Study on Improving the Cadmium Removal Ability of Recombinant Pichia kudriavzevii M48 Overexpressed MET14 Gene Based on Medium Optimization

In this study, the culture medium of a recombinant Pichia kudriavzevii M48 overexpressed MET14 gene with high cadmium resistance and cadmium removal rate was optimized. Taking the comprehensive value of cadmium removal rate and biomass as the evaluation index, the medium composition was optimized through single factor test, 2^5-1 fractional factorial design and central composite design, so as to provide a research basis for making the recombinant strain M48 into cadmium removal preparation in the later stage. The results showed that the optimal medium was 23.42 g/L glucose, 27.72 g/L yeast extract and 2.04 g/L of potassium dihydrogen phosphate. Under these conditions, the cadmium removal rate of M48 was 79.63% and the biomass was 9.95 g/L, which were 2.70 and 1.16 times higher than that before optimization, respectively. Therefore, the cadmium removal rate and biomass of recombinant strain M48 were effectively increased by optimizing the medium composition.