Trehalose accumulation from corn starch by Saccharomycopsis fibuligera A11 during 2-l fermentation and trehalose purification

Abstract

In this study, corn starch was used as the substrate for cell growth and trehalose accumulation by Saccharomycopsis Wbuligera A11. EVect of diVerent aeration rates, agitation speeds, and concentrations of corn starch on direct conversion of corn starch to trehalose by S. Wbuligera A11 were examined using a Biostat B2 2-l fermentor. We found that the optimal conditions for direct conversion of corn starch to trehalose by this yeast strain were that agitation speed was 200 rpm, aeration rate was 4.0 l/min, concentration of corn starch was 2.0% (w/v), initial pH was 5.5, fermentation temperature was 30°C. Under these conditions, over 22.9 g of trehalose per 100 g of cell dry weight was accumulated in the yeast cells, cell mass was 15.2 g/l of the fermentation medium, 0.12% (w/v) of reducing sugar, and 0.21% (w/v) of total sugar were left in the fermented medium within 48 h of the fermentation. It was found that trehalose in the yeast cells could be eYciently extracted by the hot distilled water (80°C). After isolation and puriWcation, the crystal trehalose was obtained from the extract of the cells.

Transcriptomic analysis reveals Aspergillus oryzae responds to temperature stress by regulating sugar metabolism and lipid metabolism

“…Transcriptome analysis and quantification of intracellular sugar revealed that the amyA, MGAM, and treT involved in trehalose synthesis were upregulated, corresponding to the accumulation of intracellular trehalose under low-temperature stress. Chi et al demonstrate that corn starch can be used as the substrate for cell growth and trehalose accumulation in Saccharomycopsis fibuligera [36]. In our study, exogenous starch enhanced the tolerance of A. oryzae to low-temperature stress, implying that A. oryzae might increase the expression levels of amyA, MGAM, and treT to increase the utilization of the exogenous starch to accumulate trehalose, enhancing the adaptation to low-temperature stress.…”

“…Transcriptome analysis and quantification of intracellular sugar revealed that the amyA , MGAM , and treT involved in trehalose synthesis were upregulated, corresponding to the accumulation of intracellular trehalose under low-temperature stress. Chi et al demonstrate that corn starch can be used as the substrate for cell growth and trehalose accumulation in Saccharomycopsis fibuligera [ 36 ]. In our study, exogenous starch enhanced the tolerance of A .…”

Trehalose accumulation from cassava starch and release by a highly thermosensitive and permeable mutant of Saccharomycopsis fibuligera

“…So far, TCA (0.5 M), ethanol, heat shock treatment and hot water (80°C) have been used for extraction of trehalose from fungal cells [9,10,14,17]. However, none of these methods is economical, and they need a large amount of toxic TCA.…”

“…These yeast strains were maintained in YPD medium containing 2.0% (w/v) glucose, 1.0% (w/v) yeast extract and 2.0% (w/v) polypeptone at 4°C or in YPS medium containing 2.0% soluble starch, 1.0% yeast extract and 2.0% polypeptone at 4°C. The trehalose accumulation medium contained 100.0 ml of the hydrolysate of soybean meal supplemented with 2.0% (w/v) cassava starch [9].…”

“…Saccharomycopsis fibuligera is considered one of the best producers of trehalose, a-amylase, glucoamylase, acid protease, raw starch-digesting glucoamylase and b-glucosidase among ascomycetous yeast species, and yeast is known to synthesizes trehalose by the TPS/TPP pathway [8]. Soluble starch, corn starch and cassava starch can be effectively converted into trehalose by yeast cells, and the trehalose content accumulated by the yeast can reach over 23% (w/w) because of its high amylase activity [5,9,20]. However, the accumulated trehalose in the cells of S. fibuligera must be extracted using 0.5 M trichloroacetic acid (TCA) solution, which is toxic and erosive, or hot water (80°C), which is energy consuming [9,20].…”