一株高温酸性淀粉酶产生菌的筛选、鉴定及其酶学性质研究

Isolation and identification of a high-temperature acidic amylase-producing bacteria and study on its enzymatic properties

从云南大理市弥渡县石夹泉热泉的55℃底泥中筛选到1株高温淀粉酶的高产菌,进行显微形态及生理生化特征、16SrRNA基因序列分析,将其初步鉴定为苏云金芽孢杆菌(Bacillus thuringiensis)的一株菌,命名为Bacillus thuringiensis Amy-55。对其生长条件及酶学性质进行了研究,结果表明:该菌株耐高温性较好,菌株在55℃仍能生长,菌株最适生长温度为37℃。所产淀粉酶最适酶活温度为75℃,最适反应pH值为5.0。在25℃以下,能保持良好的稳定性,Zn^(2+)和Mn^(2+)对该酶有一定的抑制作用,Ca^(2+)、K^+、Mg^(2+)、Fe^(2+)、Cu^(2+)均对该酶活力起到促进作用,其中Fe^(2+)的促进效果最为明显。

A strain of high-temperature amylase-producing bacteria was screened from the sediment of Shijiaquan hot spring in Midu county,Dali city,Yunnan province.And its morphology,physiological and biochemical characteristics,16S rRNA gene sequence analysis were carried out.The strain was identified as a strain of Bacillus thuringiensis,and named as Bacillus thuringiensisAmy-55.The growth conditions and enzymatic properties of the strain were studied.The results showed that the strain was resistant to high temperature and could still grow at 55℃.The optimum growth temperature was 37℃.The optimum enzyme activity temperature for amylase production was 75℃,and the optimum reaction pH value was 5.0.The enzyme has good stability under 25℃,and Zn 2+and Mn 2+had certain inhibitory effect on the enzyme.Ca2+,K+,Mg2+,Fe2+,Cu2+all played a role in promoting the activity of the enzyme,of which Fe2+was the most obvious.