Progresses in the production of ethanol from lignocellulosic biomass using Saccharomyces cerevisiae by fermentation engineering

2021 ◽  
Vol 2 (1) ◽  
pp. 117-126
Author(s):  
Richmond Godwin Afful ◽  
Tracy Naa Adoley Addotey ◽  
Samaila Boye Ajeje

Ethanol fermentation is a biological procedure which converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as by-products. Since yeasts perform this conversion in the absence of oxygen, alcoholic fermentation is generally considered to be an anaerobic process. Ethanol fermentation has many uses, including the production of alcoholic beverages, the production of ethanol fuel, and bread making. The increasing demand for biofuels around the globe has also prompted the necessity to seek other means to meet the demands. In this review, the general ideologies, methodologies, general chemistry and biochemistry and conditions of the production of ethanol by fermentation engineering using Saccharomyces cerevisiae are highlighted. The quest to reduce pressure on staple foods has necessitated the attention now given to the use of lignocellulose biomass, despite the complexity of the process. It concludes by suggesting ways to improve yield and commercialization of the use of lignocellulosic biomass for ethanol fermentation.

2003 ◽  
Vol 9 (5) ◽  
pp. 371-378 ◽  
Author(s):  
A. I. Flouros ◽  
A. A. Apostolopoulou ◽  
P. G. Demertzis ◽  
K. Akrida-Demertzi

Tsipouro is a traditional Greek alcoholic beverage, produced by distillation of fermented grape pomace. Some of the by-products of the alcoholic fermentation such as acetaldehyde, ethylacetate and amyl alcohols are mainly responsible for the aroma of alcoholic beverages and their amounts specify the quality of the distillate. Several tsipouro samples were stored for 12 months in three types of containers (PET, PVC and glass bottles) to determine the effect of thepackaging material on changes in aroma of the distillate. Determination of volatile compounds was performed by gas chromatography and identification by mass spectrometry. The results revealed that the major volatile constituents of tsipouro were not significantly affected by the container material. Changes in concentrations could be attributed to the natural evolution of the distillate. However, migration of plasticisers from plastic containers into the distillate has been detected, an issue that requires further investigation.


2013 ◽  
Vol 724-725 ◽  
pp. 1116-1121
Author(s):  
Mei Zhen Gong ◽  
Ru Ming Zhao ◽  
Zhi Jun Li ◽  
Juan Yao ◽  
Da Chun Gong

Effect of by-products from wet-oxidation explosion, such as formic acid, acetic acid, and furfural on the growth and fermentation, glycolysis and energy metabolism, cytomembrane integrality ofSaccharomyces cerevisiaewere studied. The results showed that the maximum tolerated concentra tion ofS. cerevisiaewas 1.8 g/L formic acid , 6.0 g/L acetic acid,2.5g/ furfural, respectively. The inhibition strengths of the typical inhibitors to ethanol fermentation were in the order of formic acid , acetic acid , furfural. When the concentration of these typical inhibitors is 1×IC80, acetic acid has the minimum impact on glycolysis and energy metabolism . When the concentration of these typical inhibitors was 2×IC80, furfural had minimum impact on glycolysis and energy metabolism. However , formic acid can inhibit strongly the glycolysis and energy metabolism ofSaccharomyces cerevisiaewith any concentration . When compared with ethanol, the impact of these typical inhibitors onS. cerevisiae's cytomembrane integrality was not very significant. When the concentration of these typical inhibitors varied from 1×IC80to 3×IC80, the results of the leak of Mg2+was 11%-20% formic acid, 5%-12% acetic acid, 4.5%-8.4% furfural, respectively. However, the result of ethanol that leaded to the leak of Mg2+was 55%.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 512 ◽  
Author(s):  
Shafkat Shamim Rahman ◽  
Md. Mahboob Hossain ◽  
Naiyyum Choudhury

Bioethanol obtained from microbial fermentation can replace conventional fossil fuels to satisfy energy demand. In this respect, a fermenting isolate of Saccharomyces cerevisiae, obtained from date juice, was grown in YEPD medium as a part of a previous published research project. In this study, the isolate was tentatively characterized for alcoholic fermentation in organic kitchen waste medium, prepared from discarded fruit and vegetable peels. Fermentation in shaking condition resulted in the production of 7.3% (v/v) ethanol after 48 h, after which the pH of the medium increased slightly in response. Further research should be conducted to assess the potential of kitchen waste as a raw material in ethanol fermentation.


