scholarly journals Reducing glucoamylase usage for commercial-scale ethanol production from starch using glucoamylase expressing Saccharomyces cerevisiae

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Xin Wang ◽  
Bei Liao ◽  
Zhijun Li ◽  
Guangxin Liu ◽  
Liuyang Diao ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Ethanol Production ◽  
Nitrogen Source ◽  
Culture Media ◽  
Production Condition ◽  
Cassava Starch ◽  
Inoculum Size ◽  
Acid Protease ◽  
Fermentation Performance ◽  
Commercial Scale

AbstractThe development of yeast that converts raw corn or cassava starch to ethanol without adding the exogenous α-amylase and/or glucoamylase would reduce the overall ethanol production cost. In this study, two copies of codon-optimized Saccharomycopsis fibuligera glucoamylase genes were integrated into the genome of the industrial Saccharomyces cerevisiae strain CCTCC M94055, and the resulting strain CIBTS1522 showed comparable basic growth characters with the parental strain. We systemically evaluated the fermentation performance of the CIBTS1522 strain using the raw corn or cassava starch at small and commercial-scale, and observed that a reduction of at least 40% of the dose of glucoamylase was possible when using the CIBTS1522 yeast under real ethanol production condition. Next, we measured the effect of the nitrogen source, the phosphorous source, metal ions, and industrial microbial enzymes on the strain’s cell wet weight and ethanol content, the nitrogen source and acid protease showed a positive effect on these parameters. Finally, orthogonal tests for some other factors including urea, acid protease, inoculum size, and glucoamylase addition were conducted to further optimize the ethanol production. Taken together, the CIBTS1522 strain was identified as an ideal candidate for the bioethanol industry and a better fermentation performance could be achieved by modifying the industrial culture media and condition.

scholarly journals Biomass production and alcoholic fermentation performance of Saccharomyces cerevisiae as a function of nitrogen source

2012 ◽  
Vol 12 (4) ◽  
pp. 477-485 ◽  
Author(s):  
Ruben Martínez-Moreno ◽  
Pilar Morales ◽  
Ramon Gonzalez ◽  
Albert Mas ◽  
Gemma Beltran
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Nitrogen Source ◽  
Biomass Production ◽  
Alcoholic Fermentation ◽  
Fermentation Performance

scholarly journals Blocking mitophagy does not improve fuel ethanol production in Saccharomyces cerevisiae

2021 ◽  
Author(s):  
Kevy Pontes Eliodório ◽  
Gabriel Caetano de Gois e Cunha ◽  
Brianna A White ◽  
Demisha HM Patel ◽  
Fangyi Zhang ◽  
...  
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Viability ◽  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Synthetic Medium ◽  
Fuel Ethanol ◽  
Specific Gene ◽  
Fermentation Performance ◽  
Cell Recycling

Ethanol fermentation is frequently performed under conditions of low nitrogen. In Saccharomyces cerevisiae, nitrogen limitation induces macroautophagy, including the selective removal of mitochondria, also called mitophagy. Shiroma and co-workers (2014) showed that blocking mitophagy by deletion of the mitophagy specific gene ATG32 increased the fermentation performance during the brewing of Ginjo sake. In this study, we tested if a similar strategy could enhance alcoholic fermentation in the context of fuel ethanol production from sugarcane in Brazilian biorefineries. Conditions that mimic the industrial fermentation process indeed induce Atg32-dependent mitophagy in cells of S. cerevisiae PE-2, a strain frequently used in the industry. However, after blocking mitophagy, no differences in CO2production, final ethanol titres or cell viability were observed after five rounds of ethanol fermentation, cell recycling and acid treatment, as commonly performed in sugarcane biorefineries. To test if S. cerevisiae's strain background influences this outcome, cultivations were carried out in a synthetic medium with strains PE-2, Ethanol Red (industrial) and BY (laboratory), with and without a functional ATG32 gene, under oxic and oxygen restricted conditions. Despite the clear differences in sugar consumption, cell viability and ethanol titres, among the three strains, we could not observe any improvement in fermentation performance related to the blocking of mitophagy. We conclude with caution that results obtained with Ginjo sake yeast is an exception and cannot be extrapolated to other yeast strains and that more research is needed to ascertain the role of autophagic processes during fermentation.

