中文摘要：

[目的]探讨并验证TiCl3法筛选L-苹果酸高产突变株的可行性。[方法]将34株米根霉诱变株及出发株（CK）分别接种到含葡萄糖的发酵培养基中发酵96 h,发酵液经稀释后加入TiCl3,根据沉淀发生情况,筛选L-苹果酸高产突变株。[结果]当发酵液稀释40倍时,有4株诱变株发酵液产生沉淀,而出发株发酵液未产生沉淀。据此筛选出4株发生显著正突变的诱变株,其L-苹果酸产量约为16～20g/L。其发酵液经HPLC测定分析,表明4株突变株发酵液中L-苹果酸的产量为15.88～18.26 g/L,而出发株L-苹果酸产量为11.76 g/L,突变株L-苹果酸产量增幅达35%～55%。[结论]TiCl3法可有效应用于L-苹果酸高产突变株的筛选。

英文摘要：

[Objective] The study was to explore and verify the feasibility of rapid screening on high-yielding mutant of L-malic acid by TiCl3 method. [ Method] 34 induced strains and original strain （CK） of Rhizopus oryzae were inoculated in the fermentation medium that contained glucose to ferment for 96 h, the TiCl3 was added into the diluted broth and the high-yielding mutants of L-malic acid were screened according to the precipitation condition. [Result] The broth with 4 induced strains produced the precipitation, but there was no precipitation in the broth with the original strain when the broth was diluted for 40 times. And according to this, 4 induced swains that had significantly positive mutation were screened and their yield of L-malic acid was 16 - 20 g/L. The detection analysis of HPLC showed that the yield of L-malic acid in the broth with 4 induced mutants was 15.88 - 18.26 g/L, but that with original strain was 11.76 g/L, the increase amplitude of L-malic acid yield of the mutant was 35 % - 55 %. [ Conclusion] The TiCl3 method could be effectively used to screen high-yielding mutant of L-malic acid.