutes second generation bioethanol production. The process consists of several steps: biomass selection/genetic modification, physiochemical pretreatment, enzymatic saccharification, fermentation and separation. Ultimately, it is desirable to combine as many of the biochemical steps as possible in a single organism to achieve CBP (consolidated bioprocessing). A commercially ready CBP organism is currently unreported. Production of second generation bioethanol is hindered by economics, particularly in the cost of pretreatment (including waste management and solvent recovery), the cost of saccharification enzymes (particularly exocellulases and endocellulases displaying kcat ~1 s−1 on crystalline cellulose), and the inefficiency of co-fermentation of 5- and 6-carbon monosaccharides (owing in part to redox cofactor imbalances in Saccharomyces cerevisiae).

scholarly journals Pretreatment of Corn Stover Using an Extremely Low-Liquid Ammonia (ELLA) Method for the Effective Utilization of Sugars in Simultaneous Saccharification and Fermentation (SSF) of Ethanol

Fermentation ◽  
2021 ◽  
Vol 7 (3) ◽  
pp. 191
Author(s):  
Tin Diep Trung Le ◽  
Vi Phuong Nguyen Truong ◽  
My Thi Tra Ngo ◽  
Tae Hyun Kim ◽  
Kyeong Keun Oh
Keyword(s):  
Corn Stover ◽  
Liquid Ammonia ◽  
Elevated Temperatures ◽  
Simultaneous Saccharification And Fermentation ◽  
Aqueous Ammonia ◽  
Ethanol Yield ◽  
Enzymatic Saccharification ◽  
Extended Period ◽  
Pretreatment Conditions ◽  
Simultaneous Saccharification

Extremely low-liquid ammonia (ELLA) pretreatment using aqueous ammonia was investigated in order to enhance the enzymatic saccharification of corn stover and subsequent ethanol production. In this study, corn stover was treated with an aqueous ammonia solution at different ammonia loading rates (0.1, 0.2, and 0.3 g NH3/g biomass) and various liquid-to-solid (L/S) ratios (0.55, 1.12, and 2.5). The ELLA pretreatment was conducted at elevated temperatures (90–150 °C) for an extended period (24–120 h). Thereafter, the pretreated material was saccharified by enzyme digestion and subjected to simultaneous saccharification and fermentation (SSF) tests. The effects of key parameters on both glucan digestibility and xylan digestibility were analyzed using analysis of variance (ANOVA). Under optimal pretreatment conditions (L/S = 2.5, 0.1 g-NH3/g-biomass, 150 °C), 81.2% glucan digestibility and 61.1% xylan digestibility were achieved. The highest ethanol yield achieved on the SSF tests was 85.4%. The ethanol concentration was 14.5 g/L at 96 h (pretreatment conditions: liquid-to-solid ratio (L/S) = 2.5, 0.1 g-NH3/g-biomass, 150 °C, 24 h. SSF conditions: microorganism Saccharomyces cerevisiae (D5A), 15 FPU/g-glucan, CTech2, 3% w/v glucan, 37 °C, 150 rpm).

scholarly journals Waste-Based Second-Generation Bioethanol: A Solution for Future Energy Crisis

2021 ◽  
Vol 11 (1) ◽  
pp. 275-285
Author(s):  
Yasindra Sandamini Chandrasiri ◽  
Lakshika Iroshani Weerasinghe ◽  
Tharindu Madusanka ◽  
Pathmalal Manage
Keyword(s):  
Second Generation ◽  
Solid Phase ◽  
Energy Crisis ◽  
Bioethanol Production ◽  
Bacillus Sp ◽  
Bacterial Strains ◽  
Promising Alternative ◽  
Paper Waste ◽  
Second Generation Bioethanol ◽  
Achromobacter Sp

The demand for more environmentally friendly alternative renewable fuels is growing as fossil fuel resources are depleting significantly. Consequently, bioethanol has attracted interest as a potentially viable fuel. The key steps in second-generation bioethanol production include pretreatment, saccharification, and fermentation. The present study employed simultaneous saccharification and fermentation (SSF) of cellulose through bacterial pathways to generate second-generation bioethanol utilizing corncobs and paper waste as lignocellulosic biomass. Mechanical and chemical pretreatments were applied to both biomasses. Then, two bacterial strains, Bacillus sp. and Norcadiopsis sp., hydrolysed the pretreated biomass and fermented it along with Achromobacter sp., which was isolated and characterized from a previous study. Bioethanol production followed by 72 h of biomass hydrolysis employing Bacillus sp. and Norcadiopsis sp., and then 72 h of fermentation using Achromobacter sp. Using solid phase micro extraction combined with GCMS the ethanol content was quantified. SSF of alkaline pretreated paper waste hydrolysed by Bacillus sp. following the fermentation by Achromobacter sp. showed the maximum ethanol percentage of 0.734±0.154. Alkaline pretreated corncobs hydrolyzed by Norcadiopsis sp. yielded the lowest ethanol percentage of 0.155±0.154. The results of the study revealed that paper waste is the preferred feedstock for generating second-generation bioethanol. To study the possible use of ethanol-diesel blends as an alternative biofuel E2, E5, E7, and E10 blend emulsions were prepared mixing commercially available diesel with ethanol. The evaluated physico-chemical characteristics of the ethanol-diesel emulsions fulfilled the Ceypetco requirements except for the flashpoint revealing that the lower ethanol-diesel blends are a promising alternative to transport fuels. As a result, the current study suggests that second generation bioethanol could be used as a renewable energy source to help alleviate the energy crisis..

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