一株聚β-羟基丁酸高产菌株的分离与研究 Ⅱ.出发菌株的筛选鉴定及合成PHB条件的研究

Studies on the Selection of a High-yield PHB Producing Strain Ⅱ.Study on the Screening and Identification of Original Strain and the Condition of PHB Synthesis

从城市生活污水中分离筛选到一菌株 ,具如下主要特征 :杆菌 ,(0 .85～ 1 .2 )× (2 .0～ 5.0 )μm;革兰氏染色阴性 ;具衣鞘 ,细胞包在鞘里 ,丝状体很长 ,但无分枝 ;亚端生鞭毛 ;胞内具 PHB颗粒和异染颗粒 ;液化明胶微弱 ;菌落为光滑型和丝状两种 .经鉴定该菌株为浮游球衣细菌(Sphaerotilus natans) .该菌在 2 8℃条件下生长良好 ,细菌细胞大 ,细胞内可积累大量的 PHB.从对数期至稳定期 ,该菌株积累的 PHB量可达细胞干重的 1 9.8%

A strain of sphaerotilus natans from six polluted water samples was isolated. The strain has the following features:bacillus, (0 85～1 2)×(2 0～5 0) μm; Gramnegative bacteria; having sheath with cells in it, very long hypha but without divarication; subterminalflagellum; metachromatic granules and PHB granules in cells; two kinds of colony, the one being smooth, and the other silk. The strain can grow properly under the temperature of 28 ℃ and produce a large amount of PHB granules. The amount of PHB accumulated by the strain could reach as high as 19.8 percent of cell dry weight from log to stable period.