关键词: 
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重离子束 /
诱变 /
发酵试验 /
柠檬酸含量

摘要: 应用大剂量重离子束¹²C⁶⁺ 对菌株H3001 进行二次辐照选育，对初选获得的高产柠檬酸菌株进行摇瓶发酵试验及10~ 100 L 中试发酵罐试验，采用酸碱中和法测定发酵液中柠檬酸的含量。结果表明：当二次重离子¹²C⁶⁺剂量为857.8 Gy 时，致死率和正突变率达到最大值，分别为94.5% 和8%。通过摇瓶发酵试验，最终获得一株高产柠檬酸菌株hw317，控制该菌株发酵周期为60 h，柠檬酸酸度能达到19.2±0.2%。Heavy ¹²C⁶⁺ ion beams in various high doses were employed to irradiate H3001 strain for screening Aspergillus niger strain for hyper citric acid production. Three high-yield strains were obtained after shaker fermentation test. Among the three strains, the strain hw317 was implemented shaker fermentation for stability test and 10~100 L pilot fermentation tank for citric acid productive maximization. Acid-base neutralization method was applied to determinate the content of citric acid in fermented liquid. The results showed that: when the secondary heavy ion 12C6+ dose was 857.8 Gy, both of the fatality rate (94.5%) and the positive mutation rate (8%) were highest. Through the shaker fermentation tests and 10 ~ 100 L pilot fermentation test, one strain hw317 was screened and obtained for hyper citric acid production. Consequently, the final citric acid acidity can reach up to 19.2±0.2% with controlling fermentation cycle for 60 h.