荧光假单胞菌抗噬菌体菌株的选育

本实验从荧光假单胞菌（Ｐｓｅｕｄｏｍｏｎａｓｆｌｕｏｒｅｓｃｅｎｓ）ＡＳ—３菌株的不正常发酵液中分离到一种噬菌体，将其命名为ＰＦＡＳ。ＡＳ—３菌株能利用葡萄糖发酵产生Ｄ－异维生素Ｃ的前体物质２－酮基－Ｄ－葡萄糖酸。电镜观察表明ＰＦＡＳ噬菌体呈蝌蚪形，具有直径为６６ｎｍ的六角形头部及长１１７ｎｍ的尾部。通过紫外线诱变及自然选育两种途径，配合简便有效的初筛方法，经多次分离、纯化、复筛最终在摇并发酵试验中获得６株产量稳定地高于对照敏感菌的抗噬菌体菌株，可望用于生产。

SCREENING OF PHAGE-RESISTANT STRAINS IN PSEUDOMONAS FLUORESCENS

A phage,named PFAS,was separated from the abnormal fementation broth of P.fiuorescens AS-3 strain which produced 2-keto-D-gluconic acid i.e.the precursor of D-isovitaminC.The PFAS phage was tadpole-like with a hexagonal head of 66urn in diameter and a tail of 117nmlong observed by electromicroscope.Four thousand resistant colonies against PFAS were obtained byusing U.V.light as a mutagen and through nature selection.Their resistance was confirmed.After repeated separation,purification and selection,six resistant strains against the PFAS werefinally obtained based on shaking flask fermentation result.They gave a higher yield in2-keto-D-gluconic acid than the original sensitive strain and could be used in industrial fermantationprocess.