柠檬酸产生菌诱变选育及发酵的研究

Study on the Breeding of Citric Acid-Producing Strains and Its Fermentation

以分离到的一株黑曲霉Aspergillus niger W1-1为出发菌株,经紫外线、硫酸二乙酯(DES),^(60)Co-γ射线等诱变因子交替处理,筛选出一株产柠檬酸较高的突变株A. niger W1-2,柠檬酸产率由2.9％提高到12.83％以选出的突变株W1-2为发酵用试验菌种,研究了糖源、糖浓度、氮源、氮浓度、培养基初始pH值、培养温度等因素对其产酸的影响,并确定了其最佳发酵条件;蔗糖浓度14％,NH_4Cl 3g/1,培养基初始pH值4.0,培养温度30℃,在此条件下,发酵7天,产酸达12.8％。

The parent strain of Aspergillus niger W1-1 which obtained from natural source was alternatively mutated by UV-ray. DES and 60Co-γ-ray, and high citric acid-producing mutant W1 - 2 which accumulated 12. 8% of citric acid was isolated. The effect of some important factors on citric acid production was investigated, such as: sugar sources, sugar concentration, nitrogen sources, nitrogen concentration, initial pH value of medium and cultural temperature etc. The fermentative conditions were optimized as follows: sucrose 14%, NH4Cl 3g/l, initial pH 4.0, temperature 30℃.