Enhanced Cobalt Tolerance of Saccharomyces cerevisiae by Engineering the Cytoprotection System

Enhancing cobalt tolerance is crucial for microbial adsorption and recovery of cobalt from wastewater. In this study, metabolic engineering of Saccharomyces cerevisiae was conducted to systematically investigate the effects of modifying cell wall and membrane components and regulating intracellular antioxidant substances glutathione (GSH) and S-adenosylmethionine (SAM) on the improvement of cobalt tolerance. The cobalt tolerance was increased to 157% by overexpression of the erg4 and erg6 genes in the ergosterol metabolic pathways. In the strain where the key cell wall synthesis gene fks2 was knocked out, the cobalt tolerance was increased by 63%. However, this study also found that there was no direct correlation between the intracellular GSH and SAM levels and the cobalt tolerance of the strain. This study provides theoretical support for further improving the tolerance of S. cerevisiae to cobalt ion in the future.