Improvement in Ethanol Yield from Lignocellulo-Starch Biomass using Saccharomyces cerevisiae alone or its Co-culture with Scheffersomyces stipitis

2020 ◽  
Vol 9 (1) ◽  
pp. 57-76
Author(s):  
Madhanamohanan G. Mithra ◽  
Gouri Padmaja
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Relative Advantage ◽  
Vegetable Crops ◽  
Fed Batch ◽  
Scheffersomyces Stipitis ◽  
Separate Hydrolysis And Fermentation ◽  
Ethanol Yields ◽  
Sugar Levels

Background: Literature on ethanol production from Lignocellulo-Starch Biomass (LCSB) containing starch besides cellulose and hemicellulose, is scanty. Fed-Batch Separate Hydrolysis And Fermentation (F-SHF) was earlier found more beneficial than Fed-Batch Simultaneous Saccharification and Fermentation (F-SSF). Objective: The study aimed at modification of the saccharification and fermentation strategies by including a prehydrolysis step prior to the SSF and compared the ethanol yields with co-culture fermentation using hexose-fermenting Saccharomyces cerevisiae and pentose-fermenting Scheffersomyces stipitis. Methods: Fed-batch hybrid-SSF and Fed-Batch Separate Hydrolysis and Co-culture Fermentation (F-SHCF) in improving ethanol yield from Steam (ST) or Dilute Sulfuric Acid (DSA) pretreated LCSBs (peels of root and vegetable crops) were studied. Results: There was a progressive build-up of ethanol during F-HSSF up to 72h and further production up to 120h was negligible, with no difference among pretreatments. Despite very high ethanol production in the initial 24h of fermentation by S.cerevisiae under F-SHCF, the further increase was negligible. A rapid hike in ethanol production was observed when S. stipitis was also supplemented because of xylose conversion to ethanol. Conclusion: While ST gave higher ethanol (296-323 ml/kg) than DSA under F-HSSF, the latter was advantageous under F-SHCF for certain residues. Prehydrolysis (24h; 50°C) enhanced initial sugar levels favouring fast fermentation and subsequent saccharification and fermentation occurred concurrently at 37°C for 120h, thus leading to energy saving and hence F-HSSF was advantageous. Owing to the low hemicellulose content in LCSBs, the relative advantage of co-culture fermentation over monoculture fermentation was not significant.

Efficient ethanol production from beetle-killed lodgepole pine using SPORL technology and Saccharomyces cerevisiae without detoxification

TAPPI Journal ◽  
2011 ◽  
Vol 10 (5) ◽  
pp. 9-18 ◽  
Author(s):  
J.Y. ZHU ◽  
XIAOLIN LUO ◽  
SHEN TIAN ◽  
ROLLAND GLEISNER ◽  
JOSÉ NEGRÓN ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Cellulosic Ethanol ◽  
Mountain Pine Beetle ◽  
Ethanol Yield ◽  
Lodgepole Pine ◽  
Energy Output ◽  
Pine Beetle ◽  
Ethanol Yields ◽  
Live Tree

This study applied Sulfite Pretreatment to Overcome Recalcitrance of Lignocelluloses (SPORL) to evaluate the potential of mountain pine beetle-killed lodgepole pine for ethanol production using conventional Saccharomyces cerevisiae without hydrolysate detoxification. The results indicate that the beetle-killed trees are more susceptible to SPORL pretreatment than live trees in addition to having enriched glucan and mannan content as reported in the literature. Ethanol yields of 200 and 250 L/metric ton wood were achieved from a live tree and a dead tree (four years after infestation) without process optimization. Ethanol yield of 220 L/metric ton of wood was obtained from a downed tree with more advanced decomposition, which is approximately 10% more than that from a corresponding live tree. Process mass and energy balance analyses suggest that net ethanol energy output (before distillation, lignin energy excluded) from the decomposing tree was approximately 3.2 GJ/metric ton wood, which is 23% more than that from a corresponding live tree. The study demonstrated the robustness of the SPORL process and the utility of beetle-killed trees for cellulosic ethanol production even after many years post mortality.

scholarly journals Hemicellulosic Bioethanol Production from Fast-Growing Paulownia Biomass

