产柠檬酸黑曲霉菌种诱变选育及发酵条件优化

为了选育高产柠檬酸菌种，以前期分离到的一株黑曲霉（A spergillusniger）Y Z-35为出发菌株，经紫外线（U V）与硫酸二乙酯（D ES）复合诱变后，进行了产柠檬酸发酵条件优化试验。结果表明，选育出黑曲霉U V -D E-3是一株优良高产菌株，该菌株的产酸率达到11.54%，比初始菌株（Y Z-35）产酸率提高了69.70%；以红薯为发酵原料，在初始糖含量12%、温度35℃、起始pH 值为6.5，转速160 r/m in、发酵时间72 h的优化条件下，摇瓶发酵平均产酸率达到14.24%。

Mutation breeding of citric acid producing Aspergillus n/get and optimization of fermentation conditions

In orderto breed high yield strains ofcitric acid,using the pre-isolated strain ofA spergillus nigerY Z-35 as starting strain afterultraviolet radiation and diethylsulfate com pound m utation,the experim entsofferm entation conditionsoptim ization forcitric acid production w ere carried out. The results show ed thatA .nigerU V -D E-3 w as strain w ith high citric acid production,the acid production rate reached 11.54% ,w hich w as 69.70%higherthan the initialstrain Y Z-35.U sing sw eetpotato as raw m aterial,underthe optim alcondition ofinitialsugarconcentration 12% ,tem perature 35 ℃,initialpH 6.5,rotated speed 160 r/m in,tim e 72 h,the average acid production rate by shake flask ferm entation w as14.24% .