黄曲霉发酵薯干粉水解液生产L－苹果酸

经选育和诱变得到一株产苹果酸的黄曲霉菌ＴＨ５００７，通过发酵条件的优化，以薯干粉的水解液为主要原料，发酵５ｄＬ－苹果酸可达到６％左右。在总酸中苹果酸含量平均达７２％以上，杂有机酸主要是柠檬酸，延胡索酸的含量在０．０２％以下。补糖发酵比分批发酵产酸性能更佳。

USlNG SWEET POTATO POWDER HYDROLYSATE FOR DIRECT FERMENTATION OF L-MALIC ACID BY ASPERCILLUS FLAVUS

A strain of Aspergillus flauut TH5007 producing L-malic acid was isolatedand selected after a series of subsequent mutation. Various fermentation conditions werestudied to obtain process optimization, characterized by the direct fermentation with thehydrolysate from sweet potato powder. The concentration of L-malic acid in the fermentedbroth can reached to about 6.0%. Among the total acids in the ferinentation broth, Thecontent of malic acid amounts to above 72%. Citric aicd predominanted in the other organicacids than malic acid. The content of fumaric acid can be controlled below 0.02%. Produ-ction of L-malic acid with the fed-batch process is better than that with the batch process.