生物合成乳链菌肽及其螯合物的研究

从酸奶中筛选到一株乳链菌肽产生菌A1-06,研究了各种条件因素对其合成能力的影响。通过发酵培养基的优化,在以质量分数2.0%的蔗糖为唯一碳源、0.25%的酵母膏为唯一氮源条件下,A1-06合成乳链菌肽的产率为0.3 g.L-1,效价为1.018×106U.L-1,比在基础培养基中合成的活性提高17%。Mn2+对A1-06的合成能力有抑制作用,而吐温-80则有促进作用。对乳链菌肽及其Zn2+和Fe2+的螯合物的抑菌效果进行了比较,结果表明,乳链菌肽螯合Fe(Ⅱ)对G-菌有抑制作用,6 h的抑菌率为50.3%,而乳链菌肽、乳链菌肽螯合Zn(Ⅱ)对G-菌无明显的抑制作用。

Study on Biosynthesis of Nisin and Its Chelates

A strain of Lactococcus lactis named A1-06 was isolated from sour milk,and some factors influenced biosynthesis of nisin were studied.Through the optimization of the fermentation medium,the yield of nisin synthesized by A1-06 was 0.3 g·L-1 and the bioavailability was 1018 U·mL-1 under the conditions of 2.0% sucrose and 0.25% yeast extraction,which increased 17% compared with the activity of nisin synthesized in the original medium.The results indicated that A1-06 growth and nisin biosynthesis were restrained by Mn2+,but increased by tween-80.The experiments demonstrated that Nisin-Fe(Ⅱ) chelate had suppression to G-bacteria,the antibacterial rate was 50.3% within 6h.But nisin and Nisin-Zn(Ⅱ) chelate did not show the antibacterial activity to G-bacteria.