scholarly journals Applicability of Saccharomyces cerevisiae Strains for the Production of Fruit Wines Using Cocoa Honey Complemented with Cocoa Pulp

2021 ◽  
Vol 60 (2) ◽  
Author(s):  
Bárbara Teodora Andrade Koelher ◽  
Soraya Maria Moreira de Souza ◽  
Andréa Miura da Costa ◽  
Elizama Aguiar-Oliveira
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Experimental Approach ◽  
Inoculum Size ◽  
Added Value ◽  
Fruit Pulp ◽  
Fermentation Performance ◽  
Scientific Contribution ◽  
Commercial Strain ◽  
Sweet Wine ◽  
Selection Of

Research background. Cocoa honey (CH) and cocoa pulp (CP) are both fruit pulps highly appreciated but, until now, CH is less processed than CP. In this work, it was investigated the applicability of strains of S. cerevisiae to ferment CH complemented with CP, to obtain fruit wines and improve CH commercialization. Experimental approach. The selection of a strain, previously isolated from cachaçaria distilleries in Brazil, took place based on its fermentation performance. The conditions for fermentation with S. cerevisiae L63 were then studied in relation to: volumetric proportion (φCH) of CH (complemented with CP), sucrose addition (γsuc), temperature (T) and inoculum size (No). The best conditions were applied in order to obtain fermentation profiles. Results and conclusions. S. cerevisiae L63 (No=107–108 cell/mL) is capable to ferment φCH of 90 and 80 % (V/V) for 24 or 48 h with γsuc of 50 and 100 g/L at T=28–30 °C resulting in wines with ethanol contents from 8 to 14 % (V/V). Additionally, the φCH=90 % (V/V) wine resulted in the lowest residual sugar concentration (<35 g/L) than the φCH=80 % (V/V) wine (~79 g/L) which could be classified as a sweet wine. In general, S. cerevisiae L63 resulted in a similar fermentation performance than a commercial strain tested, indicating its potential for fruit pulp fermentation. Novelty and scientific contribution. Therefore, S. cerevisiae L63 is capable to ferment CH complemented with CP to produce fruit wines with good commercial potentials that may also benefit small cocoa producers by presenting a product with greater added value.

scholarly journals Comparative Study on Two Commercial Strains ofSaccharomyces cerevisiaefor Optimum Ethanol Production on Industrial Scale

2010 ◽  
Vol 2010 ◽  
pp. 1-5 ◽  
Author(s):  
K. Mukhtar ◽  
M. Asgher ◽  
S. Afghan ◽  
K. Hussain ◽  
S. Zia-ul-Hussnain
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Yeast Cell ◽  
Ethanol Production ◽  
Yeast Strain ◽  
Fermentation Process ◽  
Cell Concentration ◽  
Inoculum Size ◽  
Summer Season ◽  
Maximum Conversion ◽  
Fermentation Parameters

Two commercial strains of Saccharomyces cerevisiae, Saf-Instant (Baker's yeast) and Ethanol red (Mutant) were compared for ethanol production during hot summer season, using molasses diluted up to 6- Brix containing 4%-5% sugars. The yeasts were then propagated in fermentation vessels to study the effects of yeast cell count and varying concentrations of Urea, DAP, inoculum size and Lactrol (Antibiotic). Continuous circulation of mash was maintained for 24 hours and after this fermenter was allowed to stay for a period of 16 hours to give time for maximum conversion of sugars into ethanol. Saccharomyces cerevisiae strain (Saf-instant) with cell concentration of 400 millions/mL at molasses sugar level of 13%–15% (pH , Temp. ), inoculum size of 25% (v/v), urea concentration, 150 ppm, DAP, 53.4 ppm and Lactrol,150 ppm supported maximum ethanol production (8.8%) with  L ethanol per tone molasses (96.5% yield), and had significantly lower concentrations of byproducts. By selecting higher ethanol yielding yeast strain and optimizing the fermentation parameters both yield and economics of the fermentation process can be improved.

