【摘要】 从云南省元阳地区采集豆豉样品,并从中分离得到62株乳酸菌菌株。通过脱脂乳平板试验,从中初步筛得到21株具有高蛋白酶活力的菌株,采用茚三酮法测定其蛋白酶活力,复筛出高产蛋白酶菌株YY-1-6L,并对其产酶条件进行研究。结果表明,YY-1-6L在以葡萄糖为碳源、多聚蛋白胨为氮源、起始pH 5.0的明胶诱导培养基中,接种量为3%,35℃发酵培养36 h,其蛋白酶活力高达32.50 U/mL,且K2HPO4、MgSO4能促进蛋白酶产生。更多还原

【Abstract】 Douchi(fermented soybean) samples were collected from Yuanyang region in Yunnan Province.62 strains of lactic acid bacteria were isolated from these samples,21 strains with high protease activity were screened by detecting the clear zone on the defatted milk plate.Ninhydrin method was used to determine the protease activities of these strains and a high-yield strain YY-1-6L was obtained.And the conditions of enzyme production of the strain was studies.The experimental results revealed that the optimal conditions for the strain to produce proteinase were as follows: glucose as carbon source,and polypeptone plus yeast powder as nitrogen sources,initial pH 5.0,inoculum size 3%,fermentation temperature 35 ℃ and fermentation time period 36 h.Under these conditions,the yield of proteinase was 32.50 U/mL.It was also found that K2HPO4 and MgSO4 could promote proteinase-producing.更多还原