产甘露聚糖酶细菌的分离鉴定、酶的部分纯化及酶学性质研究

Isolation, Identification, Partial Purification and Enzymatic Characterization of β-mannanase Producing Strain

以魔芋粉为惟一碳源作为富集条件,利用刚果红染色法从玉米地土壤中筛选到1株产B-甘露聚糖酶的菌株,经摇瓶培养后其酶活力达到101 U/mL.经形态观察及16S rDNA序列分析,鉴定为枯草芽孢杆菌（Bacillus subtilis）.利用硫酸铵分级沉淀、阴离子交换层析和疏水层析对酶进行了部分纯化.对酶的酶学性质研究发现,该酶的最适反应温度为50℃,最适反应pH为5.0;在45～55℃时酶的稳定性较好,保温30 min后其残留活性在80％以上,在pH4.5～5.5时酶的稳定性较好,保持30 min后其残留活性在80％以上.

Using konjac powder as the sole carbon source,a strain producing β-mannanase was isolated from corn field with Congo red dyeing method and identified as Bacillus subtilis with morphological observation and 16S rDNA sequencing.After shaking-flask culture,the enzyme activity of this strain achieved 101 U/mL.By ammonium sulfate fractional precipitation,anion exchange chromatography and hydrophobic interaction chromatography,the enzyme was partly purified and studied on its enzymatic properties.The results showed that the optimal reaction temperature and pH of the produced β-mannanase were 50 ℃ and 5.0,respectively.The enzyme had a good stability under temperature from 45 to 55 ℃ and pH from 4.5 to 5.5,with the enzyme activity remained over 80% for 30 min.