高生物量富硒产朊假丝酵母菌株的选育

从5株优良的发酵酵母菌中筛选出耐硒和富硒能力较好的产朊假丝酵母，采用耐酸驯化和梯度浓度的耐硒驯化增加菌株的抗性。研究表明，产朊假丝酵母Ⅰ的富硒能力更好。在此基础上，经复合诱变、亚硒酸钠抗性平板初筛和摇瓶复筛，筛选出生物量和含硒量都较高的菌株D-5，再将突变株D-5进行紫外诱变，筛选出1株高生物量和高含硒量的菌株U-16，其菌株生物量为5.86 g/L，总硒量为1 575.40 μg/g，有机硒量为1 500.90 μg/g，其有机硒占胞内总硒比重的95.26%。与出发菌株相比，筛选菌株的生物量提高了67.90%，有机硒量增加了95.95%。

Screening of high-biomass and selenium-enriched Candida utilis

Candida utilis, with better selenium-endurance and selenium-enriched ability was screened from 5 excellent yeast strains, after acid acclimation and selenium concentration gradient domestication. Results showed that C. utilis I showed better selenium-enriched ability. On that basis, the strain was treated by compound mutation, sodium selenite resistance plate primarily screening and shake-flask secondary screening, a selenium-enriched strain D-5 with higher biomass was isolated. The strain D-5 was treated with UV mutagenesis, a selenium-enriched and high biomass strain U-16 was selected by using the same method. The biomass of strain U-16 was 5.86 g/L, and the total selenium and organic selenium content was 1 575.40 μg/g and 1 500.90 μg/g, respectively. The organic selenium content accounted for 95.26% of the total selenium in the cell. Compared with the original strain, the biomass and organic selenium was 67.90% higher and 95.95% higher, respectively.