酵母膏对α溶血性链球菌发酵代谢甘露聚糖肽的影响

Effect of yeast extract on Mannan peptide byα- Hemolytic streptococcus

研究发酵培养基中酵母膏的添加量对α-溶血性链球菌生长及其代谢甘露聚糖肽的影响规律。结果表明：当酵母膏的添加量小于7g/L时,随着酵母膏添加量的增加,α-溶血性链球菌的菌落数明显增加,最大菌落数为1.9×109,比对照组7.6×108增加了1.5倍,而且α-溶血性链球的延迟期由8h缩短到5h之内,对数期的生长速率由2.83增加到11.02,进入稳定期的时间也由27h以上缩短到23h。当酵母膏添加量大于7g/L时,这一规律就不再明显。同时,酵母膏使菌体量快速增加的时间提前了2-4h,当酵母膏添加量为7g/L时,在发酵4h时,比生长速率最大,为0.38;在发酵27h时,甘露聚糖肽的代谢量最大,为1.04g/L。

The effect of amounts of yeast extract in fermentation medium on growth and metabolism of co-hemolytic streptococcus were studied. The results showed that： the number of colonies of a-hemolytic streptococcus increased obviously with the amount of yeast extract when the amount of yeast extract was from 3g/L to 7g/L,the most number of colonies was 1.9×10^9, 2.5 times as high as the control group 7.6 × 10^8. The lag phase of a-hemolytic streptococcus reduced from 8h to less than 5h.The logarithmic growth rate increased from 2.83 to 11.02. And the stationary phase reduced from more than 27h to 23h.When the yeast extract content was more than 7g/L,those rules were no longer apparent.At the same time,the yeast extract made bacteria volume increase rapidly ahead of time for 2-4h.The largest specific growth rate was 0.38 at fermentation time 4h,and the maximum yield of mannan peptide was 1.04g/L at fermentation time 27h when the yeast extract content was 7g/L.