采用平板划线法从纳豆中分离了一株具有γ-聚谷氨酸（γ-polyglutamicacid，γ-PGA）生产能力的菌株（JPND618），通过对该菌株形态、生理生化特性研究以及16S rRNA序列对比分析，对其进行了鉴定。同时对发酵产物进行了分析鉴定，研究了其吸水性能、阻垢性能、絮凝性能及可生物降解性能。结果表明，该菌株生化特征与芽孢杆菌属相似，且其16S rDNA序列与Bacillus amyloliquefaciens NBRC 15535同源性达98%，确定该菌株为解淀粉芽孢杆菌(Bacillus amyloliquefaciens)。发酵生产γ-PGA产量为4.86 g/L，发酵产物γ-PGA的吸水性、可生物降解性明显优于聚丙烯酰胺（PAM），保水性能与PAM相当，对CaSO4、CaCO3的阻垢率最高可达70%以上，对高岭土悬浮液具有良好的絮凝作用，表明菌株JPND618发酵生产γ-PGA是一种性能优良的环境友好型生物材料，具有良好的应用前景。本研究为γ-PGA的发酵生产提供了一株新的菌种，对γ-PGA的生物合成研究及应用具有积极意义。

A γ-polyglutamicacid (γ-PGA) producing strain (JPND618) was isolated using streaked plate method. The strain was identified through strain morphological, physiological-biochemical characteristics and sequence contrastive analysis of 16S rRNA. The fermenting product was identified, and its water absorption property, scale property, flocculation property and biodegradable property were studied. The results showed that, the physiological-biochemical characteristics of strain JPND618 were similar to bacillus genus, and the homelogy of 16S rDNA sequence with Bacillus amyloliquefaciens NBRC 15535 reached 98%, thus strain JPND618 was identified as Bacillus amyloliquefaciens. The yield of γ-PGA was 4.86 g/L. γ-PGA showed much better water absorption and biodegradable property than Polyacrylamide (PAM), and similar water-retaining property with PAM. The anti scale rates towards CaSO4, CaCO3 reached more than 70%, and flocculation towards Gaolin suspension was good. γ-PGA produced by strain JPND618 was proved as a kind of environmental friendly biological materials with high performance, which has a better application prospect. This study supplies a new strain for producing γ-PGA.

陕西省科技厅自然基金项目（2012JM2005）；2012年地方高校国家级大学生创新创业训练计划项目（201210708030）