Screening Of Cd²⁺ Resistant Beneficial Yeast And Characterizing On Their Adsorption Capability

With the rapid development of China's industry,the study of beneficial yeast tolerance and adsorption of Cd²⁺is very popular because heavy mental Cd²⁺pollution poses a great threat to the environment and human safety.With potential high resistance to Cd²⁺9 strains of yeast,which were selected from heavy metal contaminated soil were tested on the tolerance capacity and the heavy metal Cd²⁺adsorption capacity through the established high-throughput adsorption method;based on deep-well rectangular plate,the writer established a high-throughput culture method by analyzing the basic parameters of 48 deep-well rectangular plate,the best culture conditions and the optimum activation strain time;using the established high-throughput culture method,the culture medium of the abnormal Wickham Bacterial QF-1-1 strain was optimized by single-factor test and orthogonal test-the basic medium;writer studied the adsorption characteristics from different pH values,temperature,time,heavy metal Cd²⁺concentration,and bacterial concentration by high-throughput adsorption method.The results showed that:9 strains of yeast had a certain tolerance and adsorption capacity for Cd²⁺;the same species of strains showed similar tolerance and similar adsorption to heavy metal Cd²⁺;there was no corresponding relationship between tolerance and its adsorption.Analyzing the basic parameters of 48 deep-well rectangular plate from high temperature resistance,presence of cross-contamination,prevention of moisture evaporation,feasibility,parallelism,etc,writer found that 48 deep-well rectangular plate not only can be used for yeast culture but also can reach shake flask scales;the best culture conditions:liquid volume 1.2ml,speed 1000r/min;in the same condition,yeast culture in 48 deep-well rectangular plate is better than culture in shake bottle;meanwhile,the best time for activation yeast in 48 deep-well rectangular plate is for first generation10 hours,for second generation 8 hours,for third generation 8 hours.The culture medium of the abnormal Wickham Bacterial QF-1-1 strain was optimized by single-factor test and orthogonal test-the basic medium:the potato culture medium;the best carbon source:glucose;the addition amount:10 g/L;the best nitrogen source:yeast dipping powder and its addition mount is 6 g/L;the best inorganic salt:dipotassium hydrogen phosphate and its addition amount is 0.5g/L.Abnormal Wickham's yeast QF-1-1 reached a maximum adsorption of 3.890mg/g at45°C;it's adsorption rate tended to be stable at 60 mins and the adsorption amount reached 3.430 mg/g;the adsorption amount reached a maximum of 3.441 mg at pH 6.0.Besides,when the concentration of bacteria was 11g/L,the maximum adsorption capacity was 5.336mg/g;when the concentration of heavy metal Cd²⁺was 20mg/L,the maximum adsorption capacity was 3.444mg/g.The results of this study will provide data support for the later development of yeast strains to remedy heavy metal Cd²⁺pollution problems.Meanwhile,the established high-throughput culture method will provide a theoretical basis for shortening the culture time and increasing the density of bacteria,importantly it can also be applied to microbial culture.