scholarly journals Single-step ethanol production from raw cassava starch using a combination of raw starch hydrolysis and fermentation, scale-up from 5-L laboratory and 200-L pilot plant to 3000-L industrial fermenters

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Morakot Krajang ◽  
Kwanruthai Malairuang ◽  
Jatuporn Sukna ◽  
Krongchan Rattanapradit ◽  
Saethawat Chamsart
Keyword(s):  
Ethanol Production ◽  
Ethanol Concentration ◽  
Consolidated Bioprocessing ◽  
Scale Up ◽  
Cassava Starch ◽  
Single Step ◽  
Starch Hydrolysis ◽  
Yield Coefficient ◽  
Raw Starch ◽  
Raw Starch Hydrolysis

Abstract Background A single-step ethanol production is the combination of raw cassava starch hydrolysis and fermentation. For the development of raw starch consolidated bioprocessing technologies, this research was to investigate the optimum conditions and technical procedures for the production of ethanol from raw cassava starch in a single step. It successfully resulted in high yields and productivities of all the experiments from the laboratory, the pilot, through the industrial scales. Yields of ethanol concentration are comparable with those in the commercial industries that use molasses and hydrolyzed starch as the raw materials. Results Before single-step ethanol production, studies of raw cassava starch hydrolysis by a granular starch hydrolyzing enzyme, StargenTM002, were carefully conducted. It successfully converted 80.19% (w/v) of raw cassava starch to glucose at a concentration of 176.41 g/L with a productivity at 2.45 g/L/h when it was pretreated at 60 °C for 1 h with 0.10% (v/w dry starch basis) of Distillase ASP before hydrolysis. The single-step ethanol production at 34 °C in a 5-L fermenter showed that Saccharomyces cerevisiae (Fali, active dry yeast) produced the maximum ethanol concentration, pmax at 81.86 g/L (10.37% v/v) with a yield coefficient, Yp/s of 0.43 g/g, a productivity or production rate, rp at 1.14 g/L/h and an efficiency, Ef of 75.29%. Scale-up experiments of the single-step ethanol production using this method, from the 5-L fermenter to the 200-L fermenter and further to the 3000-L industrial fermenter were successfully achieved with essentially good results. The values of pmax,Yp/s, rp, and Ef of the 200-L scale were at 80.85 g/L (10.25% v/v), 0.42 g/g, 1.12 g/L/h and 74.40%, respectively, and those of the 3000-L scale were at 70.74 g/L (8.97% v/v), 0.38 g/g, 0.98 g/L/h and 67.56%, respectively. Because of using raw starch, major by-products, i.e., glycerol, lactic acid, and acetic acid of all three scales were very low, in ranges of 0.940–1.140, 0.046–0.052, 0.000–0.059 (% w/v), respectively, where are less than those values in the industries. Conclusion The single-step ethanol production using the combination of raw cassava starch hydrolysis and fermentation of three fermentation scales in this study is practicable and feasible for the scale-up of industrial production of ethanol from raw starch.

Application of low-cost algal nitrogen source feeding in fuel ethanol production using high gravity sweet potato medium

2012 ◽  
Vol 160 (3-4) ◽  
pp. 229-235 ◽  
Author(s):  
Yu Shen ◽  
Jin-Song Guo ◽  
You-Peng Chen ◽  
Hai-Dong Zhang ◽  
Xu-Xu Zheng ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Nitrogen Source ◽  
Sweet Potato ◽  
Low Cost ◽  
Fuel Ethanol ◽  
High Gravity
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