USlNG SWEET POTATO POWDER HYDROLYSATE FOR DIRECT FERMENTATION OF L-MALIC ACID BY ASPERCILLUS FLAVUS
黄曲霉发酵薯干粉水解液生产L－苹果酸

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.