scholarly journals The Xylose Metabolizing Yeast Spathaspora passalidarum is a Promising Genetic Treasure for Improving Bioethanol Production

Fermentation ◽  
2020 ◽  
Vol 6 (1) ◽  
pp. 33 ◽  
Author(s):  
Khaled A. Selim ◽  
Saadia M. Easa ◽  
Ahmed I. El-Diwany
Keyword(s):  
Molecular Mechanisms ◽  
Agricultural Waste ◽  
Pichia Stipitis ◽  
Biofuel Production ◽  
Bioethanol Production ◽  
Petroleum Resources ◽  
Pentose Sugar ◽  
Industrial Strains ◽  
Founder Member ◽  
Spathaspora Passalidarum

Currently, the fermentation technology for recycling agriculture waste for generation of alternative renewable biofuels is getting more and more attention because of the environmental merits of biofuels for decreasing the rapid rise of greenhouse gas effects compared to petrochemical, keeping in mind the increase of petrol cost and the exhaustion of limited petroleum resources. One of widely used biofuels is bioethanol, and the use of yeasts for commercial fermentation of cellulosic and hemicellulosic agricultural biomasses is one of the growing biotechnological trends for bioethanol production. Effective fermentation and assimilation of xylose, the major pentose sugar element of plant cell walls and the second most abundant carbohydrate, is a bottleneck step towards a robust biofuel production from agricultural waste materials. Hence, several attempts were implemented to engineer the conventional Saccharomyces cerevisiae yeast to transport and ferment xylose because naturally it does not use xylose, using genetic materials of Pichia stipitis, the pioneer native xylose fermenting yeast. Recently, the nonconventional yeast Spathaspora passalidarum appeared as a founder member of a new small group of yeasts that, like Pichia stipitis, can utilize and ferment xylose. Therefore, the understanding of the molecular mechanisms regulating the xylose assimilation in such pentose fermenting yeasts will enable us to eliminate the obstacles in the biofuels pipeline, and to develop industrial strains by means of genetic engineering to increase the availability of renewable biofuel products from agricultural biomass. In this review, we will highlight the recent advances in the field of native xylose metabolizing yeasts, with special emphasis on S. passalidarum for improving bioethanol production.

scholarly journals Functional Expression of Pichia Stipitis XR and XDH Genes into Starter Cultures of Saccharomyces cerevisiae Obtained from Degrading Cocoa (Theobroma cacao L.) Pod Husk Biomass

2019 ◽  
pp. 1-13
Author(s):  
R. O. Igbinadolor ◽  
C. V. Bruschi ◽  
A. A. Onilude
Keyword(s):  
Theobroma Cacao ◽  
Genomic Dna ◽  
Fossil Fuels ◽  
Agricultural Waste ◽  
Pichia Stipitis ◽  
Starter Cultures ◽  
Biofuel Production ◽  
Complex Nature ◽  
Cocoa Pod Husk ◽  
Theobroma Cacao L

Biobased energy and fuels are among the exercisable sustainable energy options mankind has in the not-so-distant future as issues pertaining to global warming and shortfall in fossil fuels loom dark over the planet. The environmental necessity to stop this development by switching to alternative strategies nowadays is generally undisputed. Biofuel made from biomass provide unique environmental economic strategic benefit and can be considered as safe and by and large, the cleanest liquid fuel alternative to fossil fuels. Biofuel produced from Agricultural waste biomass like cocoa (Theobroma cacao L) pod husk shows many potentials advantages in comparison with sugar or starch-based stocks since the latter materials are also food for human and animals. However, the complex nature of this biomass necessitates the use of genetic techniques to produce engineered organisms that are able to transform this polymer into the desired product. With Bioinformatics tools using NCBI BLAST programme, two genes XL1 and XL2 encoding pentose utilization were isolated from the genomic DNA of Pichia stipitis (CBS 6054) and two primers each were designed to span the full coding region of these genes with attached enzymes restriction sites using DNA strider 1.4f7 and Macplasmap programmes. PCR reactions were carried out on 120hg of the isolated genomic DNA for 30 cycles using the DNA Gotaq polymerase enzyme. The amplified PCR fragments were introduced into plasmid vectors pGAPZA and pVT100-U respectively and the constructs were then used to transform the selected ethanol-producing strain of S. cerevisiae (BY4743) isolated from degrading cocoa pod husk biomass meant to serve as starter for biofuel production from cocoa pod husk hydrolysate.

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.

scholarly journals Diverse Banana Pseudostems and Rachis Are Distinctive for Edible Carbohydrates and Lignocellulose Saccharification towards High Bioethanol Production under Chemical and Liquid Hot Water Pretreatments

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3870
Author(s):  
Jingyang Li ◽  
Fei Liu ◽  
Hua Yu ◽  
Yuqi Li ◽  
Shiguang Zhou ◽  
...  
Keyword(s):  
Soluble Sugars ◽  
Enzymatic Saccharification ◽  
Hot Water ◽  
Biofuel Production ◽  
Bioenergy Crops ◽  
Bioethanol Production ◽  
Factors Affecting ◽  
Liquid Hot Water ◽  
Biomass Processing ◽  
Banana Crops

