冷榨核桃粕固态发酵制备纳豆激酶

Nattokinase Production from Cold-Pressing Walnut Dregs by Solid-state Fermentation

因冷榨核桃粕营养价值高,故探讨以冷榨核桃粕为主要原料,采用纳豆芽孢杆菌进行固态发酵制备纳豆激酶的方法。通过单因素试验、Plackett-Burman(PB)试验和Box-Behnken(BBD)响应面法确定最佳工艺参数。以纳豆激酶活性为指标,单因素试验表明核桃粕粒度小于10目,葡萄糖和Na Cl添加量分别为1%和1.5%,浸泡时间2 h,蒸煮时间50 min,接种量11%,后熟时间24 h时,纳豆激酶活性相对较高。PB试验表明料液比、发酵时间和发酵温度对纳豆激酶活性影响显著。采用BBD响应面分析法对关键因素进行优化,得到最佳工艺参数:料液比1∶1.5、发酵时间30 h、发酵温度36℃。此发酵条件下纳豆激酶活性达到最大值1 522 U/g。本试验表明:纳豆芽孢杆菌固态发酵冷榨核桃粕是制备纳豆激酶的有效方法。

Cold-pressing walnut dregs contained high nutritional value. In this study, nattokinase production from cold-pressing walnut dregs through solid-state fermentation by Bacillus subtils natto was investigated. In order to obtain higher nttokinase activity, the process parameters were optimized by Single-factor experiment, Plackett-Burman（PB） design and Box-Behnken（BBD） response surface methodology. Based on nttokinase activity the result of Single-factor test showed that higher nttokinase activity was observed with smaller than 10 mesh of walnut dregs, 1% of glucose, 1.5% of Na Cl, 2 h of soaking time, 50 min of steaming time, 11% of inoculation amount or 24 h of ripening time. PB design showed that the key factors affecting nattokinase activity were the ratio of solid to liquid, fermentation time and fermentation temperature. Furthermore, the optimum production parameters were obtained by Box-Behnken response surface methodology as fellows： the ratio of solid to liquid was 1 ∶1.5, fermentation time was 30 h and fermentation temperature was 36 °C, and thus the highest activity of nattokinase was observed with 1 522 U/g. It＇s an effective method to product nattokinase from cold-pressing walnut dregs by solid-state fermentation of Bacillus subtils natto.