Improved ethanol production in the presence of cadmium ions by a <i>Saccharomyces cerevisiae</i> transformed with a novel cadmium-resistance gene <i>DvCRP1</i>

<p>The <i>DvCRP1</i> gene obtained from <i>Dunaliella viridis</i> is a cadmium-resistance gene that induces cadmium accumulation in microbial and plant cells. In the present study, <i>Saccharomyces cerevisiae</i> was used as a model system to investigate the effect of <i>DvCRP1</i> on both cadmium detoxification and ethanol production. Inhibitory effects of cadmium (50–300 µmol/L) on growth (29–92%), glucose consumption (23–89%), and ethanol production (17–92%) were observed at 24 h by <i>S. cerevisiae</i>. <i>DvCRP1</i> alleviated the inhibitory effect of cadmium, with increase in the ethanol production. The established mathematical model showed that the initial inoculation concentration, cadmium concentration, and transformation of <i>DvCRP1</i> were the most important factors for cell growth, glucose consumption, and ethanol production. Cadmium detoxification of yeast was also enhanced by increasing the initial concentration of yeast cells. Transforming with <i>DvCRP1</i> further enhanced detoxification, especially at high cadmium concentrations. Transforming with DvCRP1 further enhanced detoxification, especially at high cadmium concentrations (200 µmol/L). The present results evidenced the potential of the insertion of the <i>DvCRP1</i> gene into yeast for use in bio-refineries during fermentation of heavy metals-contaminated substrates. In addition, this is a promising method for phytoremediation of agricultural soils highly contaminated by heavy metals.</p>