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 173
Author(s):  
Elena Domínguez ◽  
Pablo G. del Río ◽  
Aloia Romaní ◽  
Gil Garrote ◽  
Lucília Domingues
Keyword(s):  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Xylose Reductase ◽  
Energy Crop ◽  
Scheffersomyces Stipitis ◽  
Fractionation Process ◽  
Renewable Source ◽  
Fast Growing ◽  
Engineered Strain

In order to exploit a fast-growing Paulownia hardwood as an energy crop, a xylose-enriched hydrolysate was obtained in this work to increase the ethanol concentration using the hemicellulosic fraction, besides the already widely studied cellulosic fraction. For that, Paulownia elongata x fortunei was submitted to autohydrolysis treatment (210 °C or S0 of 4.08) for the xylan solubilization, mainly as xylooligosaccharides. Afterwards, sequential stages of acid hydrolysis, concentration, and detoxification were evaluated to obtain fermentable sugars. Thus, detoxified and non-detoxified hydrolysates (diluted or not) were fermented for ethanol production using a natural xylose-consuming yeast, Scheffersomyces stipitis CECT 1922, and an industrial Saccharomyces cerevisiae MEC1133 strain, metabolic engineered strain with the xylose reductase/xylitol dehydrogenase pathway. Results from fermentation assays showed that the engineered S. cerevisiae strain produced up to 14.2 g/L of ethanol (corresponding to 0.33 g/g of ethanol yield) using the non-detoxified hydrolysate. Nevertheless, the yeast S. stipitis reached similar values of ethanol, but only in the detoxified hydrolysate. Hence, the fermentation data prove the suitability and robustness of the engineered strain to ferment non-detoxified liquor, and the appropriateness of detoxification of liquor for the use of less robust yeast. In addition, the success of hemicellulose-to-ethanol production obtained in this work shows the Paulownia biomass as a suitable renewable source for ethanol production following a suitable fractionation process within a biorefinery approach.

scholarly journals Effects of Ultrasound on Fermentation of Glucose to Ethanol by Saccharomyces cerevisiae

Fermentation ◽  
2019 ◽  
Vol 5 (1) ◽  
pp. 16 ◽  
Author(s):  
Luis Huezo ◽  
Ajay Shah ◽  
Frederick Michel
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Mass Transfer ◽  
Glucose Uptake ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Biofuel Production ◽  
Inhibitory Effects ◽  
Negative Effects ◽  
Intraparticle Mass Transfer ◽  
Improve Mass Transfer

Previous studies have shown that pretreatment of corn slurries using ultrasound improves starch release and ethanol yield during biofuel production. However, studies on its effects on the mass transfer of substrates and products during fermentation have shown that it can have both beneficial and inhibitory effects. In this study, the effects of ultrasound on mass transfer limitations during fermentation were examined. Calculation of the external and intraparticle observable moduli under a range of conditions indicate that no external or intraparticle mass transfer limitations should exist for the mass transfer of glucose, ethanol, or carbon dioxide. Fermentations of glucose to ethanol using Saccharomyces cerevisiae were conducted at different ultrasound intensities to examine its effects on glucose uptake, ethanol production, and yeast population and viability. Four treatments were compared: direct ultrasound at intensities of 23 and 32 W/L, indirect ultrasound (1.4 W/L), and no-ultrasound. Direct and indirect ultrasound had negative effects on yeast performance and viability, and reduced the rates of glucose uptake and ethanol production. These results indicate that ultrasound during fermentation, at the levels applied, is inhibitory and not expected to improve mass transfer limitations.

scholarly journals POTENCIAL DE CLONES EXPERIMENTAIS DE BATATA-DOCE PARA PRODUÇÃO DE ETANOL

Nativa ◽  
2018 ◽  
Vol 6 (4) ◽  
pp. 352
Author(s):  
Adriano Mendes Lourenço ◽  
Aline Torquato Tavares ◽  
Tiago Alves Ferreira ◽  
Danilo Alves da Silva Porto Lopes ◽  
João Victor Gonçalves Carline ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Sweet Potato ◽  
Ipomoea Batatas ◽  
Ethanol Yield ◽  
Starch Content ◽  
Great Ability ◽  
Ethanol Yields ◽  
Root Starch ◽  
Breeding Selection ◽  
Starch Yield