Banana is a major fruit crop throughout the world with abundant lignocellulose in the pseudostem and rachis residues for biofuel production. In this study, we collected a total of 11 pseudostems and rachis samples that were originally derived from different genetic types and ecological locations of banana crops and then examined largely varied edible carbohydrates (soluble sugars, starch) and lignocellulose compositions. By performing chemical (H2SO4, NaOH) and liquid hot water (LHW) pretreatments, we also found a remarkable variation in biomass enzymatic saccharification and bioethanol production among all banana samples examined. Consequently, this study identified a desirable banana (Refen1, subgroup Pisang Awak) crop containing large amounts of edible carbohydrates and completely digestible lignocellulose, which could be combined to achieve the highest bioethanol yields of 31–38% (% dry matter), compared with previously reported ones in other bioenergy crops. Chemical analysis further indicated that the cellulose CrI and lignin G-monomer should be two major recalcitrant factors affecting biomass enzymatic saccharification in banana pseudostems and rachis. Therefore, this study not only examined rich edible carbohydrates for food in the banana pseudostems but also detected digestible lignocellulose for bioethanol production in rachis tissue, providing a strategy applicable for genetic breeding and biomass processing in banana crops.

Bioethanol Production of Cellulase Producing Bacteria from Soils of Agrowaste Field

2021 ◽  
Vol 13 (2) ◽  
pp. 643-655
Author(s):  
A. Thomas ◽  
M. Laxmi ◽  
A. Benny
Keyword(s):  
Treatment Process ◽  
Agricultural Waste ◽  
Cellulase Production ◽  
Cellulolytic Enzymes ◽  
Bioethanol Production ◽  
Ethanolic Fermentation ◽  
Cellulose Bioconversion ◽  
Congo Red Staining ◽  
Pre Treatment ◽  
And Staphylococcus Aureus

With decades of studies on cellulose bioconversion, cellulases have been playing an important role in producing fermentable sugars from lignocellulosic biomass. Copious microorganisms that are able to degrade cellulose have been isolated and identified. The present study has been undertaken to isolate and screen the cellulase producing bacteria from soils of agrowaste field. Cellulase production has been qualitatively analyzed in carboxy methylcellulose (CMC) agar medium after congo red staining and NaCl treatment by interpretation with zones around the potent colonies. Out of the seven isolates, only two showed cellulase production. The morphogical and molecular characterization revealed its identity as Escherichia coli and Staphylococcus aureus. The potential of organisms for bioethanol production has been investigated using two substrates, namely, paper and leaves by subjecting with a pre-treatment process using acid hydrolysis to remove lignin which acts as physical barrier to cellulolytic enzymes. Ethanolic fermentation was done using Saccharomyces cerevisiae for 24-48 h and then the bioethanol produced was qualitatively proved by iodoform assay. These finding proves that ethanol can be made from the agricultural waste and the process is recommended as a means of generating wealth from waste.

Processes simulation and environmental evaluation of biofuel production via Co-pyrolysis of tropical agricultural waste

Energy ◽  
2021 ◽  
pp. 123016
Author(s):  
Wenyu Mo ◽  
Zhe Xiong ◽  
Huiyi Leong ◽  
Xi Gong ◽  
Long Jiang ◽  
...  
Keyword(s):  
Agricultural Waste ◽  
Biofuel Production ◽  
Environmental Evaluation

scholarly journals Bioethanol Production using a Yeast Pichia stipitis from the Hydrolysate of Ulva pertusa Kjellman

2011 ◽  
Vol 39 (3) ◽  
pp. 243-248 ◽  
Author(s):  
Ji-Eun Lee ◽  
Sang-Eun Lee ◽  
Woon-Yong Choi ◽  
Do-Hyung Kang ◽  
Hyeon-Yong Lee ◽  
...  
Keyword(s):  
Pichia Stipitis ◽  
Ulva Pertusa ◽  
Bioethanol Production

scholarly journals Transcriptomic Changes Induced by Deletion of Transcriptional Regulator GCR2 on Pentose Sugar Metabolism in Saccharomyces cerevisiae

2021 ◽  
Vol 9 ◽  
Author(s):  
Minhye Shin ◽  
Heeyoung Park ◽  
Sooah Kim ◽  
Eun Joong Oh ◽  
Deokyeol Jeong ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Xylose Fermentation ◽  
Sugar Metabolism ◽  
Pentose Phosphate ◽  
Biofuel Production ◽  
Rna Seq ◽  
Loss Of Function ◽  
Lignocellulosic Biofuel ◽  
Pentose Sugar ◽  
Transcriptomic Changes

Being a microbial host for lignocellulosic biofuel production, Saccharomyces cerevisiae needs to be engineered to express a heterologous xylose pathway; however, it has been challenging to optimize the engineered strain for efficient and rapid fermentation of xylose. Deletion of PHO13 (Δpho13) has been reported to be a crucial genetic perturbation in improving xylose fermentation. A confirmed mechanism of the Δpho13 effect on xylose fermentation is that the Δpho13 transcriptionally activates the genes in the non-oxidative pentose phosphate pathway (PPP). In the current study, we found a couple of engineered strains, of which phenotypes were not affected by Δpho13 (Δpho13-negative), among many others we examined. Genome resequencing of the Δpho13-negative strains revealed that a loss-of-function mutation in GCR2 was responsible for the phenotype. Gcr2 is a global transcriptional factor involved in glucose metabolism. The results of RNA-seq confirmed that the deletion of GCR2 (Δgcr2) led to the upregulation of PPP genes as well as downregulation of glycolytic genes, and changes were more significant under xylose conditions than those under glucose conditions. Although there was no synergistic effect between Δpho13 and Δgcr2 in improving xylose fermentation, these results suggested that GCR2 is a novel knockout target in improving lignocellulosic ethanol production.

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