文献类型：期刊文献

英文题名：Multidimensional engineering of Saccharomyces cerevisiae for the efficient production of heme by exploring the cytotoxicity and tolerance of heme

作者：Guo, Qidi[1];Li, Jiacun[1];Wang, Ming-Rui[1];Zhao, Ming[1];Zhang, Gege[1];Tang, Shuyan[1];Xiong, Liang-Bin[1];Gao, Bei[1];Wang, Feng-Qing[1];Wei, Dong-Zhi[1]

机构：[1]East China Univ Sci & Technol, Newworld Inst Biotechnol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China

年份：2024

卷号：85

起止页码：46

外文期刊名：METABOLIC ENGINEERING

收录：;EI(收录号：20243016738081);WOS:【SCI-EXPANDED(收录号:WOS:001276427700001)】；

基金：This work is supported by the grant from the National Key Research and Development Program of China (2021YFC2100300) , and 2023 Double World-class Project Key Program "Intelligent Biomanufacturing".

语种：英文

外文关键词：Heme; Saccharomyces cerevisiae; Metabolic engineering; Heme cytotoxicity; Laboratory evolution

摘要：Heme has attracted considerable attention due to its indispensable biological roles and applications in healthcare and artificial foods. The development and utilization of edible microorganisms instead of animals to produce heme is the most promising method to promote the large-scale industrial production and safe application of heme. However, the cytotoxicity of heme severely restricts its efficient synthesis by microorganisms, and the cytotoxic mechanism is not fully understood. In this study, the effect of heme toxicity on Saccharomyces cerevisiae was evaluated by enhancing its synthesis using metabolic engineering. The results showed that the accumulation of heme after the disruption of heme homeostasis caused serious impairments in cell growth and metabolism, as demonstrated by significantly poor growth, mitochondrial damage, cell deformations, and chapped cell surfaces, and these features which were further associated with substantially elevated reactive oxygen species (ROS) levels within the cell (mainly H2O2 and superoxide anion radicals). To improve cellular tolerance to heme, 5 rounds of laboratory evolution were performed, increasing heme production by 7.3-fold and 4.2-fold in terms of the titer (38.9 mg/L) and specific production capacity (1.4 mg/L/OD600), respectively. Based on comparative transcriptomic analyses, 32 genes were identified as candidates that can be modified to enhance heme production by more than 20% in S. cerevisiae. The combined overexpression of 5 genes (SPS22, REEL, PHO84, HEM4 and CLB2) was shown to be an optimal method to enhance heme production. Therefore, a strain with enhanced heme tolerance and ROS quenching ability (R5-M) was developed that could generate 380.5 mg/L heme with a productivity of 4.2 mg/L/h in fed-batch fermentation, with S. cerevisiae strains being the highest producers reported to date. These findings highlight the importance of improving heme tolerance for the microbial production of heme and provide a solution for efficient heme production by engineered yeasts.