产植酸酶菌株的筛选及其产酶条件研究

Screening of phytase producing strain and optimization of fermentation conditions

本研究筛选出1株稳定的产植酸酶菌株,初步鉴定为黑曲霉,命名为Aspergullus niger FZ41。摸索了液体发酵产酶的最佳条件,获得其最适发酵培养基(w/w):可溶性淀粉4%,NH4NO30.08%,KCl0.05%,MgSO.47H2O0.05%,FeSO4.7H2O0.003%,MnSO4.7H2O0.003%,水1L。培养基起始pH值6.0,种龄为36h,接种量为5%,装液量为50/500mL,在30℃、220r·min-1下培养84h,酶活可达219U·mL-1。

A phytase-producing strain was isolated and identified as AsperguUus niger FZA1. Liquid fermentation was investigated and the optimal fermentation medium obtained. A 500 mL flask filled with 50 mL inoculums with an initial pH of 6.0 was used in the inoculation. The relative percents of ingredients of fermentation medium were： starch 4% , NH4 NO3 0.08% , KCl 0.05% , MgSO4·7H20 0.05% , FeSO4·7H2O 0.003% , MnSO4·7H2O 0.003%. The age of the inoculums was 36 h, with initial medium pH 6.0 and an inoculation dose of 5%. Extra-cellular phytase production was 219 U·mL^-1 under fermentation conditions of 30℃ at 220 r.min^-1 for 84 h.