| 强化固定化Methylibium petroleiphilum PM1细胞降解MTBE及动力学特性分析 |
| 摘要点击 2907 全文点击 1701 投稿时间：2010-05-13 修订日期：2010-09-28 |
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| 中文关键词 MTBE 强化固定化细胞 响应面 使用批次 降解动力学 |
| 英文关键词 methyl tert-butyl ether (MTBE) stabilized immobilized cells response surface methodology batches biodegradation kinetics |
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| 中文摘要 |
| 采用海藻酸钙包埋固定化高效降解菌Methylobium petroleiphilum PM1降解水相中的甲基叔丁基醚（MTBE），考察了不同强化方法对凝胶颗粒机械强度和降解活性的影响. 响应面结果表明，交联剂和培养基中Ca2+浓度分别为0.2 mol·L-1和1.38 mmol·L-1，化学交联剂聚乙烯亚胺（PEI）浓度为0.1%时，强化固定化细胞具有较高的降解活性. 在此条件下，凝胶颗粒在24 h内机械破碎率仅为5.98%，并能连续使用400 h以上，未出现颗粒溶解破碎现象，降解速率较为稳定. 扫描电镜观察，PEI处理后的凝胶颗粒表面形成一层薄膜，能有效防止细胞泄漏，并能维持PM1细胞良好的生长繁殖. 动力学分析表明，降解的限速步骤为生化反应，直径3 mm凝胶颗粒对底物的扩散限制最弱；而高浓度的PEI能引起严重的扩散限制现象. |
| 英文摘要 |
| Methylibium petroleiphilum PM1,which is capable of degrading methyl tert-butyl ether (MTBE),was immobilized in calcium alginate gel beads. Several methods were explored to increase the strength of these gel beads. The central composite design analysis indicated that the introduction of 0.2 mol·L-1 Ca2+ into the crosslinking solution,1.38 mmol·L-1Ca2+ into the growth medium and 0.1% polyethyleneimine (PEI) as the chemical crosslinking agent could increase the stability of the Ca-alginate gel beads with no loss of biodegradation activity. The stabilized immobilized cells could be used 400 h continuously with no breakage and no bioactivity loss. Examination of scanning electron microscope demonstrated that a membrane surrounding the gel beads was formed and the cells could grow and breed well in the stabilized calcium alginate gel beads. Kinetic analysis of the gel bead-degradation indicated that the rate-limiting step was biochemical process instead of intraparticle diffusion process. The diameter of 3 mm affected the biodegradability less while high concentration of PEI induced much more serious mass transfer restraint. |
