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.

PRODUCTION OF BIOFUEL FROM WASTE LIGNOCELLULOSIC BIOMASS MATERIALS BASED ON ENERGY SAVING VIEWPOINT

2012 ◽  
Vol 06 ◽  
pp. 715-720
Author(s):  
Maki Takano ◽  
Kazuhiro Hoshino
Keyword(s):  
Lignocellulosic Biomass ◽  
Rice Straw ◽  
Steam Explosion ◽  
Simultaneous Saccharification And Fermentation ◽  
Biofuel Production ◽  
Fermentable Sugars ◽  
Renewable Material ◽  
Suitable Combination ◽  
Biomass Materials ◽  
Simultaneous Saccharification

To develop biofuel production from waste lignocellulosic biomass materials the rice straw was selected one of renewable material and the degradation condition about pretreatment and enzymatic hydrolysis to obtain effectively fermentable sugars was investigated. Rice straw was pretreated by five kinds of methods and then the components ratio of rice straw was examined. First, the steam explosion was selected based on the degradability and the requirement energy. In addition, the best suitable combination of two cellulases to effective and economical hydrolyze was determined from the degradability of these pretreated rice straws. In the simultaneous saccharification and fermentation of the steam explosion rice straw by combining cellulase cocktail and a novel fermenting fungus, 13.2 g/L ethanol was able to product for 96 h.

scholarly journals LAND-USE AND GREENHOUSE GAS IMPLICATIONS OF BIOFUELS: ROLE OF TECHNOLOGY AND POLICY

2012 ◽  
Vol 03 (03) ◽  
pp. 1250013 ◽  
Author(s):  
XIAOGUANG CHEN ◽  
HAIXIAO HUANG ◽  
MADHU KHANNA
Keyword(s):  
Land Use ◽  
Ghg Emissions ◽  
Carbon Price ◽  
Price Policy ◽  
Biofuel Production ◽  
Tax Credit ◽  
Cellulosic Biofuels ◽  
Cellulosic Biofuel ◽  
The U.S ◽  
Ghg Savings

This paper examines the changes in land use in the U.S. likely to be induced by biofuel and climate policies and the implications of these policies for greenhouse gas (GHG) emissions over the 2007–2022 period. The policies considered here include a modified Renewable Fuel Standard (RFS) by itself as well as combined with a cellulosic biofuel tax credit or a carbon price policy. We use a dynamic, spatial, multi-market equilibrium model, Biofuel and Environmental Policy Analysis Model (BEPAM), to endogenously determine the effects of these policies on cropland allocation, food and fuel prices, and the mix of first- and second-generation biofuels. We find that the RFS could be met by diverting 6% of cropland for biofuel production and would result in corn prices increasing by 16% in 2002 relative to the business-as-usual baseline. The reduction in GHG emissions in the U.S. due to the RFS is about 2%; these domestic GHG savings can be severely eroded by emissions due to indirect land-use changes and the increase in gasoline consumption in the rest of the world. Supplementing the RFS with a carbon price policy or a cellulosic biofuel tax credit induces a switch away from corn ethanol to cellulosic biofuels and achieves the mandated level of biofuel production with a smaller adverse impact on crop prices. These supplementary policies enhance the GHG savings achieved by the RFS alone, although through different mechanisms; greater production of cellulosic biofuels with the tax credit but larger reduction in fossil fuel consumption with a carbon tax.

scholarly journals Alkali Pretreatment and Enzymatic Hydrolysis of Australian Timber Mill Sawdust for Biofuel Production

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Raymond Martin Trevorah ◽  
Maazuza Z. Othman
Keyword(s):  
Enzymatic Hydrolysis ◽  
Simultaneous Saccharification And Fermentation ◽  
Glucose Production ◽  
Biofuel Production ◽  
Alkali Pretreatment ◽  
Ethanol Yields ◽  
The Impact ◽  
Hydrolysis Of ◽  
Potential Use ◽  
Simultaneous Saccharification

This study investigated the potential use of alkali pretreatment of sawdust from Australian timber mills to produce bioethanol. Sawdust was treated using 3–10% w/w NaOH at temperatures of 60, 121, and −20°C. Two pathways of production were trialled to see the impact on the bioethanol potential, enzymatic hydrolysis for glucose production, and simultaneous saccharification and fermentation (SSF) for ethanol production. The maximum yields obtained were at 121°C and −20°C using 7% NaOH, with 29.3% and 30.6% ethanol yields after 0.5 and 24 hr, respectively, these treatments yielded 233% and 137% increase from the 60°C counter parts. A notable trend of increased ethanol yields with increased NaOH concentration was observed for samples treated at 60°C; for example, samples treated using 10% NaOH produced 1.92–2.07 times more than those treated using 3% NaOH. FTIR analysis showed reduction in crystallinity correlating with increased ethanol yields with the largest reduction in crystallinity in the sample treated at −20°C for 24 hr with 7% NaOH.

scholarly journals Construction and optimization of a heterologous pathway for protocatechuate catabolism inEscherichia colienables rapid bioconversion of model lignin monomers

2017 ◽  
Author(s):  
Sonya M. Clarkson ◽  
Donna M. Kridelbaugh ◽  
James G. Elkins ◽  
Adam M. Guss ◽  
Joshua K. Michener
Keyword(s):  
Escherichia Coli ◽  
Sole Source ◽  
Biofuel Production ◽  
List Type ◽  
Cellulosic Biofuels ◽  
E Coli ◽  
Gene Pathway ◽  
Cellulosic Biofuel ◽  
Fuels And Chemicals ◽  
Heterologous Pathway

