3-羟基丙醛耐受菌的筛选与3-羟基丙醛抑菌活力的研究

活化的短乳杆菌用含一定甘油浓度(10 g/L)的平板培养基驯化培养后铺上一层含活化E.coli的培养基,30℃双层平板培养,经7个批次筛选,获得了1株在其周围产生明显抑菌透明圈的短乳杆菌菌落,编号为LB7—6;纯化培养筛选出的短乳杆菌,分别在30℃、37℃下进行二次发酵2～8 h,测定发酵液中3-羟基丙醛(3- HPA)的含量。结果显示,较优化发酵条件为37℃微氧静置发酵6h,在此条件下,3-HPA含量为2.18mg/mL,由此计算得3-HPA总得率为0.147g/g,转化率为19.05%;以10~5个/mL E coil为检测菌,采用比浊法实验,结果表明,发酵所得3-HPA最小抑菌浓度(MIC)为2.18×10~(-3)mg/mL;发酵液40℃保存48 h后测定3—HPA的MIC为2.18×10~0mg/mL,说明所产3-HPA抑菌活力有一定程度的稳定性。

Screening of Strain Endure 3-HPA and Study of 3-HPA Antibacterial Activity

Lactobacillus brevis was acclimatization in flat medium containing glycerol (10 g/L) and then was cultured by double flat layers with medium containing activated E.coli at 30℃.A strain with distinct an- tibacterial circle was screened,and numbered LB7—6.The strain was fermented at 30℃,37℃for 2～8 h by two-steps.The content of 3—hydroxypropionaldehyde (3-HPA) was measured to indicate the optimized con- dition to produce 3-HPA:37℃,fermentation 6h under microaerobic condition without shaking.The content of 3-HPA was 2.18 mg/mL,overall yield was 0.147g/g,conversion rate was 19.05%.E.coli acted as test bacterium with concentration of 10~5 CFU/mL,cultured liquid was detected by absorbency,and the result showed that the minimal inhibitory concentration (MIC) of fermented 3—HPA was 2.18×10~(-3) mg/mL.Af- ter being conserved at 40℃for 48 h,the MIC of 3-HPA was 2.18×10~0 mg/mL.The above findings showed that 3-HPA produced from LB7—6 had certain antibacterial stabilization effect.