米根霉乙醇脱氢酶(ADH)突变菌株的诱变选育  

The Screening of Alcohol Dehydrogenase (ADH) Mutant of Rhizopus oryzae

作　　者：郑志[1] 姜绍通[1] 罗水忠[1] 李兴江[1] 马林[1] 

机构地区：[1]合肥工业大学生物与食品工程学院,合肥230009

出　　处：《微生物学通报》2007年第1期24-27,共4页Microbiology China

基　　金：教育部博士点基金项目(No.20040359008);教育部"同步辐射博士生创新中心"研究生创新基金资助(No.20041216S)

摘　　要：米根霉发酵生产L-乳酸过程中,由于丙酮酸在丙酮酸脱羧酶、乙醇脱氢酶(ADH)催化下生成乙醇,使得丙酮酸向乳酸转化的流量减少。采用亚硝基胍(NTG)诱变米根霉AS3．3462孢子液,诱变剂量为0．15 mg/ mL时,致死率为70%～80%。在含丙烯醇的YPD筛选培养基上筛选获得两株ADH活力降低的突变株mut-1和mut-2,检测突变株mut-1和mut-2的最大ADH活力分别为35．67和43．09U/mL,是原始菌株的41．63%和50．29%。发酵72h后,原始菌株的乙醇与乳酸浓度分别为28．9g/L和40．31g/L,而mut-1和mut-2突变株的乙醇产量分别为4．87g/L和6．56g/L,乳酸产量为54．45g/L和44．07g/L。在相同的发酵条件下,米根霉ADH突变株mut-1和mut-2对还原糖的利用速率高于出发菌株,其生物量积累亦高于出发菌株。During L-lactic acid fermentation with Rhizopus oryzae, there existed a branch pathway by which pyruvate was transformed to eth- anol catalyzed by pyruvate decarboxylase （PDC） and alcohol dehydrogenase （ADH）, thus decreasing the flux of pyruvate to lactic acid. In this study, the spores of Rhizopus oryzae AS3. 3462 mutagenized with nitrosoguanidine （ NTG）, the appropriate dosage was 0. 15 mg/mL and the lethal rate was 70% - 80%. Two mutants, named mut-1 and mut-2, with decreased ADH activity were screened out by yeast peptone dextrose （YPD） agar medium containing allyl alcohol These two mutants had decreased ADH activities of 41.63 % and 50. 29% compared with the parent strain. The fermentation behavior after 72h showed that the yields of ethanol produced by mut-1 and mut-2 were 4. 87g/L and 6. 56g/L respectively, while the wild type strain was 28. 9g/L, and the lactate concentrations of mut-1 and muto2 also increased from 40. 31g/L to 54. 45g/L and 44.07 g/L, respectively. It is also found that mut-1 and mut-2 had a high reducing sugar consumption rate and biomass accumulation than its present strain.

关 键 词：米根霉 ADH L-乳酸 乙醇 生物量 

分 类 号：TQ920.1[轻工技术与工程—发酵工程]