枯草芽孢杆菌中性β—甘露聚糖酶的产生及性质

由土壤中分离出一株产中性β甘露聚糖酶的枯草芽孢杆菌（Ｂａｃｉｌｕｓｓｕｂｔｉｌｉｓ），编号ＢＭ９６０２。该菌在液体培养条件下，产生中性β甘露聚糖酶。多糖能作为碳源，而单糖不能作为碳源；有机氮源优于无机氮源。产酶最适培养基组成：魔芋粉４％，牛肉蛋白胨和酵母膏各１％。产酶最适培养条件：培养基起始ｐＨ８５，３５℃，振荡培养３６ｈ。以槐豆胶为底物，培养滤液中性β甘露聚糖酶活力为９６ＩＵ／ｍＬ。酶在ｐＨ５０～１００和５０℃下稳定；作用最适条件为ｐＨ６０和５０℃；水解魔芋粉和槐豆胶均产生寡聚糖。

PRODUCTION OF NEUTRAL BATA MANNANASE BY BACILLUS SUBTILIS AND ITS PROPERTIES

Neutral beta-mannanase was produced by Bacillus subtilis BM9602 isolated from a soil. For this strain the neutral beta-mannanase was produced only when polysaccharides were used as a carbon source. Organic nitrogen source was superior to inorganic nitrogen source on the enzyme production. The optimum liquid medium consisted of 4% konjak powder, 1% each of beef peptone and yeast extract. The optimum culture conditions were initial pH 8.5, temperature 35 degrees C and cultivation time 36 h. Enzyme activity of culture filtrate to 0.5% galactomannan polysaccharide was 96 IU/mL per minute at pH 6.0 and 50 degrees C for 10 min. The optimum pH and temperature for enzyme action were 6.0 and 50 degrees C respectively. The enzyme was stable below 50 degrees C and pH 5.0-10.0. The enzyme hydrolyzed konjak powder and locust bean gum to form oligosaccharides.