Paenibacillus spp.BD3526发酵小麦麸皮生产凝乳酶

Study on milk-clotting enzyme produced by Paenibacillus spp.BD3526 in wheat bran broth

对Paenibacillus spp.BD3526凝乳酶的发酵条件和凝乳性能进行了研究,探讨了不同培养基、发酵时间、碳源、氮源和装液量对凝乳酶活力和活菌数的影响,并与商业化的小牛皱胃酶、重组凝乳酶、Rhizomucor miehei来源凝乳酶进行凝乳性能比较。实验结果表明:发酵时间、碳源、氮源和装液量对BD3526凝乳酶活力(milkclotting activity,MCA)和蛋白水解活力(proteolytic activity,PA)均有不同程度的影响。选用小麦麸皮培养基进行发酵至24 h时,MCA达到最大至3 279.76±67.11 SU/m L,凝乳性能强,PA值在整个发酵期间变化不大;添加碳源或氮源会不同程度地降低MCA值;装液量为30 m L时,发酵上清液中菌体浓度最高、MCA达到6 000 SU/m L。与商业化的凝乳酶相比,BD3256凝乳酶在凝乳过程中未使凝乳块产生过度水解,也无乳清析出现象,具有应用到干酪生产中的潜力。

Proteinase with milk-clotting activity（ MCA） produced by Paenibacillus spp. BD3526 in fermented wheat bran broth were studied. The effects of different mediums,fermentation time,carbo sources,nitrogen sources and liquid volume in flask on MCA and proteolytic activity（ PA） were discussed in this paper. The results indicated that MCA reached 3279. 76 ± 67. 11 SU / m L and showed excellent coagulation property after fermentation in wheat bran broth for 24 hours. Addition of carbo source and nitrogen source would reduce MCA. The biomass,MCA and PA reached maximum when liquid volume in flask was 30 m L. No excessive hydrolysis of curds and whey syneresis were found after 40 minutes of coagulation of curd with BD3526 enzyme in comparison with the commercial coagulants,which suggested that it would have a great potential application in the cheese production.