Construction and stress tolerance of trehalase mutant in Saccharomyces cerevisiae

Abstract:

[Objective] Accumulation of trehalose is critical in improving the stress tolerance of Saccharomyces cerevisiae. Two enzymes are capable of hydrolyzing trehalose: a neutral trehalase (NTH1) and an acidic trehalase (ATH1). We constructed trehalase disruption mutants to provide a basis for future commercial application. [Methods] To retain the accumulation of trehalose in yeast cell, we constructed diploid homozygous neutral trehalase mutants (△nth1), acid trehalase mutants (△ath1) and double mutants (Δath1Δnth1) by using gene disruption. We tested mutants’trehalose content and their tolerance to freezing, heat, high-sugar and ethanol concentrations. [Results] These trehalase disruption mutants were further confirmed by PCR amplification and southern blot. All mutant strains accumulated higher levels of cellular treha-lose and grew to a higher cell density than the isogenic parent strain. In addition, the levels of trehalose in these mutants correlated with increased tolerance to freezing, heat, high-sugar and ethanol concentration. [Conclusion] The improved tolerance of trehalase mutants may make them useful in commercial applications, including baking and brewing. protein.

Key words:trehalose; △nth1 mutant; △ath1 mutant; Δath1Δnth1 mutant; stress resistance