植酸酶高活性菌株的选育及酶性质的初步研究

STUDIES ON SCREENING OF PHYTASE-PRODUCING STRAIN AND PHYTASE

以本实验室筛选的一株米曲霉为出发菌株，通过紫外线诱变，并经过初筛、复筛等步骤而得到一株植酸酶高产菌株，酶活约提高１５６％，最高酶活达２４０Ｕ／ｍｌ粗酶液，７２ｈ左右达到产酶高峰期．植酸酶的最适温度为５６℃，最适ｐＨ为５．５；Ｆｅ２＋、Ｚｎ２＋、Ａｌ３＋对其酶活有强烈的抑制作用。

おァ  mutant strain Aspergillus oryzae M411 with high yield of phytase was obtained from Aspergillus oryzae M105 which was selected from the soil by UV mutation.The enzyme activity of fermentation broth was 240U/ml with the fermentation time of 72 hours.The activity was about 2.5 times of the original strain.The optimal temperature and optimal pH were 56℃ and 5.5,respectively.The enzyme activity is greatly inhibitedby Fe2+、Zn2+、Al3+,but Mg2+ and EDTA has activition effects on phytase activity at the concentration of 1mmol/L