A batata-doce (Ipomoea batatas (L.) Lam.) tem sido reportada como uma das espécies de planta com grande capacidade de converter biomassa em matéria prima para produção de etanol. O objetivo do trabalho foi avaliar o potencial de clones de batata-doce para produção de etanol. Foram avaliados 60 clones de batata-doce para produtividade de raízes, teor de amido nas raízes, produtividade de amido, coloração da casca e da polpa e o rendimento de etanol. O clone BDTO#122,32 e as cultivares Ana Clara e Carolina Vitória com média de 46,77; 42,75 e 41,25 t ha-¹, respectivamente, foram os que mais conseguiram acumular biomassa na forma de raiz. Os clones que apresentam as maiores médias de produtividade de amido por hectare foram BDTO#144.22 e BDTO#100.23, com valores de 15,46 e 14,16% t ha-1, com rendimentos de etanol de 8,33 e 7,63 m³ ha-¹. Os clones BDTO#144.22 e BDTO#100.23 apresentaram as maiores médias de produtividade de amido por hectare e rendimento de etanol, sendo, portanto, os mais promissores para a produção de etanol.Palavras-chave: Ipomoea batatas (L.) Lam, melhoramento genético, seleção, biocombustível. POTENTIAL OF EXPERIMENTAL CLONES OF SWEET POTATO FOR ETHANOL PRODUCTION ABSTRACT:Sweet potato (Ipomoea batatas (L.) Lam.) Has been reported as one of the plant species with great ability to convert biomass into feedstock for ethanol production. The objective of this work was to evaluate the potential of sweet potato clones for ethanol production. Twenty-six sweet potato clones were evaluated for root productivity, root starch content, starch yield, bark and pulp color, and ethanol yield. Clone BDTO # 122.32 and cultivars Ana Clara and Carolina Vitória averaging 46.77; 42.75 and 41.25 t ha-1, respectively, were the ones that were able to accumulate biomass in the root form. The clones presenting the highest starch productivity per hectare were BDTO # 144.22 and BDTO # 100.23, with values of 15.46 and 14.16% t ha-1, with ethanol yields of 8.33 and 7.63 m³ ha-¹. The clones BDTO # 144.22 and BDTO # 100.23 showed the highest averages of starch productivity per hectare and yield of ethanol, thus being the most promising for the production of ethanol.Keywords: Ipomoea potatoes (L.) Lam, breeding, selection, biofuel.

scholarly journals Ethanol Production from Nondetoxified Dilute-Acid Lignocellulosic Hydrolysate by Cocultures of Saccharomyces cerevisiae Y5 and Pichia stipitis CBS6054

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Ping Wan ◽  
Dongmei Zhai ◽  
Zhen Wang ◽  
Xiushan Yang ◽  
Shen Tian
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Ethanol Concentration ◽  
Ethanol Yield ◽  
Synthetic Medium ◽  
Pichia Stipitis ◽  
Dilute Acid ◽  
Acid Hydrolysate ◽  
Issatchenkia Orientalis ◽  
Final Ethanol Concentration

Saccharomyces cerevisiae Y5 (CGMCC no. 2660) and Issatchenkia orientalis Y4 (CGMCC no. 2159) were combined individually with Pichia stipitis CBS6054 to establish the cocultures of Y5 + CBS6054 and Y4 + CBS6054. The coculture Y5 + CBS6054 effectively metabolized furfural and HMF and converted xylose and glucose mixture to ethanol with ethanol concentration of 16.6 g/L and ethanol yield of 0.46 g ethanol/g sugar, corresponding to 91.2% of the maximal theoretical value in synthetic medium. Accordingly, the nondetoxified dilute-acid hydrolysate was used to produce ethanol by co-culture Y5 + CBS6054. The co-culture consumed glucose along with furfural and HMF completely in 12 h, and all xylose within 96 h, resulting in a final ethanol concentration of 27.4 g/L and ethanol yield of 0.43 g ethanol/g sugar, corresponding to 85.1% of the maximal theoretical value. The results indicated that the co-culture of Y5 + CBS6054 was a satisfying combination for ethanol production from non-detoxified dilute-acid lignocellulosic hydrolysates. This co-culture showed a promising prospect for industrial application.

