Incubation at 25 °C prevents acid crash and enhances alcohol production in Clostridium carboxidivorans P7

Abstract Hexanol–butanol–ethanol fermentation from syngas by Clostridium carboxidivorans P7 is a promising route for biofuel production. However, bacterial agglomeration in the culture of 37 °C severely hampers the accumulation of biomass and products. To investigate the effect of culture temperature on biomass growth and higher-alcohol production, C. carboxidivorans P7 was cultivated at both constant and two-step temperatures in the range from 25 to 37 °C. Meanwhile, Tween-80 and saponin were screened out from eight surfactants to alleviate agglomeration at 37 °C. The results showed that enhanced higher-alcohol production was contributed mainly by the application of two-step temperature culture rather than the addition of anti-agglomeration surfactants. Furthermore, comparative transcriptome revealed that although 37 °C promoted high expression of genes involved in the Wood–Ljungdahl pathway, genes encoding enzymes catalyzing acyl-condensation reactions associated with higher-alcohol production were highly expressed at 25 °C. This study gained greater insight into temperature-effect mechanism on syngas fermentation by C. carboxidivorans P7.

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Electricity-enhanced anaerobic, non-photosynthetic mixotrophy by Clostridium carboxidivorans with increased carbon efficiency and alcohol production

Energy Conversion and Management ◽

10.1016/j.enconman.2021.115118 ◽

2022 ◽

Vol 252 ◽

pp. 115118

Author(s):

Chi Cheng ◽

Yingzhi Shao ◽

Weiming Li ◽

Jiaxin Liu ◽

Xiangzhi Liu ◽

...

Keyword(s):

Alcohol Production ◽

Carbon Efficiency ◽

Clostridium Carboxidivorans

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Purification and Characterization of Natural Solid-Substrate Degrading and Alcohol Producing Hyperthermostable Alkaline Amylase from Bacillus cereus (sm-sr14)

Current Pharmaceutical Biotechnology ◽

10.2174/1389201021666200130113022 ◽

2020 ◽

Vol 21 (9) ◽

pp. 872-881

Author(s):

Sumit Sahoo ◽

Sudipta Roy ◽

Dipannita Santra ◽

Sayantani Maiti ◽

Sonali Roul ◽

...

Keyword(s):

Bacillus Cereus ◽

Main Property ◽

Solid Substrate ◽

Industrial Applications ◽

Starch Degradation ◽

Significant Similarity ◽

Alcohol Production ◽

Cazy Database ◽

Tim Barrel ◽

Alkaline Amylase

Objective: Amylases enzymes hydrolyze starch molecules to produce diverse products including dextrins, and progressively smaller polymers. These include glucose units linked through α-1- 1, α-1-4, α-1-6, glycosidic bonds. Methods: This enzyme carrying an (α /β) 8 or TIM barrel structure is also produced containing the catalytic site residues. These groups of enzymes possess four conserved regions in their primary sequence. In the Carbohydrate-Degrading Enzyme (CAZy) database, α-amylases are classified into different Glycoside Hydrolase Families (GHF) based on their amino acid sequence. The present objective was to study one such enzyme based on its molecular characterization after purification in our laboratory. Its main property of solid-natural starch degradation was extensively investigated for its pharmaceutical/ industrial applications. Results: Amylase producing bacteria Bacillus cereus sm-sr14 (Accession no. KM251578.1) was purified to homogeneity on a Seralose 6B-150 gel-matrix and gave a single peak during HPLC. MALDITOF mass-spectrometry with bioinformatics studies revealed its significant similarity to α/β hydrolase family. The enzyme showed an efficient application; favourable Km, Vmax and Kcat during the catalysis of different natural solid starch materials. Analysis for hydrolytic product showed that this enzyme can be classified as the exo-amylase asit produced a significant amount of glucose. Conclusion: Besides the purified enzyme, the present organism Bacillus cereus sm-sr14 could degrade natural solid starch materials like potato and rice up to the application level in the pharmaceutical/ industrial field for alcohol production.

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A biometric study of higher alcohol production in Saccharomyces cerevisiae

Canadian Journal of Microbiology ◽

10.1139/m90-012 ◽

1990 ◽

Vol 36 (1) ◽

pp. 61-64 ◽

Cited By ~ 57

Author(s):

Paolo Giudici ◽

Patrizia Romano ◽

Carlo Zambonelli

Keyword(s):

Saccharomyces Cerevisiae ◽

Key Words ◽

Isoamyl Alcohol ◽

Higher Alcohols ◽

Methionine Biosynthesis ◽

Higher Alcohol ◽

Strain Characteristic ◽

Alcohol Production ◽

Flocculation Ability ◽

Individual Strain

A hundred strains of Saccharomyces cerevisiae were examined for the ability to produce higher alcohols. In the strains tested the production of higher alcohols was found to be an individual strain characteristic and, as such, was statistically significant. The characteristics of the strains used (flocculation ability, foaming ability, killer character, and non-H2S production) were found to be uncorrelated to isobutanol and isoamyl alcohol production, whereas the production of high levels of n-propanol was found to be related to inability to produce H2S. This, in turn, suggests a link to methionine biosynthesis. Key words: Saccharomyces cerevisiae, higher alcohols, biometry, H2S production.

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