发酵鲭鱼中一株组胺降解菌的系统发育分析及特性研究

为筛选出具有优良组胺降解能力的细菌,并探索其在发酵食品中的应用,使用乳酸细菌(MRS)、结晶紫中性红胆盐葡萄糖琼脂(VRBDA)和2216E琼脂培养基对传统发酵鲭鱼(Scomber japonicus)中的组胺降解菌进行分离纯化,测定其生长、产酶特性及对发酵鲭鱼生物胺的降解作用。结果表明,菌株V-TB-2-5具有较高的降组胺活性,通过16S rRNA基因序列系统发育学分析结合形态特征确定为产氮假单胞菌(Pseudomonas azotoformans)。在营养肉汤培养基中,该菌的生长和产酶条件范围为20~40℃、pH值5~8、NaCl浓度0~3.5%(质量分数w/v),最适生长和产酶条件为30℃、pH值6、1.5%NaCl。酶反应的最适条件为30℃、pH值7。Mn²⁺、Mg²⁺和K⁺等金属离子对酶有激活作用,Fe³⁺或EDTA则有抑制作用。在传统发酵鲭鱼中,人工强化接种菌株V-TB-2-5与对照组相比组胺含量明显下降,组胺降解率为18.2%~40.7%;同时,接种组中亚精胺含量下降极显著,而精胺则上升。本研究为菌株V-TB-2-5在水产品加工和贮藏过程中组胺生物降解的控制提供了应用依据。

Phylogenetic Analysis and Characterization of a Histamine-degrading Strain in Fermented Mackerel and Its Growth and Degradation Characteristics

In order to screen out bacteria with excellent histamine-degrading ability, and investigate their application in fermented food, the histamine-degrading bacteria from traditional fermented mackerel(Scomber japonicus) were isolated and purified by MRS medium, VRBDA medium and 2216E agar medium. Their growth, enzyme production characteristics and biogenic amine degradation of fermented mackerel were determined. The results showed that the strain V-TB-2-5 had high histamine-degrading activity, which was identified asPseudomonas azotoformans by 16S rRNA gene sequence phylogenetic analysis and morphological characteristics. The strain exhibited good growth and enzyme activity at 20~40℃, pH5~8 and 0~3.5% sodium chloride in nutrient broth medium, and the optimum growth and enzyme production conditions were 30℃, pH 7 and 1.5% sodium chloride. The optimum conditions for enzyme activity were 30oC and pH 7. The addition of Mn²⁺, Mg²⁺ or K+ stimulated the histamine-degrading activity significantly. However, Fe3+ or EDTA exhibited different degrees of inhibitory activities. When artificially inoculated in fermented mackerel, the strain V-TB-2-5 showed significant histamine-degrading activity with degradation rate of 18.2%~40.7% compared to the control group. Meanwhile, spermidine in the inoculated group decreased significantly, while spermine in the inoculated group decreased on the contrary. This study provides a theoretical and practical basis for the control of histamine biodegradation by strain V-TB-2-5 during the processing and storage of aquatic products.