壳聚糖酶产生菌的筛选及固定化细胞产酶

旨在筛选得到一株壳聚糖酶产生菌，并研究固定化细胞产酶的条件。在培养基中以壳聚糖为唯一碳源，对土壤样品进行筛选，获得一株无花果沙雷氏菌(Serratia ficaria CH-0203)，该菌可被壳聚糖诱导产生壳聚糖酶。固定化细胞产酶的研究结果表明，多孔玻璃可以有效吸附CH—0203菌细胞。在最适发酵条件下(pH6．5，培养基与载体的总体积48ml，载体与培养基的比例为1．5g/4．0ml，吸附时间是20h-26h)，发酵液酶活达到4．5U／ml，比游离细胞发酵提高了16％。采用半连续发酵的方式，固定化的细胞可以稳定发酵产酶120h左右。固定化细胞产酶的效率大大高于游离细胞。

Screening of Chitosanase- producing Bacteria and Production of Chitosanase by Immobilized Cell

The research aimed to find a strain of chitosanase-producing bacteria,and study the chitosanase-production by immobilized cell.By using chitosan as sole carbon source in culture medium,A strain which may be induced by chitosan to secrete chitosanase,was isolated from soil samples.The strain was identified as Serratia ficaria and was named as CH-0203.Reaearch on production of chitosanase by immobilized cell shows that porous glass may effectively adsorb CH0203 cell.Under optimal conditions (pH6.5,the overall volume is 48ml in a 250ml conical flask,1.5g porous glass/4.0ml culture medium,adsorption time is 20h-26h),the chitosanase activity may culminates 4.5U/ml,which is 16% higher than that of free cell.Adopting the semi-consecutive mode in fermentation,the immobilized CH0203 cell can secret chitosanase steadily for about 120 hours,and is much more effective than free cell fermentation.