【摘要】 为了提高柠檬酸的生产水平,利用紫外线(UV)和亚硝基胍(NTG)对柠檬酸生产菌种黑曲霉进行了复合诱变,通过溴甲酚绿选择性平板初筛和摇瓶复筛,获得了一株遗传性能稳定的高产菌株UN-08,产酸率为15.80%.与出发菌株相比,产酸增幅达到26.40%,糖酸转化率为98.75%,发酵指数为1.32 kg/(m3·h).此外,通过对高产菌株UN-08的发酵条件进行研究,确定了此菌株生产接种的适宜孢子数量为106～108个/mL,发酵温度应控制在34～36℃内,溶氧应采用分段控制,前期(0～40 h)应控制在0.12 m3/(m3.min)左右、后期(40～96 h)应控制在0.15 m3/(m3·min)左右.更多还原

【Abstract】 In order to raise the productivity of citric acid,the breeding of Aspergillus niger for citric acid fermentation by ultraviolet(UV) and NTG compound mutation has been studied in this paper.A niger UN-08 has been obtained through a series of screening,which has genetic stability and the citric acid yield of 15.80 g/100 mL,26.40% higher than that of the original niger,the conversion rate of sugar to acid of 98.75% and the fermentation index of 1.32 kg/(m3·h).In addition,the influence of the main technological parameters on the yield of citric acid for niger UN-08 has been studied,which indicates that the optimal number of spores is 106—108 N/mL,the best temperature of fermentation ranges from 34 ℃ to 36 ℃,and ventilation volume should be kept around 0.12 m3/(m3·min)in the early stage(0—40 h)and around 0.15 m3/(m3.min)in the latter stage(40—96 h).更多还原