【摘要】 对26株产谷氨酸菌进行了由α-氨基丁酸及α-溴丁酸生产 L-异白氨酸的筛选试验。结果表明,多数菌株均能产生 L-异白氨酸,其中最优良的是北京棒状杆菌 AS1.299。研究了 AS1.299菌由α-溴丁酸生产 L-异白氨酸的培养条件。在适宜条件下(葡萄糖10%,脲素0.3%,溴丁酸2%(体积/体积),玉米浆2.5%,碳酸钙o.5%,接种量5%,28℃摇床培养斗天),L-异白氨酸产量达23.9毫克/毫升,溴丁酸的转化率为74%。培养液经 H~+型732强酸性阳离子交换树脂提取,再以等电点-有机溶剂法重结晶。产品经双向纸层析、红外吸收光谱、元素分析及旋光等项鉴定,证明北京棒状杆菌 AS 1.299由α-溴丁酸发酵生产所得产品确系 L-异白氨酸。更多还原

【Abstract】 Screening of L-isoleucine producing strains from 26 strains producing gluta- mic acid was carried out with media con- taining DL-α-bromobutyric acid (BA) as a precursor of L-isoleucine.Most strains screened are capable of produ- cing L-isoleucine from BA.,and the best one is Corynebacterium pekinense AS 1.299. Influence of various conditions on accumulation of L-isoleucine was inves- tigated.Under suitable conditions,strain AS 1.299 produced 23.9 mg/ml L-iso- leucine,the rate of conversion of BA to L-isoleucine was around 74%. The fermentation product isolated and purified from the culture broth has been identified as L-isoleucine.更多还原