Simultaneous saccharification and fermentation and economic evaluation of ultrasonic and jet cooking pretreatment of corn slurry

2011 ◽  
Vol 27 (6) ◽  
pp. 1561-1569 ◽  
Author(s):  
Melissa Montalbo-Lomboy ◽  
Samir Kumar Khanal ◽  
Johannes Hans van Leeuwen ◽  
David Raj Raman ◽  
David Grewell
Keyword(s):  
Economic Evaluation ◽  
Simultaneous Saccharification And Fermentation ◽  
Jet Cooking ◽  
Simultaneous Saccharification

scholarly journals Cellulosic biofuel production using emulsified simultaneous saccharification and fermentation (eSSF) with conventional and thermotolerant yeasts

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Shannon M. Hoffman ◽  
Maria Alvarez ◽  
Gilad Alfassi ◽  
Dmitry M. Rein ◽  
Sergio Garcia-Echauri ◽  
...  
Keyword(s):  
Simultaneous Saccharification And Fermentation ◽  
Agricultural Waste ◽  
Biofuel Production ◽  
Cellulosic Biofuels ◽  
Processing Times ◽  
Cellulosic Biofuel ◽  
Thermotolerant Yeasts ◽  
Rapid Hydrolysis ◽  
Dedicated Energy Crops ◽  
Simultaneous Saccharification

Abstract Background Future expansion of corn-derived ethanol raises concerns of sustainability and competition with the food industry. Therefore, cellulosic biofuels derived from agricultural waste and dedicated energy crops are necessary. To date, slow and incomplete saccharification as well as high enzyme costs have hindered the economic viability of cellulosic biofuels, and while approaches like simultaneous saccharification and fermentation (SSF) and the use of thermotolerant microorganisms can enhance production, further improvements are needed. Cellulosic emulsions have been shown to enhance saccharification by increasing enzyme contact with cellulose fibers. In this study, we use these emulsions to develop an emulsified SSF (eSSF) process for rapid and efficient cellulosic biofuel production and make a direct three-way comparison of ethanol production between S. cerevisiae, O. polymorpha, and K. marxianus in glucose and cellulosic media at different temperatures. Results In this work, we show that cellulosic emulsions hydrolyze rapidly at temperatures tolerable to yeast, reaching up to 40-fold higher conversion in the first hour compared to microcrystalline cellulose (MCC). To evaluate suitable conditions for the eSSF process, we explored the upper temperature limits for the thermotolerant yeasts Kluyveromyces marxianus and Ogataea polymorpha, as well as Saccharomyces cerevisiae, and observed robust fermentation at up to 46, 50, and 42 °C for each yeast, respectively. We show that the eSSF process reaches high ethanol titers in short processing times, and produces close to theoretical yields at temperatures as low as 30 °C. Finally, we demonstrate the transferability of the eSSF technology to other products by producing the advanced biofuel isobutanol in a light-controlled eSSF using optogenetic regulators, resulting in up to fourfold higher titers relative to MCC SSF. Conclusions The eSSF process addresses the main challenges of cellulosic biofuel production by increasing saccharification rate at temperatures tolerable to yeast. The rapid hydrolysis of these emulsions at low temperatures permits fermentation using non-thermotolerant yeasts, short processing times, low enzyme loads, and makes it possible to extend the process to chemicals other than ethanol, such as isobutanol. This transferability establishes the eSSF process as a platform for the sustainable production of biofuels and chemicals as a whole.

Production and optimization of cellulase from agricultural waste and its application in bioethanol production by simultaneous saccharification and fermentation

2016 ◽  
Vol 27 (1) ◽  
pp. 22-35 ◽  
Author(s):  
Elsa Cherian ◽  
M. Dharmendira Kumar ◽  
G. Baskar
Keyword(s):  
Design Methodology ◽  
Simultaneous Saccharification And Fermentation ◽  
Agricultural Waste ◽  
Cellulase Production ◽  
Reducing Sugar ◽  
Bioethanol Production ◽  
Corn Cob ◽  
Content Type ◽  
Optimized Conditions ◽  
Simultaneous Saccharification

Purpose – The purpose of this paper is to optimize production of cellulase enzyme from agricultural waste by using Aspergillus fumigatus JCF. The study also aims at the production of bioethanol using cellulase and yeast. Design/methodology/approach – Cellulase production was carried out using modified Mandel’s medium. The optimization of the cellulase production was carried out using Plackett-Burman and Response surface methodology. Bioethanol production was carried out using simultaneous saccharification and fermentation. Findings – Maximum cellulase production at optimized conditions was found to be 2.08 IU/ml. Cellulase was used for the saccharification of three different feed stocks, i.e. sugar cane leaves, corn cob and water hyacinth. Highest amount of reducing sugar was released was 29.1 gm/l from sugarcane leaves. Sugarcane leaves produced maximum bioethanol concentration of 9.43 g/l out of the three substrates studied for bioethanol production. Originality/value – The present study reveals that by using the agricultural wastes, cellulase production can be economically increased thereby bioethanol production.

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