高效降解OTA的发酵工业用菌株筛选及鉴定

为筛选一株产L-苹果酸能力强的黑曲霉菌株，通过紫外诱变与高浓度放线菌酮迭代诱变的方法，将野生型菌株诱变为一株产L-苹果酸能力强的黑曲霉菌株，并对其种子或发酵培养基成分进行优化。结果表明，诱变所得一株产L-苹果酸能力强的黑曲霉CGMCC NO. 40550菌株，其摇瓶发酵时种子培养基最适葡萄糖浓度为60 g/L、最适氮源为（NH₄）₂SO₄ 4.95 g/L，黑曲霉菌球形成最优转速220 r/min；发酵培养基最适葡萄糖和最适（NH₄）₂SO₄浓度分别为180 g/L和4.95 g/L，CuSO₄·5H₂O为其生产苹果酸最佳微量元素，最适添加量为 0.065 g/L。通过单因素实验的优化，优化后的培养基更有利于L-苹果酸的合成，发酵96 h时L-苹果酸产酸量达到18.15 g/L，显著提高了245%，L-苹果酸占总酸的百分比达到71.69%。本研究为L-苹果酸的工业化生产奠定基础。

Recent advances in microbial production of L-malic acid

In order to screen a strain of Aspergillus niger with high L-malic acid production ability, a wild-type strain was mutagenized into a strain with high L-malic acid production ability by iterative mutagenesis with UV mutagenesis and high concentration of actinomycinone, and the composition of its seed or fermentation medium was optimised. It showed that the optimal glucose concentration of the seed medium was 60 g/L, the optimal nitrogen source was (NH₄)₂SO₄ with 4.95 g/L, and the optimal rotational speed for the formation of A. niger spheres was 220 r/min. The optimal concentration of glucose and (NH₄)₂SO₄ of the fermentation medium were 180 g/L and 4.95 g/L, respectively. CuSO₄·5H₂O was the best trace element for the production of malic acid, with the optimal addition amount of 0.065 g/L. The optimized medium was more conducive to the synthesis of L-malic acid through the optimization of the one-way experiments. The results presented that the production of L-malic acid at 96 h reached 18.15 g/L , which was significantly improved by 245%, and the percentage of L-malic acid in the total acid reached 71.69%. This study lays the foundation for the industrial production of L-malic acid.