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Indexed by:期刊论文

Date of Publication:2009-01-01

Journal:JOURNAL OF BIOTECHNOLOGY

Included Journals:SCIE、EI、PubMed、Scopus

Volume:139

Issue:1

Page Number:55-60

ISSN No.:0168-1656

Key Words:Continuous ethanol fermentation; Ethanol/thermal tolerance; Self-flocculating yeast; Zinc supplement

Abstract:The effects of zinc supplementation were investigated in the continuous ethanol fermentation using self-flocculating yeast. Zinc sulfate was added at the concentrations of 0.01. 0.05 and 0.1 gl(-1), respectively. Reduced average floc sizes were observed in all the zinc-supplemented Cultures. Both the ethanol tolerance and thermal tolerance were significantly improved by Zinc supplements, which correlated well with the increased ergosterol and trehalose contents in the yeast flocs. The highest ethanol concentration by 0.05 g l(-1) zinc sulfate supplementation attained 114.5 g l(-1), in contrast to 104.1 g l(-1) in the control Culture. Glycerol production was decreased by zinc supplementations, with the lowest level 3.21 g l(-1). about 58% of the control. Zinc content in yeast cells Was about 1.4 mu Mol g(-1) dry cell weight. about sixfold higher than that of control in all the zinc-supplemented red Cultures, and close correlation of zinc content in yeast cells with the cell viability against ethanol and hear shock treatment was observed. These studies suggest that exogenous Zinc addition led to a reprogramming of cellular metabolic network, resulting in enhanced ethanol tolerance and ethanol production. (c) 2008 Elsevier B.V. All rights reserved.