A soil bacterium with α-L-rhamnosidase was isolated from a cumulative mixed culture containing a polysaccharide of gellan as a carbon source and identified to be Sphingomonas paucimobilis, known as a potent producer of gellan. The isolate (designated Sphingomonas sp. R1) produced an unusual exopolysaccharide of sphingan (denoted HWR1) distinct from gellan. The rhamnose in gellan was replaced with mannose in HWR1. The bacterium had a peculiar cell surface covered with many complicated plaits. α-L-Rhamnosidase purified from Sphingomonas sp. R1 grown in the presence of naringin was a monomer with a molecular mass of 110 kDa and most active at pH 8.0 and 50°C. The enzyme required divalent metal ions for the activity and released L-rhamnose from various rhamnosyl glycosides.
从含有作为碳源的结冷
多糖的混合培养物中分离出一种具有α-
L-鼠李糖苷酶的土壤细菌,并鉴定为Sphingomonas paucimobilis,这是一种结冷的有效生产菌。分离物(命名为Sphingomonas sp. R1)产生了一种不同于结冷的异常外源性
鞘氨醇多糖(表示为HWR1)。结冷中的
鼠李糖被HWR1中的
甘露糖取代。该细菌具有独特的细胞表面,表面覆盖着许多复杂的褶皱。从在
柚皮苷存在下生长的Sphingomonas sp. R1中纯化的α-
L-鼠李糖苷酶是一种单体,分子质量为110 kDa,在pH 8.0和50°C时活性最高。该酶需要二价
金属离子才能发挥活性,并从各种
鼠李糖苷中释放出
L-鼠李糖。