Biotechnology Bulletin ›› 2023, Vol. 39 ›› Issue (11): 226-237.doi: 10.13560/j.cnki.biotech.bull.1985.2023-0417

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Construction and Mechanism Analysis of High-temperature Resistant Saccharomyces cerevisiae

SUN Yan-qiu1(), XIE Cai-yun1,2(), TANG Yue-qin1,2   

  1. 1. Environmental Biotechnology Research Center, College of Architecture and Environment, Sichuan University, Chengdu 610065
    2. Sichuan Environmental Protection Key Laboratory of Organic Wastes Valorization, Chengdu 610065
  • Received:2023-04-29 Online:2023-11-26 Published:2023-12-20
  • Contact: XIE Cai-yun E-mail:sonyeonchu@qq.com;xiecy@scu.edu.cn

Abstract:

This work aims to construct Saccharomyces cerevisiae strains with excellent high-temperature tolerance and investigate the high-temperature tolerance mechanisms of the strains. CRISPR/Cas9 technology was used to knock out ASP3 in flocculating industrial S. cerevisiae strain KF-7 and further highly expressed CRZ1(Encoding transcription factor Crz1p with zinc finger structure). And the high-temperature tolerance mechanism of the recombinant strains was revealed through comparative transcriptomic analysis. The results showed that the ASP3-knockout strain KAS11 utilized 98.36 g/L glucose and produced 43.68 g/L ethanol at 44℃. After CRZ1 high expression based on KAS11, strain KASCR7 produced 48.02 g/L ethanol from 105.37 g/L glucose. Compared with KF-7, the ethanol production of the two recombinant strains increased by 4.77% and 15.18%, respectively. Comparative transcriptomic analysis revealed that genes involved in ribosome biogenesis and translation significantly repressed in the recombinant strains under high-temperature stress. In contrast, heat shock protein genes as well as genes involved in biosynthesis of NAD+, NADH, purine, glycerol, and proline were significantly induced. These responses may collectively lead to the enhanced high-temperature tolerance of the recombinant strains. The results may provide excellent strain resources and theoretical basis for the construction of excellent high-temperature tolerant S. cerevisiae strains.

Key words: Saccharomyces cerevisiae, fuel ethanol, stress tolerance, high-temperature fermentation, comparative transcriptome