淡腌青鱼中木糖葡萄球菌碳源代谢能力研究

Potential of Staphylococcus xylosus Isolated from Lightly Salted Mylopharyngodon piceus to Utilize Carbon Sources

摘要:

为探究淡腌青鱼的腐败与其微生物代谢能力的关系，利用Biolog GEN Ⅲ 微孔板对淡腌青鱼货架期终点的特定腐败菌(木糖葡萄球菌)在5、15、25、33℃ 4种温度下的碳源利用情况进行研究，采用修正的Gompertz模型对代谢曲线进行拟合，并以平均颜色变化率(AWCD)为指标研究其代谢速率，分析木糖葡萄球菌利用碳源能力的动力学特征。结果表明：木糖葡萄球菌能利用糖、氨基酸和羧酸类等碳源；相同温度下木糖葡萄球菌对碳源的代谢能力由大到小依次为糖、羧酸、氨基酸，其中单糖（葡萄糖、甘露糖）、双糖（蔗糖、海藻糖）、多糖及其糖类衍生物(N-乙酰-β-D-甘露糖胺、β-甲酰-D-葡糖)、氨基酸（谷氨酸、丝氨酸）和羧酸（L-乳酸）的代谢较强。木糖葡萄球菌在25℃下的延滞期最短，进入指数期最快。通过对木糖葡萄球菌在不同温度下各种碳源代谢能力的分析，为优化产品配方有效抑制微生物的活动、延长产品货架期提供理论依据。

Abstract:

With the purpose to investigate the relationship between spoilage and bacterial metabolism in lightly salted Mylopharyngodon piceus, Biolog GEN Ⅲ microplate was used to understand the carbon metabolism of predominant spoilage bacteria, Staphylococcus xylosus, at 5℃, 15℃, 25℃ and 33℃, respectively, and the growth curve of Staphylococcus xylosus was fitted with the modified Gompetz model. In addition, the metabolic rate was measured by using average well color development (AWCD) as indicator to describe its dynamic properties of carbon utilization. The results showed that saccharides, carboxylic acids and amino acids were utilized by Staphylococcus xylosus with degressive utilization ratio at the same temperature. Among carbon substrates, monosaccharides (e.g., glucose and mannose), disaccharides (e.g., sucrose and trehalose), polysaccharides and sugar derivatives (e.g., N-Acetyl-β-D-Mannose amine and β-Methyl-D-Glucoside), amino acids (e.g., glutamate and serine) and carboxylic acids (e.g., L-lactate) were dramatically metabolized. The lag phase of Staphylococcus xylosus was the shortest at 25℃, thus the exponential phase was reached fast. Overall, the present study focused on carbon utilization and metabolism of Staphylococcus xylosus at different temperatures to provide a theoretical basis for inhibition of microbial activity by optimizing formula and extension of shelf life of lightly salted Mylopharyngodon piceus. It was proposed that Biolog GEN Ⅲ microplate could be applied to establishment of bacterial predictive model combining simultaneous investigation on microbial activity of carbon sources utilization and metabolism.