鱼源莓实假单胞菌生长动力学与碳源利用分析

Growth Kinetics and Carbon Utilization Analysis of Pseudomonas fragi from Fish

以鱼源莓实假单胞菌为研究对象,利用BIOLOG获得15、25、33℃下其GEN III板中碳源生长数据,采用修正的Gompertz模型,结合孔平均颜色变化率及利用面积,分析其碳源利用效果,并对3个温度下pH值、NaCl和乳酸钠(NaL)的抑菌效应和生长动力学进行研究。结果表明,25℃时莓实假单胞菌总体碳源利用能力和活性最强,15℃时次之,33℃时最弱。在15~33℃内,碳源利用以糖类、羧酸类和氨基酸类为主。糖类中利用较好的有α-D-葡萄糖、L-岩藻糖等;氨基酸类中利用较好的有L-焦谷氨酸、L-丙氨酸、L-谷氨酸;羧酸类中利用较好的有奎宁酸、D-葡糖酸、糖质酸等。15~25℃下4%~8%NaCl及33℃下1%~8%NaCl对莓实假单胞菌皆有抑制作用。33℃时pH值对莓实假单胞菌生长起抑制作用,1%的NaL对其具有促进作用。通过对莓实假单胞菌抑菌效应和碳源利用分析,可为优化产品配方和保障产品质量提供理论依据。

Pseudomonas fragi is one of the specific spoilage organisms（SSOs） in aquatic food,especially in refrigeration stage.Aiming to investigate carbon utilization of P.fragi at different temperatures and study the effect of pH value,NaCl and sodium lactate on growth of P.fragi based on the kinetics of colour formation.Firstly,bacterial suspension was inoculated in Biolog GEN III plates,respectively incubating at different temperatures（15℃,25℃ and 33℃）.Then the data were fitted by the modified Gompertz equation and kinetic parameters were estimated.Through kinetic parameters（maximum specific growth rate and lag phase）,and combining utilization area（S） and average well colour development（AWCD） value,the effect of carbon source utilization at different temperatures and environment factors on P.fragi was analyzed.Results showed that at 25℃ P.fragi had the highest carbon utilization and activity ability,which was followed by 15℃,and the lowest value was got at 33℃.At 15 - 33℃,P.fragi mainly used carbohydrates,amino acids and carboxylic acids.Moreover,the effect of changes of different temperatures on various kinds of carbon sources utilization was obvious,while the effect of changes of different temperatures on utilization rates was not obvious.In carbohydratesα-D-glucose,L-fucose,sucrose and D-mannitol could be better utilizated.In amino acids L-pyroglutamic acid,D-serine,L-alanine,L-glutamic acid could be better utilized.And in carboxylic acids quinic acid,D-gluconic acid,D-glucuronic acid,D-saccharic acid,L-malic acid were better utilized.At 15℃ the pH value was kept at 6.0 or 5.0,which the color maximum rates of color development were close,while at25℃,pH value of 6.0 was far greater than at pH value of 5.0,and at 33℃ at any pH value,the growth of P.fragi was inhibited.At 15 - 25℃,4% - 8% NaCl and at 33℃,1% - 8% NaCl or pH value of6.0 or pH value of 5.0,the growth of P.fragi was inhibited,and at 15 - 25℃,1% NaCl or pH value of 6.0,pH value of 5.0 and at 33℃,1% NaL the growth of P.fragi was promoted.The antibacterial effect on P.fragi and carbon utilization was analyzed which can provide a theoretical basis for optimizing product formulation and guaranteeing product quality.