Optimized Production of Bioethanol by Fermentation of Acid Hydrolyzed-Corn Stover Employing Saccharomyces Cerevisiae Yeast Strain (original) (raw)
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Alkaline pretreatment and enzymatic hydrolysis of corn stover for bioethanol production
Research, Society and Development, 2021
The demand for ethanol in Brazil is growing. However, although the country is one of the largest producers of this fuel, it is still necessary to diversify the production matrix. In that regard, studies with different raw materials are needed, mainly the use of low cost and high available wastes such as lignocellulosic residues from agriculture. Therefore, this study aimed to analyze the bioethanol production from corn stover. An alkaline pretreatment (CaO) was carried out, followed by enzymatic hydrolysis (Cellic Ctec2 and Cellic Htec2) to obtain fermentable sugars. The best experimental condition for the pretreatment and hydrolysis steps resulted in a solution with 0.31 gsugar∙gbiomass-1. Then, the fermentation was performed by the industrial strain of Saccharomyces cerevisiae (PE-2) and by the wild yeast strain Wickerhamomyces sp. (UFFS-CE-3.1.2). The yield obtained was 0.38 gethanol∙gdry biomass-1 was, demonstrating the potential of this process for bioethanol production.
Effects of Process Variables on the Fermentation of Corn Stover: A Review
Bioethanol production involves the fermentation of feedstock from raw lignocellulosic biomass to chemical fuel via biological routes. Response Surface Methodology (RSM) was considered as a tool to represent the optimization of ethanol production as a function of the fermentation independent variables i.e. fermentation temperature and time, pH of the hydrolysate and yeast concentration (Saccharomyces cerevisiae), in a batch fermentation. The effect of fermentation independent variables and their combined interactions on the production of bioethanol by Saccharomyces cerevisiae was evaluated to improve the bioethanol fermentation performance. The interactions of the fermentation independent variables using RSM indicated that the highest yield could be reached near the center point of the operating conditions. The range of temperatures, time and pH were established to optimize the fermentation condition by RSM which could save experiment times and cost. Introduction Bioethanol productio...
Industrial Crops and Products, 2013
Corn stover used in this study contained 37.0 ± 0.4% cellulose, 31.3 ± 0.6% hemicellulose and 17.8 ± 0.2% lignin on dry basis. Hydrothermal pretreatment and enzymatic saccharification were evaluated for conversion of corn stover cellulose and hemicellulose to fermentable sugars. Under the optimum conditions of hydrothermal pretreatment of corn stover (10%, w/v; 200 • C; 5 min) and enzymatic saccharification (45 • C, pH 5.0, 72 h), a total of 550 ± 5 mg of fermentable sugars was obtained per g corn stover which is equivalent to 72% of theoretical sugar yield. The corn stover hydrolyzate was fermented without any detoxification by recombinant Escherichia coli strain FBR 5 at pH 6.5 and 37 • C for 74 h to produce 20.9 ± 0.5 g ethanol from 42.8 ± 1.7 g sugars per L with a yield of 0.49 g ethanol per g available sugars and 0.27 g ethanol per g corn stover which is equivalent to 68.7% of theoretical ethanol yield from corn stover. This is the first report on the production of ethanol from hydrothermally pretreated corn stover by the recombinant bacterium.
Fuel, 2009
The simultaneous enzymatic saccharification and fermentation (SSF) of corn meal using immobilized cells of Saccharomyces cerevisiae var. ellipsoideus yeast in a batch system was studied. The yeast cells were immobilized in Ca-alginate by electrostatic droplet generation method. The process kinetics was assessed and determined and the effect of addition of various yeast activators (mineral salts: ZnSO 4 Á 7H 2 O and MgSO 4 Á 7H 2 O, and vitamins: Ca-pantothenate, biotin and myo-inositol) separately or mixed, was investigated. Taking into account high values of process parameters (such as ethanol concentration, ethanol yield, percentage of the theoretical ethanol yield, volumetric productivity and utilized glucose) and significant energy savings the SSF process was found to be superior compared to the SHF process. Further improvement in ethanol production was accomplished with the addition of mineral salts as yeast activators which contributed to the highest increase in ethanol production. In this case, the ethanol concentration of 10.23% (w/w), percentage of the theoretical ethanol yield of 98.08%, the ethanol yield of 0.55 g/g and the volumetric productivity of 2.13 g/lÁh were obtained.
Temperature Optimization for Bioethanol Production from Corn Cobs Using Mixed Yeast Strains
OnLine Journal of Biological Sciences, 2010
Problem statement: Dilute sulphuric acid and enzymatic hydrolysis methods were used for sugar extraction. Xylose and glucose sugars were obtained from corn cobs. Approach: Acid hydrolysis of corn cobs gave higher amount of sugars than enzymatic hydrolysis. Results: The results showed that optimal temperature and time for sugar fermentation were approximately 25°C and 50 h by two yeast strains (S. cerevisiae and P. Stipitis) respectively. At 20 and 40°C, less bioethanol was produced. Bioethanol produced at 25°C was 11.99 mg mL −1 , while at 40 and 20°C were 2.50 and 6.40 mg mL −1 respectively. Conclusion/Recommendations: Data obtained revealed that xylose level decreased from 27.87-3.92 mg mL −1 during the first 50 h of fermentation and complete metabolism of glucose was observed during this time. Xylose and bioethanol levels remained constant after 50 h. Varying the temperature of the fermentation process improves the effective utilization of corn cobs sugars for bioethanol production can be achieved.
