N^+注入诱变选育混合糖发酵L-乳酸高产菌株  

Breeding of High-yield L-Lactic Acid Strains for Co-fermentation of Glucose and Xylose by N^+ Implantation

作　　者：庞锐[1] 潘丽军[1] 姜绍通[1] 吴学凤[1] 

机构地区：[1]合肥工业大学生物与食品工程学院,安徽合肥230009

出　　处：《食品科学》2010年第21期248-253,共6页Food Science

基　　金：国家"863"计划项目(2007AA10Z361);安徽省自然科学基金项目(090411015)

摘　　要：采用低能N+注入技术对米根霉As3.819进行诱变选育,以提高该菌株利用混合糖(葡萄糖、木糖)发酵生产L-乳酸的能力。实验结果表明,菌株的存活率曲线呈典型的"马鞍型",在注入剂量为50×2.5×1013ions/cm2时具有较高的正突变率。选育获得突变株N50-7,其L-乳酸产量为79.42g/L,比出发菌株提高了17.75%,且遗传稳定性较好。对突变株N50-7的发酵培养基进行了初筛,在混合糖150g/L(葡萄糖100g/L、木糖50g/L)、(NH4)2SO43.0g/L、KH2PO40.3g/L、MgSO4·7H2O0.3g/L、ZnSO4·7H2O0.4g/L的条件下发酵72h,L-乳酸产量最高达到103.81g/L,较初筛前提高了30.71%。In order to increase the production of L-lactic acid by co-fermentation of glucose and xylose, Rhizopus oryzae As3.819 was mutated by low energy N^＋ implantation. The results showed that the survival rate curve was a typical＂saddle shape＂ with a high positive mutation rate at a dose of 50 × 2.5 × 10^13 ions/cm^2. Under this implantation dose, strain N50-7 was obtained with high yield and stability. L-lactic acid yield by N50-7 was 79.42 g/L, 17.75% higher than the original strain. The optimal composition of fermentation medium for N50-7 were as follows： glucose 100 g/L, xylose 50 g/L, （NH4）2SO4 3 g/L, KH2PO4 0.3 g/L, MgSO4-7H2O 0.3 g/L and ZnSO4·7H2O 0.4 g/L. The final concentration of L-lactic acid was 103.81g/L after 72 h fermentation, which was 30.71% higher than that before breeding.

关 键 词：离子注入 米根霉 诱变育种 混合糖 L-乳酸 

分 类 号：TQ920.1[轻工技术与工程—发酵工程]