一种新型淀粉酶的鉴定及其产酶菌株的筛选

对筛选到的菌株ZX99产生的一种新型淀粉酶（异麦芽低聚糖酶）进行了分析鉴定，ZX99菌株能产生一种胞外淀粉酶，该酶能催化淀粉的降解产生异麦芽低聚糖，对原产酶菌株ZX99多次进行紫外线照射诱变后，获得了优良，稳定的变异菌株RB3．232，其产酶水平为原株的160％，产物薄层层析证明，该酶能催化淀粉的降解，产生异麦芽糖，潘糖，异麦芽三糖和异麦芽四糖等低聚糖，但对普鲁兰基本不起作用，由此证明它是一种不同于新型普鲁兰酶（nepullulanase)和 传统淀粉酶（amylase)的一种新型淀粉酶。

IDENTIFICATION OF A NEW TYPE OF AMYLASE AND MUTAGENESIS OF STRAIN ZX99 SECRETING THE ENZYME FOR PRODUCTION OF ISOMALTOOLIGOSACCHARIDE

This paper reported a new type of amylase (neoamylase) secreted by a Bacillus strain ZX99. The enzyme was a kind of ectoenzyme that could catalyze starch into isomalto-oligosaccharide effectively, but could not act on pullulan as substrate. The strain Bacillus ZX99 was mutated by ultraviolet ray and a mutant strain BS3.232 was screened. The activity of the neoamylase produced from BS3.232 increased by 60% over that from ZX99 under the same conditions. The results of thin-layer chromatography of products from starch and pullulan catalyzed by the enzyme demonstrated that the enzyme was different from neopullulanase and can be used to produce isomaltooligosaccharide from starch, including isomaltose, panose, isomaltotriose, isomaltotetose.