摘要
乳酸菌因自身特性和分泌多种代谢物而在发酵过程中起重要的作用.从泡菜中筛选出2株高产β-葡萄糖苷酶乳酸菌,经16S rRNA基因测序比对后均鉴定为植物乳杆菌(命名为PC7-C6和PC7-C11).随后对2菌株的益生特性以及酶产量较高的PC7-C11的酶学特性进行分析.结果显示:2菌株为γ-溶血,对氨苄西林、克拉霉素敏感,对四环素、红霉素和克林霉素中度敏感;可在pH 4条件下生长;培养8h后自聚集率在50％～64％范围,与大肠杆菌共聚集率均大于60％;对乙酸乙酯的疏水率分别为70.41％,61.19％,对二甲苯和正己烷的疏水率在30％～40％范围;能够抑制大肠杆菌、蜂房哈夫尼菌、腐生葡萄球菌、粘质沙雷氏菌和马胃葡萄球菌等细菌的生长;PC7-C11的抗氧化能力优于PC7-C6,PC7-C11对DPPH自由基清除率和羟自由基清除率分别为59.33％和53.49％.植物乳杆菌PC7-C11菌株酶活力的最适反应温度40 ℃、最适pH值7,乙醇、葡萄糖、二甲基亚砜、SDS、EDTA、Fe2+、Mg2+、Na+、Ca2+会不同程度地抑制酶活,K+对酶活力有一定的促进作用.
Abstract
Lactic acid bacteria play an essential role in fermentation due to their characteristics and secretion of various metabolites.In this study,two lactic acid bacteria with high β-glucosidase activities were screened from kimchi and i-dentified as Lactobacillus plantarum PC7-C6 and PC7-C11).The probiotic characteristics of the two strains and the en-zymatic characteristics of PC7-C11 which has higher enzyme production ability,were analyzed.The results showed that the two strains were γ-hemolysis,sensitive to ampicillin and clarithromycin,moderately sensitive to tetracycline,ery-thromycin,and clindamycin,and could grew at pH 4.The auto-aggregation rate of the two isolates ranged from 50％to 64％,and the co-aggregation rates with Escherichia coli were more than 60％after co-incubating for 8 hours.The hy-drophobicity of the isolates towards ethyl acetate was 70.41％and 61.19％,and the hydrophobicity of the isolates towards xylene and n-hexane was between 30％and 40％.The two isolates could inhibit the growth Escherichia coli,Haffnia alvei,Staphylococcus saprophytic us,Serratia marcescens,and Staphylococcus equorum.The antioxidant capacity of PC7-C11 was superior to that of PC7-C6,with a 59.33％scavenging rate of 1,1-diphenyl-2-picrylhydrazyl(DPPH)and 53.49％scavenging rate of hydroxyl radicals respectively.The enzymatic characteristics of PC7-C11 showed that the opti-mal reaction temperature and pH for enzyme activity were 40 ℃ and pH 7.Ethanol,glucose,dimethyl sulfoxide,SDS,EDTA,Fe2+,Mg2+,Na+,and Ca2+inhibited enzyme activity to varying degrees,while K+has a certain promoting effect on enzyme activity.
维普
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