scholarly journals ATPase-based implementation of enforced ATP wasting in Saccharomyces cerevisiae for improved ethanol production

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Ahmed Zahoor ◽  
Katrin Messerschmidt ◽  
Simon Boecker ◽  
Steffen Klamt
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Atpase Activity ◽  
Ethanol Production ◽  
Ethanol Yield ◽  
Volumetric Productivity ◽  
Anaerobic Growth ◽  
Control Strain ◽  
Genomic Integration ◽  
Expression Of Genes ◽  
Atp Generation

Abstract Background Enforced ATP wasting has been recognized as a promising metabolic engineering strategy to enhance the microbial production of metabolites that are coupled to ATP generation. It also appears to be a suitable approach to improve production of ethanol by Saccharomyces cerevisiae. In the present study, we constructed different S. cerevisiae strains with heterologous expression of genes of the ATP-hydrolyzing F1-part of the ATPase enzyme to induce enforced ATP wasting and quantify the resulting effect on biomass and ethanol formation. Results In contrast to genomic integration, we found that episomal expression of the αβγ subunits of the F1-ATPase genes of Escherichia coli in S. cerevisiae resulted in significantly increased ATPase activity, while neither genomic integration nor episomal expression of the β subunit from Trichoderma reesei could enhance ATPase activity. When grown in minimal medium under anaerobic growth-coupled conditions, the strains expressing E. coli’s F1-ATPase genes showed significantly improved ethanol yield (increase of 10% compared to the control strain). However, elevated product formation reduces biomass formation and, therefore, volumetric productivity. We demonstrate that this negative effect can be overcome under growth-decoupled (nitrogen-starved) operation with high and constant biomass concentration. Under these conditions, which mimic the second (production) phase of a two-stage fermentation process, the ATPase-expressing strains showed significant improvement in volumetric productivity (up to 111%) compared to the control strain. Conclusions Our study shows that expression of genes of the F1-portion of E. coli’s ATPase induces ATPase activity in S. cerevisiae and can be a promising way to improve ethanol production. This ATP-wasting strategy can be easily applied to other metabolites of interest, whose formation is coupled to ATP generation.

Ethanol Production from Different Substrates by a Flocculent Saccharomyces cerevisiae Strain

2009 ◽  
Vol 7 (1) ◽  
Author(s):  
José Duarte ◽  
Vera Lourenço ◽  
Belina Ribeiro ◽  
Maria Céu Saagua ◽  
Joana Pereira ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Yeast Strain ◽  
Fossil Fuels ◽  
Ethanol Yield ◽  
Corn Fiber ◽  
Production Costs ◽  
Raw Material ◽  
Continuous Reactor ◽  
Different Strains

During the last years there has been an increasing interest in using ethanol as a substitute for fossil fuels. The bioethanol used today is mainly produced from sugar cane and cereals, but reducing the production costs of ethanol is still crucial for a viable economic process. Cellulose from vegetable biomass will be the next cheap raw material for second generation fuel ethanol production and agricultural by-products with a low commercial value, as corn stover, corn fiber and cane bagasses would become an attractive feedstock for bioethanol production.In this study, different strains of Saccharomyces cerevisiae have been screened for the ability of bioethanol production. Yeasts were grown in a synthetic liquid medium containing sucrose in batch regime and the growth rates, ethanol and biomass productions were determined as well as their growth ability in cane molasses.The results indicate that a flocculent yeast, isolated in our lab and designated by strain F, was the most promising yeast strain among those tested for continuous ethanol production. This strain was isolated from corn hydrolysates, obtained from a Portuguese distillery facility (DVT, Torres Novas, Portugal) showing highest growth rate (0.49h-1), highest ethanol yield (0.35g/g) and high flocculation capacity.The study on ethanol production in continuous reactor process with the selected yeast strain (strain F) was made on sucrose and cane molasses at different dilution rates (0.05-0.42 h-1). A steady flocculating yeast fluidized bed reactor system was established allowing the functioning of the reactor for 1000 h. Data shows that when the dilution rate rose to 0.42h-1, the highest productivity (20g/Lh) was obtained attaining an ethanol concentration in the reactor of 47g/L for sucrose and molasses media.

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