本文以生产果糖基转移酶的米曲霉SBB201（Aspergillus oryzae SBB201）为出发菌株，通过紫外联合氯化锂诱变获得产酶性能与生长性能各自优良的米曲霉菌株UV-A与UV-B，采用非对称灭活法对这两株菌株的原生质体进行紫外以及热灭活双灭活，然后在PEG作为融合剂的介导下进行原生质体双亲融合，筛选出一株果糖基转移酶生产能力有较大提高的米曲霉新菌株，其酶活力达到了172.95 U/g，比出发菌株提高了64.57%。

Screening with enzyme activity and biomass of cell, two mutants (UV-A and UV-B) were obtained from Aspergillus oryzae sbb201 that have been treated with ultraviolet joint lithium chloride mutagenesis. These two parent protoplasts were inactivated with ultraviolet and thermal method respectively, and then fused by PEG induction. A mutant strain was finally obtained which has showed a higher activity of fructosyl-transferase. The enzyme activity reached 172.95 U/g, increased by 64.57% compared with that of the original strain.