Dataset Information

Direct Production of Difructose Anhydride IV from Sucrose by Co-fermentation of Recombinant Yeasts.

ABSTRACT: A functional sweetener, difructose anhydride IV (DFA IV), is enzymatically produced from sucrose via levan by levansucrase (LSRase) followed by levan fructotransferase (LFTase). Here, we have demonstrated a consolidated production system for the direct conversion of DFA IV from sucrose using the co-culture of two recombinant yeast strains secreting LSRase from Bacillus subtilis and LFTase from Arthrobacter ureafaciens, respectively. To ensure secretory production of the enzymes, target protein-specific translational fusion partners (TFP) were employed, and the selected strains produced 3.8?U/mL of LSRase and 16.0?U/mL LFTase activity into the fermentation broth. To optimise the direct production, sucrose concentration and cell ratios were investigated. In the optimised conditions, 64.3?g/L crude DFA IV was directly produced from 244.7?g/L sucrose using co-fermentation of recombinant yeasts. These results promise an efficient production titre, yield, and DFA IV productivity in an industrially applicable method.

SUBMITTER: Ko H

PROVIDER: S-EPMC6828762 | biostudies-literature | 2019 Nov

REPOSITORIES: biostudies-literature

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Direct Production of Difructose Anhydride IV from Sucrose by Co-fermentation of Recombinant Yeasts.

Ko Hyunjun H Bae Jung-Hoon JH Sung Bong Hyun BH Kim Mi-Jin MJ Park Soon-Ho SH Sohn Jung-Hoon JH

Scientific reports 20191104 1

A functional sweetener, difructose anhydride IV (DFA IV), is enzymatically produced from sucrose via levan by levansucrase (LSRase) followed by levan fructotransferase (LFTase). Here, we have demonstrated a consolidated production system for the direct conversion of DFA IV from sucrose using the co-culture of two recombinant yeast strains secreting LSRase from Bacillus subtilis and LFTase from Arthrobacter ureafaciens, respectively. To ensure secretory production of the enzymes, target protein-s ...[more]

PMID: 31685897

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Project description:BackgroundFuture expansion of corn-derived ethanol raises concerns of sustainability and competition with the food industry. Therefore, cellulosic biofuels derived from agricultural waste and dedicated energy crops are necessary. To date, slow and incomplete saccharification as well as high enzyme costs have hindered the economic viability of cellulosic biofuels, and while approaches like simultaneous saccharification and fermentation (SSF) and the use of thermotolerant microorganisms can enhance production, further improvements are needed. Cellulosic emulsions have been shown to enhance saccharification by increasing enzyme contact with cellulose fibers. In this study, we use these emulsions to develop an emulsified SSF (eSSF) process for rapid and efficient cellulosic biofuel production and make a direct three-way comparison of ethanol production between S. cerevisiae, O. polymorpha, and K. marxianus in glucose and cellulosic media at different temperatures.ResultsIn this work, we show that cellulosic emulsions hydrolyze rapidly at temperatures tolerable to yeast, reaching up to 40-fold higher conversion in the first hour compared to microcrystalline cellulose (MCC). To evaluate suitable conditions for the eSSF process, we explored the upper temperature limits for the thermotolerant yeasts Kluyveromyces marxianus and Ogataea polymorpha, as well as Saccharomyces cerevisiae, and observed robust fermentation at up to 46, 50, and 42 °C for each yeast, respectively. We show that the eSSF process reaches high ethanol titers in short processing times, and produces close to theoretical yields at temperatures as low as 30 °C. Finally, we demonstrate the transferability of the eSSF technology to other products by producing the advanced biofuel isobutanol in a light-controlled eSSF using optogenetic regulators, resulting in up to fourfold higher titers relative to MCC SSF.ConclusionsThe eSSF process addresses the main challenges of cellulosic biofuel production by increasing saccharification rate at temperatures tolerable to yeast. The rapid hydrolysis of these emulsions at low temperatures permits fermentation using non-thermotolerant yeasts, short processing times, low enzyme loads, and makes it possible to extend the process to chemicals other than ethanol, such as isobutanol. This transferability establishes the eSSF process as a platform for the sustainable production of biofuels and chemicals as a whole.

Dataset Information

Direct Production of Difructose Anhydride IV from Sucrose by Co-fermentation of Recombinant Yeasts.

Publications

Direct Production of Difructose Anhydride IV from Sucrose by Co-fermentation of Recombinant Yeasts.

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