The effect of sulfide and ammonia on cassava fermentation for ethanol production in an ethanol–methane coupled system

2011 ◽  
Vol 64 (10) ◽  
pp. 2066-2071 ◽  
Author(s):  
Ke Wang ◽  
Li Jiang ◽  
ZhongGui Mao ◽  
ChengMing Zhang ◽  
JianHua Zhang ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Coupled System ◽  
Total Sugar ◽  
Fermentation Performance ◽  
Two Stage ◽  
Total Consumption ◽  
Wastewater Pollution ◽  
Final Ethanol Concentration

An ethanol–methane coupled system was proposed to resolve wastewater pollution in cassava ethanol production. The wastewater originated from ethanol distillation is treated with two-stage anaerobic digestion and then recycled for medium preparation for the next batch ethanol fermentation, thus eliminating wastewater discharge and saving fresh water. The constituents of the two-stage anaerobic digestion effluent were complex which influenced the ethanol fermentation performance. This paper aimed to study the effect of two constituents in the effluent, i.e. sulfide and ammonia, on cassava-based ethanol fermentation performance. It was found that sulfide reduced the consumption rate of total sugar by significantly inhibiting the growth of Saccharomyces cerevisiae, but the total consumption amount of total sugar at the end of fermentation was not influenced. S. cerevisiae produced more glycerol and less ethanol at the end of fermentation containing higher concentration of sodium sulfide. Ethanol fermentation performance could be hardly influenced by the sulfide in the two-stage effluent because of the very low concentration. More glycerol was produced while final ethanol concentration was reduced when the level of ammonia in the two-stage effluent was higher.

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.

Suitability of anaerobic digestion effluent as process water for corn fuel ethanol fermentation

2014 ◽  
Vol 69 (9) ◽  
pp. 1894-1899 ◽  
Author(s):  
Ke Wang ◽  
Jian-Hua Zhang ◽  
Pei Liu ◽  
Zhong-Gui Mao
Keyword(s):  
Anaerobic Digestion ◽  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Fuel Ethanol ◽  
Ammonium Nitrogen ◽  
Process Water ◽  
Ammonium Concentration ◽  
Net Energy ◽  
Corn Ethanol ◽  
Thin Stillage

A corn fuel ethanol plant integrated with anaerobic digestion treatment of thin stillage increases the net energy balance. Furthermore, the anaerobic digestion effluent (ADE) can be reused as a potential substitute for process water in the ethanol fermentation. In this study, the suitability of ADE as process water for corn ethanol fermentation was investigated by analyzing the potential inhibitory components in the ADE. It was found that ammonium influenced the growth and metabolism of Saccharomyces cerevisiae. Maximum ethanol production was obtained when the concentration of ammonium nitrogen was 200 mg/L, and ammonium could replace urea as the nitrogen source for S. cerevisiae under this concentration. In the ethanol fermentation with a higher concentration of ammonium, more glycerol was produced, thereby resulting in the decrease of ethanol production. In addition, components except ammonium in the ADE caused no inhibition to ethanol production. These results suggest that ADE could be reused as process water for corn ethanol fermentation without negative effect when ammonium concentration is well controlled.

Effect of Recycled Two-Stage Anaerobic Digestion Effluent on Very High Gravity Cassava-Based Ethanol Fermentation

2011 ◽  
Vol 5 (3) ◽  
pp. 351-356 ◽  
Author(s):  
Ke Wang ◽  
Li Jiang ◽  
Zhong-Gui Mao ◽  
Cheng-Ming Zhang ◽  
Jian-Hua Zhang ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Ethanol Fermentation ◽  
High Gravity ◽  
Two Stage ◽  
Very High Gravity ◽  
Very High

Two-Stage anaerobic digestion in agroindustrial waste treatment: A review

2021 ◽  
Vol 281 ◽  
pp. 111854
Author(s):  
Paulo André Cremonez ◽  
Joel Gustavo Teleken ◽  
Thompson Ricardo Weiser Meier ◽  
Helton José Alves
Keyword(s):  
Anaerobic Digestion ◽  
Waste Treatment ◽  
Two Stage ◽  
Agroindustrial Waste

scholarly journals Novel Antarctic yeast adapts to cold by switching energy metabolism and increasing small RNA synthesis

2021 ◽  
Author(s):  
D. Touchette ◽  
I. Altshuler ◽  
C. Gostinčar ◽  
P. Zalar ◽  
I. Raymond-Bouchard ◽  
...  
Keyword(s):  
Ethanol Production ◽  
Ethanol Fermentation ◽  
Phylogenetic Analyses ◽  
Regulation Of Gene Expression ◽  
Pentose Phosphate ◽  
Metabolic Switch ◽  
Antarctic Yeast ◽  
Fungal Adaptation ◽  
Pentose Phosphate Pathways ◽  
Post Transcriptional Regulation

AbstractThe novel extremophilic yeast Rhodotorula frigidialcoholis, formerly R. JG1b, was isolated from ice-cemented permafrost in University Valley (Antarctic), one of coldest and driest environments on Earth. Phenotypic and phylogenetic analyses classified R. frigidialcoholis as a novel species. To characterize its cold-adaptive strategies, we performed mRNA and sRNA transcriptomic analyses, phenotypic profiling, and assessed ethanol production at 0 and 23 °C. Downregulation of the ETC and citrate cycle genes, overexpression of fermentation and pentose phosphate pathways genes, growth without reduction of tetrazolium dye, and our discovery of ethanol production at 0 °C indicate that R. frigidialcoholis induces a metabolic switch from respiration to ethanol fermentation as adaptation in Antarctic permafrost. This is the first report of microbial ethanol fermentation utilized as the major energy pathway in response to cold and the coldest temperature reported for natural ethanol production. R. frigidialcoholis increased its diversity and abundance of sRNAs when grown at 0 versus 23 °C. This was consistent with increase in transcription of Dicer, a key protein for sRNA processing. Our results strongly imply that post-transcriptional regulation of gene expression and mRNA silencing may be a novel evolutionary fungal adaptation in the cryosphere.

Increasing 2 -Bio- (H2 and CH4) production from food waste by combining two-stage anaerobic digestion and electrodialysis for continuous volatile fatty acids removal

2021 ◽  
Vol 129 ◽  
pp. 20-25
Author(s):  
Gamal K. Hassan ◽  
Rhys Jon Jones ◽  
Jaime Massanet-Nicolau ◽  
Richard Dinsdale ◽  
M.M. Abo-Aly ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Anaerobic Digestion ◽  
Food Waste ◽  
Volatile Fatty Acids ◽  
Two Stage ◽  
Ch4 Production

scholarly journals Integration of a Water Scrubbing Technique and Two-Stage Pressurized Anaerobic Digestion in One Process

Energies ◽  
2015 ◽  
Vol 8 (3) ◽  
pp. 2048-2065 ◽  
Author(s):  
Andreas Lemmer ◽  
Yuling Chen ◽  
Anna-Maria Wonneberger ◽  
Frank Graf ◽  
Rainer Reimert
Keyword(s):  
Anaerobic Digestion ◽  
Two Stage
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