Fig. 1

Cell growth test and fermentation with the parent and mutant strains. a YPD plates were used to test the impacts of thermal stress (37 °C) on the growth of the parent and mutants. b MD, and MD-H₂O₂ plates were used to test the impacts of oxidative stress (1 mM H₂O₂) on the growth of the parent and mutants; The lipase fermentation ability of the parent and mutants were test. Cell growth (c, d), protein concentration (e, f), and lipase activity (g, h) were measured and compared. c, e, g The fermentation condition is 28 °C. The growth levels of the parent and mutants were similar, while the protein concentration and enzyme activity of the fermentation broth in G14 was higher than that of the parent. d, f, h The fermentation condition is 37 °C. The protein expression levels of thermotolerant mutants were kept under thermal stress, while the parent can barely grow and express the heterologous protein. The error bars show the standard error of the mean based on three biological replicates