一株产淀粉酶的嗜热地衣芽孢杆菌的筛选及鉴定

Screening and identification of a thermophilic Bacillus licheniformis strain producing amylase

目前,需要将能在高温、高盐和碱性等极端环境中稳定的淀粉酶利用于农业生产中。从云南腾冲热泉附近的土壤样品中分离得到一株菌株,经验证其为一株能够产淀粉酶的嗜热菌。通过测定该菌的16S rRNA基因序列,进行序列比对和构建系统发育树,结合菌落和菌体形态的观察,确定了该菌的分类学地位,并利用非发酵细菌生化鉴定研究了该菌的生理生化性质。结果表明,该菌株为革兰氏阳性细菌,属于地衣芽孢杆菌,命名为CHJ05;通过不同温度和不同pH条件下的生长实验,确定了该菌生长的最佳温度为45℃,最适pH为9,还能在10%NaCl的高盐环境中稳定生长。该菌所产的淀粉酶在30~40℃和pH6~10能保持较高活性,Zn^(2+)、Ca^(2+)、Mg^(2+)三种金属离子对酶活有促进作用,Mn^(2+)和Fe^(2+)对酶活有抑制作用。因此,CHJ05为一株能在高温、高盐以及碱性条件下稳定生长的菌株,为研究和开发在极端环境中继续产淀粉酶的菌株扩大资源储备。

In industrial and agricultural production,amylase is needed with stable activity under extreme environment such as high temperature,high salt and alkaline.In this paper,a strain was isolated from soil samples near Tengchong hot spring in Yunnan Province and proved to be a thermophilic strain capable of amylase production.The 16S rRNA gene sequence of the bacterium was determined,sequence alignment was conducted and phylogenetic tree was constructed.The taxonomic status of the bacterium was determined by observing the morphology of colonies and bacteria.The physiological and biochemical properties of the bacterium were studied by biochemical identification of non-fermentive bacteria.The results showed that the strain belonged to Bacillus licheniformis,a Gram-positive bacterium named CHJ05.Through the growth experiments under different temperature and pH conditions,it was determined that the optimum temperature of growth of this bacterium was 45℃,the optimal pH was 9,and it could also grow stably in high salt environment.At 30~40℃and pH 6~10,the amylase could maintain high activity.The metal ions Zn^(2+),Ca^(2+)and Mg^(2+)promoted the enzyme activity,while Mn^(2+)and Fe^(2+)inhibited the enzyme activity.Therefore,CHJ05 was a strain that could grow stably under high temperature,high salt and alkaline conditions,and the resource reserve was expanded to find strains that could continue to produce amylase in extreme environment.