Effect of Acid Concentration on the Yield of Bio-ethanol Produced from Corncobs
World Journal of Applied Chemistry, 2019
The Rising energy requirements and atmospheric contaminations by combustion of gases and conventional fuel, has opened avenues for new, safe, effective and more accessible energy sources. Corn is one of the richest sources for the production of ethanol. This research looked the effect of concentration of sulphuric acid on the yield of bio-ethanol produced from the lingocellulosic material corncob which is an alternative over food derived ethanol, consumption of crude oil and environmental pollution. The main objective of this study is to know the best acid concentration to that can used during acid hydrolysis for the production of ethanol from the cellulosic content of corncobs. In this study, different condition was examined as to access their effect for optimum ethanol production. The method used was acid hydrolysis of corncobs with varied acid molarities of 0.4M, 0.6M, 0.8M and 1M. The UV/visible spectrophotometer of 1M H 2 SO 4 has the highest absorbance of 0.447, followed by 0.8M (0.368), 0.6M (0.292) and 0.4M (0.253). The result obtained from the physical parameters measured for each different concentration after fermentation processes of the bio ethanol produced, 1M H 2 SO 4 of the corncobs prepared produced the highest percentage yield (55.5%) of the bio ethanol followed by 0.8M (50.5%), 0.6M (47%) and 0.4M (42%) which was the lowest yield. This has shown that acid hydrolysis at 1M H 2 SO 4 with moderate yeast concentration 3g/20cm 3 at room temperature and atmosphere pressure can be used to improve the production of bio ethanol.
Optimization of Ethanol Production from Enzymatic Hydrolysate of Maize Stover
Advances in Recycling & Waste Management, 2016
For efficient bioethanol production from maize stover, fermentation of glucose and xylose both was attempted using Saccharomyces cerevisiae and Pichia stipitis sequentially from enzymatic hydrolysate of mild alkali treated maize stover. Enzymatic saccharification of mild alkali treated maize stover at high substrate (30%) loading using 13.0 FPU/g commercial cellulase (MAPs 450) and 74.42 U/g crude β-xylosidase (Inhouse produced) after 36 h, yielded 161.32 mg ml-1 reducing sugars. Ethanol production was optimized employing response surface methodology. Under optimized conditions viz. 5% glucose, 14.55% inoculum and Time 35.51 h; 90.65% glucose was utilized and produced 18.93 g l-1 ethanol with 0.53 g l-1 h-1 productivity by Saccharomyces cerevisiae NCIM 3524. Further attempts were made to produce ethanol from xylose present in enzymatic hydrolysate using Pichia stipitis NCIM 3497. However, xylose conversion was not satisfactory as only 71% xylose was utilized.
Cellulose Chemistry and Technology, 2023
The present study was carried out to optimise the simultaneous saccharification and fermentation process for bioethanol production from corn cobs. Ten (10) different corn genotypes (hybrids) were characterized in terms of chemical composition, including total solid, moisture, cellulose, hemicelluloses, lignin and ash contents. Among different corn genotypes, milled cobs of corn genotype PMH10 were found to have significantly high cellulose (34.05%) and low lignin content (11.87%). With sodium hydroxide pretreatment, the relative proportion of cellulose (56.70%) increased, while that of hemicelluloses, lignin and ash substantially decreased (11.87, 8.61 and 0.6%) in the treated cob residues. The optimization of the simultaneous saccharification and fermentation (SSF) process of pretreated cob residues through response surface methodology showed that maximum ethanol concentration of 3.64 mg/mL could be achieved when SSF was performed at 28.58 FPU/g enzyme dosage, solid loading of 14.95% and yeast inoculum of 9.56%.
2017
Purwoko Tj, Sari SLA, Mahadjoeno E, Sunarto. 2017. Bioethanol production from rice and corn husks after enzymatic and microbes hydrolysis and yeast fermentation. Bioteknologi 14: 19-23. Bioethanol is a renewable resource that can be produced from fermented cellulosic biomass. The use of lignocellulosic materials from agricultural wastes provides a low-cost fermentative substrate. Lignocellulosic ethanol production involves acid or enzymatic hydrolysis. The enzymatic hydrolysis is high cost however in environmental issue this step is favorable. The purpose of this research was to compare bioethanol production after microbes and cellulosic enzymes hydrolysis following yeast Saccharomyces cerevisiae fermentation from rice and corn husks.The rice and corn husks (1 kg) were each suspended into water until the volumes reached 5 L. The sample mixtures were treated with 2.5 mg/L cellulases, 5 g/L multienzymes, and 5 mL/L EM4 respectively. The mixtures were stirred for 24 hours at pH 5.7 and...