2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Crystal A. Dozier

Pollen is the reproductive agent of flowering plants; palynology is utilized by archaeologists because sporopollenin, a major component in the exine of pollen grains, is resistant to decay and morphologically distinctive. Wine, beer, and mead have been identified in the archaeological record by palynological assessment due to indicator species or due to a pollen profile similar to that recovered from honey, a common source of sugar in a variety of fermented beverages. While most palynologists have assumed that pollen grains are resistant to alcoholic fermentation, a recent study in food science implies that pollen is a yeast nutrient because pollen-enriched meads produce more alcohol. The experiment presented here explores the potential distortion of the pollen record through fermentation by brewing a traditional, pollen-rich mead with Saccharomyces cerevisiae. In this experiment, the pollen grains did not undergo any discernible morphological changes nor were distorted in the pollen profile. Any nutrition that the yeast garners from the pollen therefore leaves sporopollenin intact. These results support palynological research on residues of alcoholic beverages and confirms that the fermentation process does not distort the pollen profile of the original substance. The paper concludes with the potential and limits of palynological study to assess fermentation within the archaeological record.


2008 ◽  
Vol 59 (4) ◽  
Author(s):  
Neculai Catalin Lungu ◽  
Maria Alexandroaei

The aim of the present work is to offer a practical methodology to realise an Arrhenius type kinetic model for a biotechnological process of alcoholic fermentation based on the Saccharomyces cerevisiae yeast. Using the experimental data we can correlate the medium temperature of fermentation with the time needed for a fermentation process under imposed conditions of economic efficiency.


Fermentation ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 59
Author(s):  
Timothy J. Tse ◽  
Daniel J. Wiens ◽  
Jianheng Shen ◽  
Aaron D. Beattie ◽  
Martin J. T. Reaney

As barley and oat production have recently increased in Canada, it has become prudent to investigate these cereal crops as potential feedstocks for alcoholic fermentation. Ethanol and other coproduct yields can vary substantially among fermented feedstocks, which currently consist primarily of wheat and corn. In this study, the liquified mash of milled grains from 28 barley (hulled and hull-less) and 12 oat cultivars were fermented with Saccharomyces cerevisiae to determine concentrations of fermentation products (ethanol, isopropanol, acetic acid, lactic acid, succinic acid, α-glycerylphosphorylcholine (α-GPC), and glycerol). On average, the fermentation of barley produced significantly higher amounts of ethanol, isopropanol, acetic acid, succinic acid, α-GPC, and glycerol than that of oats. The best performing barley cultivars were able to produce up to 78.48 g/L (CDC Clear) ethanol and 1.81 g/L α-GPC (CDC Cowboy). Furthermore, the presence of milled hulls did not impact ethanol yield amongst barley cultivars. Due to its superior ethanol yield compared to oats, barley is a suitable feedstock for ethanol production. In addition, the accumulation of α-GPC could add considerable value to the fermentation of these cereal crops.


Beverages ◽  
2021 ◽  
Vol 7 (2) ◽  
pp. 27
Author(s):  
Dimitrios Kontogiannatos ◽  
Vicky Troianou ◽  
Maria Dimopoulou ◽  
Polydefkis Hatzopoulos ◽  
Yorgos Kotseridis

Nemea and Mantinia are famous wine regions in Greece known for two indigenous grape varieties, Agiorgitiko and Moschofilero, which produce high quality PDO wines. In the present study, indigenous Saccharomyces cerevisiae yeast strains were isolated and identified from spontaneous alcoholic fermentation of Agiorgitiko and Moschofilero musts in order to evaluate their oenological potential. Random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) recovered the presence of five distinct profiles from a total of 430 yeast isolates. The five obtained strains were evaluated at microvinifications trials and tested for basic oenological and biochemical parameters including sulphur dioxide and ethanol tolerance as well as H2S production in sterile grape must. The selected autochthonous yeast strains named, Soi2 (Agiorgitiko wine) and L2M (Moschofilero wine), were evaluated also in industrial (4000L) fermentations to assess their sensorial and oenological characteristics. The volatile compounds of the produced wines were determined by GC-FID. Our results demonstrated the feasibility of using Soi2 and L2M strains in industrial fermentations for Agiorgitiko and Moschofilero grape musts, respectively.


2007 ◽  
Vol 73 (8) ◽  
pp. 2432-2439 ◽  
Author(s):  
Carole Guillaume ◽  
Pierre Delobel ◽  
Jean-Marie Sablayrolles ◽  
Bruno Blondin

ABSTRACT Fructose utilization by wine yeasts is critically important for the maintenance of a high fermentation rate at the end of alcoholic fermentation. A Saccharomyces cerevisiae wine yeast able to ferment grape must sugars to dryness was found to have a high fructose utilization capacity. We investigated the molecular basis of this enhanced fructose utilization capacity by studying the properties of several hexose transporter (HXT) genes. We found that this wine yeast harbored a mutated HXT3 allele. A functional analysis of this mutated allele was performed by examining expression in an hxt1-7Δ strain. Expression of the mutated allele alone was found to be sufficient for producing an increase in fructose utilization during fermentation similar to that observed in the commercial wine yeast. This work provides the first demonstration that the pattern of fructose utilization during wine fermentation can be altered by expression of a mutated hexose transporter in a wine yeast. We also found that the glycolytic flux could be increased by overexpression of the mutant transporter gene, with no effect on fructose utilization. Our data demonstrate that the Hxt3 hexose transporter plays a key role in determining the glucose/fructose utilization ratio during fermentation.


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