鹰嘴豆纳豆液态发酵高产蛋白酶的培养基及发酵条件优化

为了提高纳豆中的蛋白酶活力,以纳豆芽孢杆菌为菌种,对鹰嘴豆纳豆液态发酵进行优化。以蛋白酶活力为指标,采用Plackett-Bnrmao法筛选出三个对蛋白酶活力影响最大的因素:装液量、转速和鹰嘴豆粉添加量。通过响应面优化鹰嘴豆纳豆液态发酵的培养基和发酵条件,建立二次回归模型的拟合度良好,对提高蛋白酶活力影响显著(p<0.005),所得最佳培养基为鹰嘴豆粉添加量5.9%,豆粕粉1.0%,葡萄糖0.6%,氯化钠0.5%,最佳发酵条件为:转速250 r/min,装液量76 mL/500 mL,温度37℃,发酵时间48 h。该条件下发酵所得蛋白酶活力达(3558.0±1.5) U/mL,相对于对照培养基的(2491.4±2.8) U/mL提高了42.8%,且纤维蛋白平板法验证的纳豆激酶溶解圈面积提高了108.6%。结果表明,优化后的鹰嘴豆纳豆液态发酵能有效提高蛋白酶活力。

Optimization of submerged fermentation medium and condition of chickpea natto

In order to increase the protease activity in natto,chickpea natto submerged fermentation was optimized with Bacillus subtilis natto in this research,protease activity was taken as determining index and three most effective factors were screened out by Plackett-Burman method:liquid volume, rotate speed and chickpea powder. Response surface method was used to optimize the fementation medium and condition and quadratic regression model.The quadratic regression model that set up in response surface showed the good regression level, which indicated the effect on the improvement of protease activity was significant(p<0.05). The optimization we got for medium:chickpea powder 5.9%, soya bean meal powder 1.0%, glucose 0.6%,NaCl 0.5%, the best incubation condition:rotate speed 250 r/min, liquid volume 76/500 mL, fermented under the condition of 37℃ and 48 hours. The protease activity reached (3558.0±1.5) U/mL and had increased 42.8% under this condition compared with initial(2491.4±2.8) U/mL,while the dissolved area of nattokinase tested by fibrin plate method had also increased 108.6%. The results showed that the optimized submerged fermentation of chickpea natto could significantly improve the protease activity.