AbstractCellulosic biofuel production yields a substantial lignin byproduct stream that currently has few applications. Biological conversion of lignin compounds into chemicals and fuels has the potential to improve the economics of cellulosic biofuels, but few microbes are able both to catabolize lignin and generate valuable products. WhileEscherichia colihas been engineered to produce a variety of fuels and chemicals, it is incapable of catabolizing most aromatic compounds. Therefore, we have engineeredE. colito catabolize a model lignin monomer, protocatechuate, as the sole source of carbon and energy, via heterologous expression of a nine-gene pathway fromPseudomonas putidaKT2440. We next used experimental evolution to select for mutations that increased growth with PCA more than two-fold. Increasing the strength of a single ribosome binding site in the heterologous pathway was sufficient to recapitulate the increased growth. After optimization of the core pathway, we extended the pathway to enable catabolism of a second model compound, 4-hydroxybenzoate. These engineered strains will be useful platforms to discover, characterize, and optimize pathways for lignin bioconversions.HighlightsA heterologous pathway for PCA catabolism was transferred to Escherichia coli.Evolution identified a mutation that increased growth with PCA by 2.5-fold.Optimization plus further engineering allowed efficient catabolism of 4-HB

Selection of thermotolerant yeasts for simultaneous saccharification and fermentation (SSF) of cellulose to ethanol

1991 ◽  
Vol 28-29 (1) ◽  
pp. 307-315 ◽  
Author(s):  
I. Ballesteros ◽  
M. Ballesteros ◽  
A. CabaÑas ◽  
J. Carrasco ◽  
C. MartÍn ◽  
...  
Keyword(s):  
Simultaneous Saccharification And Fermentation ◽  
Thermotolerant Yeasts ◽  
Simultaneous Saccharification ◽  
Selection Of

scholarly journals Application of Pichia kudriavzevii NBRC1279 and NBRC1664 to Simultaneous Saccharification and Fermentation for Bioethanol Production

Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 83
Author(s):  
Hironaga Akita ◽  
Tetsuya Goshima ◽  
Toshihiro Suzuki ◽  
Yuya Itoiri ◽  
Zen-ichiro Kimura ◽  
...  
Keyword(s):  
Simultaneous Saccharification And Fermentation ◽  
Draft Genome ◽  
Enzymatic Saccharification ◽  
Japanese Cedar ◽  
Biofuel Production ◽  
Venn Diagram ◽  
Genome Comparison ◽  
Bioethanol Production ◽  
Pichia Kudriavzevii ◽  
Simultaneous Saccharification

Simultaneous saccharification and fermentation (SSF) is capable of performing enzymatic saccharification and fermentation for biofuel production in a single vessel. Thus, SSF has several advantages such as simplifying the manufacturing process, operating easily, and reducing energy input. Here, we describe the application of Pichia kudriavzevii NBRC1279 and NBRC1664 to SSF for bioethanol production. When each strain was incubated for 144 h at 35 °C with Japanese cedar particles, the highest ethanol concentrations were reached 21.9 ± 0.50 g/L and 23.8 ± 3.9 g/L, respectively. In addition, 21.6 ± 0.29 g/L and 21.3 ± 0.21 g/L of bioethanol were produced from Japanese eucalyptus particles when each strain was incubated for 144 h at 30 °C. Although previous methods require pretreatment of the source material, our method does not require pretreatment, which is an advantage for industrial use. To elucidate the different characteristics of the strains, we performed genome sequencing and genome comparison. Based on the results of the eggNOG categories and the resulting Venn diagram, the functional abilities of both strains were similar. However, strain NBRC1279 showed five retrotransposon protein genes in the draft genome sequence, which indicated that the stress tolerance of both strains is slightly different.

Production of Bioethanol from Rice Straw Assisted by Cellulosic Enzyme Oyster Mushroom Stem Using Simultaneous Saccharification and Fermentation (SSF)

2019 ◽  
pp. 193-199
Author(s):  
Tatang Shabur Julianto ◽  
M. Arsyik Kurniawan S ◽  
Ikhwan Arifin
Keyword(s):  
Rice Straw ◽  
Alternative Energy ◽  
Fossil Fuels ◽  
Simultaneous Saccharification And Fermentation ◽  
Agricultural Waste ◽  
Oyster Mushroom ◽  
Enzyme Extract ◽  
Fermentation Time ◽  
Cellulase Enzyme ◽  
Simultaneous Saccharification

Bioethanol is an alternative energy source to replace fossil fuels that can be produced from agricultural waste such as rice straw. The fermentation process can help hydrolyze lignocellulosic compounds in rice straw into simple sugars and convert them into bioethanol. This study aims to determine the effect of fermentation time and the amount of intracellular cellulase enzyme extract from oyster mushroom stem on the levels of biethanol produced. The method used in making bioethanol is Simultaneous Saccharification and Fermentation (SSF). The bioethanol produced was then analyzed by gas chromatography and UV-Vis spectrophotometer. The result showed that the highest level of bioethanol was 14.52% obtained at 10 days fermentation time and the amount  of cellulase enzyme extract was 25 mL.

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