粪肠球菌铁富集能力研究

Iron enrichment ability of Enterococcus faecalis

【目的】研究耐铁粪肠球菌X4对铁的富集能力,为开发生物有机铁制剂提供依据。【方法】采用单因素试验,以粪肠球菌X4菌体产量和铁富集率为指标,对影响X4铁富集性能的铁离子质量浓度、铁加入时间、X4菌液接种量、培养时间、碳源及氮源种类等发酵条件进行初筛;再采用L_(18)(3^(7))正交试验,以铁富集率为指标,对最佳碳源、氮源添加量及上述其他发酵条件进一步优化;最后在优化的发酵条件下进行15 L发酵罐模拟试验,对X4的铁富集性能进行评价。【结果】粪肠球菌X4铁富集最优发酵条件为:铁离子质量浓度650 mg/L,培养16 h加铁,X4菌液接种量为体积分数18%,培养时间84 h,可溶性淀粉添加量20 g/L,酵母膏添加量15 g/L,氯化铵添加量4 g/L。最优发酵条件下的发酵罐模拟试验结果显示,耐铁粪肠球菌X4的单位菌体产量为5.52 g/L,单位菌体铁富集量101.38 mg/g,铁富集率86.16%,单位菌体有机铁富集量12.67 mg/g,铁有机化率12.5%。【结论】从铁富集量、铁富集率和铁有机化率来看,耐铁粪肠球菌X4具备生产生物有机铁制剂的潜力。

【Objective】The enrichment ability of iron by Enterococcus faecalis X4 was studied to provide basis for development of biological organic iron preparation.【Method】Single factor tests were conducted to optimize concentration of iron,time of iron addition,amount of inoculation,culture time,types of carbon and nitrogen sources as well as amount of iron.Then,the orthogonal experiment was carried out to study the effects of these factors on the enrichment of iron in E.faecalis X4.The iron enrichment performance of X4 after 15 L fermentation tank simulation test was evaluated.【Result】The obtained optimal fermentation conditions of E.faecalis X4 were iron ion concentration 650 mg/L,iron addition time 16 h,inoculation amount 18%,culture time 84 h,soluble starch 20 g/L,yeast extract 15 g/L,and ammonium chloride 4 g/L.The fermentation tank simulation test showed that yield per unit cell,iron enrichment per unit cell,iron enrichment rate,organic iron and iron organification rate of iron resistant E.faecalis X4 were 5.52 g/L,101.38 mg/g,86.16%,12.67 mg/g and 12.5%,respectively.【Conclusion】In terms of iron enrichment,iron enrichment rate and iron organification rate,iron resistant enterococcus faecalis X4 has the potential to produce bio-organic iron preparations.