嗜热碱性果胶酶产生菌的筛选及产酶条件优化

从极端土壤中分离到1株高效产碱性果胶酶菌株RH214,经鉴定为Bacillus smithii。为了进一步提高其产果胶酶活性,对产酶的培养基成分进行了优化。首先采用单因素试验筛选出最佳碳源为可溶性淀粉,最佳氮源为蛋白胨,金属盐为KH2PO4。根据单因素结果确定可溶性淀粉浓度、蛋白胨浓度和KH2PO4浓度为主因素,利用Box-Behnken试验设计和响应面法分析确定各因素的最优水平,得出菌株RH214的最优产酶条件:可溶性淀粉的浓度为85.6 g/L、蛋白胨浓度11.8 g/L、KH2PO4浓度为3.8 g/L、酵母粉1 g/L、FeSO41g/L、KCl 0.5 g/L、起始pH9.0、装液量80 mL/250 mL、温度40℃、摇床转速150 r/min,培养时间为16 h。在此条件下,进行验证实验,获得产酶活性为(88±0.86)U/mL,比未优化前的20.50 U/mL提高了4.3倍。

Screening and Optimization of Bacillus smithii RH214 for Pectinase Activity

A stain RH214 with high ability to produce pectinase was isolated from soil and identified as Bacillus smithii.In order to improve the production of pectinase,some fermentation conditions were optimized.According to single-factor experiments,the optimal carbon source,nitrogen source and salt were determined to be soluble starch,peptone,and KH2PO4 respectively.As the key factors,these single factors(soluble starch,peptone and KH2PO4) were further optimized by Box-Behnken design and response surface methodology.A maximum pectinase activity of(88 ±0.86) U/mL was obtained using the condition as follows: after 16 h fermentation of 80 mL fermentation medium containing soluble starch 85.6 g/L,peptone 11.8 g /100 mL,KH2PO43.8 g/L and FeSO41 g/L,KCl 0.5 g/L at an initial pH of 9.0,fermentation temperat.ure 40℃ with 150 r/min shaking.Under these conditions,the activity production was 4.3 times higher than the initial production(20.50 U/mL) before optimization.