关键词: 合成生物学, 发酵, 生物技术, 类泛素, 热激蛋白, 蛋白质平衡, 热稳定性

Abstract:

To improve the thermostability and fermentation performance of Saccharomyces cerevisiae to reduce the energy consumption of the cooling progress in industrial fermentation, the protein homeostasis was regulated through ubiquitin-like protein mediation and heat shock response. In this study, many heat-resistant gene devices were mined out from genes related to protein homeostasis and constructed with the regulatory device FBA1p, and then transformed into Saccharomyces cerevisiae INVSC1. Outstanding heat-resistant devices FBA1p-atg8 and FBA1p-hsp104 were screened through gradually increased temperature incubation. Compared with the control, the OD₆₆₀ of the engineered yeast strains S.c-ATG8 and S.c-HSP104 were both over 50% higher (84 h) and their cell viability were 1.64 to 3.01 times higher (72 h) when cultured at 40℃. The physiological characteristics implied that the thermotolerant strains possessed better cell wall integrity and higher trehalose content. In order to strengthening the regulatory mechanisms of both ubiquitin-proteasome system pathway and heat-shock responses within the network of protein homeostasis, atg8 and hsp104 were assembled to construct bifunctional engineered strain S.c-ATG8-HSP104, which showed better growth ability, stronger cell activity and higher ethanol yield at 40℃. The results revealed that the synergistic effect of ubiquitin-like protein and heat shock protein could enhance yeast thermotolerance and improve strain activity.

Key words: synthetic biology, fermentation, biotechnology, ubiquitin-like protein, heat shock protein, protein homeostasis, thermostability