热纤梭菌的分离和鉴定

ISOLATION AND CHRACTERIZATION OF CLOSTRIDIUM THERMOCELLUM

用亨格特(Hungate)厌氧技术,从青贮燕麦草和牛粪中分离出7株热纤梭菌(Clostridiumthermocellum)。它们的编号为 H3、H5、H10、H15、H17、H18和 H19。热纤梭菌在高温下有很强的发酵能力,并转化纤维素为乙醇和有机酸等有价值的产物,具有应用前景。这个种在已报道的高温厌氧分解纤维素梭菌中是比较重要且研究最多的一个种。本文报道该菌株的分离和鉴定。保藏号为 AS1.1783。

Seven strains of thermophilic,obligately anaerobic spore-foming bacteria:H3,H5,H10, H15,H17,H18 and H19 were isolated from the silage oats grass and milk cow feces.The colonies in cellulose agar roll tubes are light yellow,pinpoint,less than 1mm in diameter, sometimes with irregular margins,and fre- quently preduce an yellow pigment.The cells in PY-cellobiose broth are straight or slightly curved rods with tapered ends,occur singly or in pairs,0.3—0.6×1.5—5.5μm,Gram negati- ve,motile and peritrichous,Spores are termi- nal,oval-ellipsoid shaped.Optimum conditions for growth are 50—60℃ and pH 7.5.They mainly ferment cellulose and cellobiose,and produce acetate,ethnol,lactate,hydrogen and carbondioxide.Almost a variety of carbohy- drates can not serve as substrate for growth. Gelatin is not bydrolyzed when cellobiose is included in the medium.Growth factors (?)e- quired are pyridoxine,vitamin B12,p-am(?)no- benzoic acid and biotin.All isolates can (?)ix nitrogen.Exo-glucanase and endo-glucanase were determined.The specific activity of exo- glucanase is more than endo-glucanase. Guanine plus cytosine content of deoxyribonu- cleic acid is 37.8mol%.The seven strains are very similar each other,and thought identical species which was named Clostridium thermocellum.The collection number is AS 1.1783.