摘要
采用正交试验设计优化了解淀粉芽孢杆菌GSBa-1发酵产凝乳酶的工艺条件:发酵温度35℃,装液量40%,摇床转速180 r/min,发酵时间84 h。在此优化条件下,获得的凝乳酶凝乳活力为558.14 Su/m L。进一步研究了该酶的酶学性质,凝乳酶最适反应温度为55℃,酶活力在25~45℃比较稳定,60℃保持50 min完全失活。在p H5.5时凝乳酶活力最高,在pH 5.5~7.0范围内,随着pH增大,凝乳酶活力逐渐下降,p H 6.5时,凝乳酶活力稳定性最高。Ca^(2+)、Mg^(2+)、Fe^(2+)、Zn^(2+)以及Al^(3+)均对凝乳酶的凝乳活力有促进作用,其中Ca^(2+)对凝乳活力的促进作用最为显著,且Ca^(2+)浓度为0.020 mol/L时凝乳酶的凝乳活力达到最大值,而Na^+、K^+和Cu^(2+)对凝乳活力均有抑制作用;凝乳酶Km为2.35 g/L,Vmax=1.18 U/m L。
In this paper, fermentation conditions for the rennet production from Bacillus amyloliquefaciens GSBa- 1 were optimized by the orthogonal experimental design method. The optimal conditions were as follows： fermentation temperature of 35 ℃, liquid loading volume of 40% , shaking speed of 160 r/min, fermentation time of 84 h. The milk-clotting activity of the enzyme produced under the optimal condition was 558.14 Su/mL. The rennet from Bacil- lus amyloliquefaciens GSBa-1 was prepared and further studies were carried out on factors affecting enzymological char- acteristics of the rennet. Results showed that the optimum reaction temperature was 55 ℃, the enzyme activity was stable between 25 -45℃ , and incubation at 60℃ for 50 min resulted in complete loss of enzyme activity. The ren- net presented the highest enzymatic activity at pH5.5, then it gradually decreased with the increase of pH from 5.5 to 7.0, and the enzyme activity of rennet was the most stable at pH 6.5. The rennet activity was positively affected by Ca2＋ , Mg2＋ , Fe2＋ , Zn2＋ and Al3＋ , of which Ca2＋ showed the most significant promoting effect, and the milk-clot- ting activity reached maximum at Ca2＋ concentration of 0.02 mol/L, while Na＋ , K ＋ and Cu2＋ showed inhibition effect on the milk-clotting activity. The km and Vmax of the enzyme were 2.35 g/L and 1.18 U/mL, respectively. Key words Bacillus amyloliquefaciens; rennet; orthogonal experimental design method; enzymological characteris- tics
出处
《食品与发酵工业》
CAS
CSCD
北大核心
2016年第12期83-89,共7页
Food and Fermentation Industries
基金
国家自然科学基金面上项目(编号:31371804)
北京市百千万人才工程资助项目(B类)
2016年北京工商大学研究生科研能力提升计划项目
关键词
解淀粉芽孢杆菌
凝乳酶
正交试验
酶学性质
Bacillus amyloliquefaciens
rennet
orthogonal experimental design method
enzymological characteristics
