Effect of salts on the Co-fermentation of glucose and xylose by a genetically engineered strain of Saccharomyces cerevisiae

Casey, Elizabeth; Mosier, Nathan S.; Adamec, Jiřı́; Stockdale, Zachary; Ho, Nancy W. Y.; Sedlák, Miloš

doi:10.1186/1754-6834-6-83

Cited by 68 publications

(54 citation statements)

References 37 publications

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“…All conditions were tested in triplicate. Detailed fermentation methods concerning the cell mass measurement and rate calculations can be found in earlier studies . The ethanol yield in this manuscript is defined as the ethanol concentration at each time interval divided by the maximum theoretical ethanol concentration (0.51 × initial glucose concentration).…”

Section: Methodsmentioning

confidence: 99%

Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation

Aghazadeh

Ladisch

Engelberth

2016

Biotechnology Progress

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Acetic acid is introduced into cellulose conversion processes as a consequence of composition of lignocellulose feedstocks, causing significant inhibition of adapted, genetically modified and wild-type S. cerevisiae in bioethanol fermentation. While adaptation or modification of yeast may reduce inhibition, the most effective approach is to remove the acetic acid prior to fermentation. This work addresses liquid-liquid extraction of acetic acid from biomass hydrolysate through a pathway that mitigates acetic acid inhibition while avoiding the negative effects of the extractant, which itself may exhibit inhibition. Candidate solvents were selected using simulation results from Aspen Plus™, based on their ability to extract acetic acid which was confirmed by experimentation. All solvents showed varying degrees of toxicity toward yeast, but the relative volatility of ethyl acetate enabled its use as simple vacuum evaporation could reduce small concentrations of aqueous ethyl acetate to minimally inhibitory levels. The toxicity threshold of ethyl acetate, in the presence of acetic acid, was found to be 10 g L(-1) . The fermentation was enhanced by extracting 90% of the acetic acid using ethyl acetate, followed by vacuum evaporation to remove 88% removal of residual ethyl acetate along with 10% of the broth. NRRL Y-1546 yeast was used to demonstrate a 13% increase in concentration, 14% in ethanol specific production rate, and 11% ethanol yield. This study demonstrated that extraction of acetic acid with ethyl acetate followed by evaporative removal of ethyl acetate from the raffinate phase has potential to significantly enhance ethanol fermentation in a corn stover bioethanol facility. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:929-937, 2016.

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Section: Methodsmentioning

confidence: 99%

Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation

Aghazadeh

Ladisch

Engelberth

2016

Biotechnology Progress

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“…With the development of exometabolomics pipelines, the metabolic connections between microbes have begun to be studied at a large scale and have allowed for a more comprehensive approach to monitoring the dynamic transformations of relatively complex mixtures of substrates [5]. Some key examples include optimizing multiple steps of lignocellulose degradation [6, 7], understanding metabolic interactions between species in mixed communities [8], and determining the ecological role of individuals within a mixed community [9–11]. We have recently found exometabolite niche partitioning in two soil environments where sympatric microbes were found to target largely non-overlapping portions of the available substrates, thus minimizing substrate competition [10].…”

Section: Introductionmentioning

confidence: 99%

Dynamic substrate preferences predict metabolic properties of a simple microbial consortium

et al. 2017

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BackgroundMixed cultures of different microbial species are increasingly being used to carry out a specific biochemical function in lieu of engineering a single microbe to do the same task. However, knowing how different species’ metabolisms will integrate to reach a desired outcome is a difficult problem that has been studied in great detail using steady-state models. However, many biotechnological processes, as well as natural habitats, represent a more dynamic system. Examining how individual species use resources in their growth medium or environment (exometabolomics) over time in batch culture conditions can provide rich phenotypic data that encompasses regulation and transporters, creating an opportunity to integrate the data into a predictive model of resource use by a mixed community.ResultsHere we use exometabolomic profiling to examine the time-varying substrate depletion from a mixture of 19 amino acids and glucose by two Pseudomonas and one Bacillus species isolated from ground water. Contrary to studies in model organisms, we found surprisingly few correlations between resource preferences and maximal growth rate or biomass composition. We then modeled patterns of substrate depletion, and used these models to examine if substrate usage preferences and substrate depletion kinetics of individual isolates can be used to predict the metabolism of a co-culture of the isolates. We found that most of the substrates fit the model predictions, except for glucose and histidine, which were depleted more slowly than predicted, and proline, glycine, glutamate, lysine and arginine, which were all consumed significantly faster.ConclusionsOur results indicate that a significant portion of a model community’s overall metabolism can be predicted based on the metabolism of the individuals. Based on the nature of our model, the resources that significantly deviate from the prediction highlight potential metabolic pathways affected by species-species interactions, which when further studied can potentially be used to modulate microbial community structure and/or function.Electronic supplementary materialThe online version of this article (doi:10.1186/s12859-017-1478-2) contains supplementary material, which is available to authorized users.

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“…In addition, some metal sulfates have also been used in biorefinery as the metal salts are Lewis acids, which could catalyze the isomerization of sugars, 23,24 retrograde aldol condensation reactions, 25 etc. 26 In aqueous medium, the use of salts could also have the issue of separation from the products. Nevertheless, in organic solvents, the solubilities of some salts are lower and, in the reactive distillation process, the separation of salts from the products might not be necessary.…”

Section: Introductionmentioning

confidence: 99%

Conversion of monosaccharides into levulinic acid/esters: impacts of metal sulfate addition and the reaction medium

Sun

Zhang

Shao

et al. 2019

J of Chemical Tech & Biotech

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BACKGROUND: Inorganic salts could be used as catalysts for the effective conversion of sugars. In this study, the impacts of various metal sulfates (Na 2 SO 4 , K 2 SO 4 , MnSO 4 , CoSO 4 , NiSO 4 , ZnSO 4 , CuSO 4 , Fe 2 (SO 4 ) 3 , La 2 (SO 4 ) 3 and Ce(SO 4 ) 2 ) on the conversion of glucose/fructose to levulinic acid in varied reaction media were evaluated. RESULTS:The sulfates strongly chelated with the sugars, preventing their dehydration reactions in the presence of sulfuric acid and leading to polymerization of the sugars. The sulfates themselves showed varied activity and selectivity for the conversion of the sugars to levulinic acid/esters or 5-hydroxymethylfurfural (HMF), depending on the coordination with the reaction medium. K 2 SO 4 or Na 2 SO 4 could catalyze the production of HMF from glucose/fructose in water, while in DMSO the yield of HMF was substantially higher. In THF, nevertheless, almost no HMF was formed, while other sulfates such as NiSO 4 in THF could effectively catalyze the conversion of fructose to HMF. In alcohols, Fe 2 (SO 4 ) 3 was the most effective sulfate for the conversion of the sugars to levulinic acid/esters, and the alcohols could effectively suppress the polymerization of the sugars. CONCLUSION:The distinct catalytic performances of the sulfates in the varied reaction media originated from their different coordination or chelation with the sugars and the reaction medium.

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Effect of salts on the Co-fermentation of glucose and xylose by a genetically engineered strain of Saccharomyces cerevisiae

Cited by 68 publications

References 37 publications

Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation

Acetic acid removal from corn stover hydrolysate using ethyl acetate and the impact on Saccharomyces cerevisiae bioethanol fermentation

Dynamic substrate preferences predict metabolic properties of a simple microbial consortium

Conversion of monosaccharides into levulinic acid/esters: impacts of metal sulfate addition and the reaction medium

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