豆豉优势细菌菌株的酶活、抑菌作用和初步鉴定

Enzymatic activity,antimicrobial effect and preliminary identification of predominant bacterial strains from Douchi

为了获得豆豉多菌种发酵的候选菌株,以著名的自然发酵豆豉——黄姚豆豉和天马山豆豉为材料,首先采用平板划线法分离纯化其中的优势细菌菌株,接着采用透明圈法考察这些菌株对蛋白质、淀粉和纤维素的分解能力,然后采用琼脂平板扩散法考察具有分解能力的菌株对大肠杆菌、金黄色葡萄球菌和沙门氏菌的抑制作用,最后根据形态及生理生化特征对菌株进行鉴定。结果表明,黄姚豆豉和天马山豆豉各存在3种不同菌落形态的优势细菌菌株,分别命名为HX-1、HX-2、HX-3和TX-1、TX-2、TX-3;分解蛋白质能力最强的是菌株HX-1,分解淀粉和纤维素能力最强的是菌株TX-1;菌株HX-1和TX-1不仅对蛋白质、淀粉和纤维素都具有分解能力,而且对大肠杆菌具有抑制作用,均为枯草芽孢杆菌。

Samples of Huangyao Douchi and Tianmashan Douchi were used as raw materials for the aim of candidate strains collection for preparation of Douchi with multi-strain fermentation. Predominant bacterial were isolated and purified by plate streaking. Ability to degrade protein, starch and cellulous of these sWains were evaluated by clear zone method. Antimicrobial effect on EscheHchia coli, Staphylococcus aureus and Salmonella sp. was studied with agar disk diffusion method. Strains were identified with morphological, physiological and biochemical characteristics. The results indicated that three predominant bacterial strains with different colonial morphology were found respectively in Huangyao Douchi and Tianmashan Douchi, which were named as HX-1, HX-2, HX-3 and TX-1, TX-2, TX-3. Strains HX-1 and TX-1 had the strongest ability to decompose protein and starch and cellulose, respectively. Strains HX-1 and TX-1 belong to species of Bacillus subtilis and have abilities to decompose protein, starch and cellulose, and inhibit growth ofEscherichia coli, as well.