Bacterial strain ZJB-09211 capable of amidase production has recently been isolated from soil samples. The strain is able to asymmetrically hydrolyze l-tryptophanamide from d,l-tryptophanamide to produce l-tryptophan in high yield and with excellent stereoselectivity (enantiomeric excess > 99.9 %, and enantiomeric ratio > 200). Strain ZJB-09211 has been identified as Flavobacterium aquatile based on the cell morphology analysis, physiological tests, and the 16S rDNA sequence analysis. Optimization of the fermentation medium led to an about six-fold increase in the amidase activity of strain ZJB-09211, which reached 501.5 U L−1. Substrate specifity and stereoselectivity investigations revealed that amidase of F. aquatile possessed a broad substrate spectrum and high enantioselectivity.
近期从土壤样本中分离出一种能产生酰胺酶的细菌菌株ZJB-09211。该菌株能够不对称水解d,l-色氨酸酰胺中的l-色氨酸酰胺,以高产率和优异的立体选择性(对映体过量>99.9%,对映体比例>200)生产l-色氨酸。根据细胞形态分析、生理测试和16S rDNA序列分析,菌株ZJB-09211被鉴定为水生黄杆菌。发酵培养基的优化使得菌株ZJB-09211的酰胺酶活性提高了约六倍,达到501.5 U L−1。底物特异性和立体选择性研究显示,水生黄杆菌的酰胺酶具有广泛的底物谱和高度的对映选择性。