产脲酶细菌的固定化及转化条件研究

目的]研究1株高产脲酶的芽孢杆菌菌体的固定化及其固定化细胞的转化条件。方法]研究不同浓度海藻酸钠溶液、菌体包埋量、戊二醛溶液对固定化细胞脲酶酶活的影响,以及不同pH值、不同温度、几种离子浓度对脲酶活力的影响。结果]结果表明,固定化细胞转化最适pH值为7.5,最适温度为40℃,最适海藻酸钠溶液浓度为30 g/L,最佳包埋量为40 g/L,最适戊二醛浓度为2%;细胞经过固定化后,细胞脲酶稳定性显著提高,经过戊二醛交联后,稳定性再次提高。固定化细胞的脲酶对Cu2+、Hg2+的抑制作用有一定的抗性。结论]固定化细胞比游离细胞更适合工业化操作。

The Technology of Immobilizing Cell Producing Urease and Properties of Urease

Objective]This paper aimed to study the immobilization of cell producing urease and properties of urease.Method] The effects of sodium alginate,entrapped cell quantities and glutaral dehyde on urease activity of immobilized cell were studied.The effects of pH value,temperature and metal ions on biotransformation were also studied.Result] The optimum pH value of the urease of immobilized cell and temperature were 7.5 and 40 ℃,respectively.The urease activity of immobilized cell and recovery ratio got optimum results when the concentration of sodium alginate was 30 g/L.The best entrapped cell quantities was 40 g/L and the urease of immobilized cell was more stable than that of free cell.When the concentration of glutaraldehyde was 2%,crosslinked immobilized cell showed maximum urease activity and more stability than immobilized cell before crosslinking.The immobilized cell showed remarkable resistance to inhibition of Cu2+ and Hg2+.Conclusion] The urease of immobilized cell performanced better than that of free cell.