降解海上溢油残油的“复合微生物导弹”机制和应用基础

The “composite microbial missile”, is short for degradable lipophilic-outside/ hydrophilic-inside porous nanomaterial carrier that immobilized with composite microbial. The research of rapid removal of oil-spill pollution is a common focus all over the world. Bioremediation is the most safe and effective method, especially towards the thin oil film, emulsified oil on the sea surface and residual oil in the beach that are difficult to clean using physical and chemical method. At present， most researches are focus on screening of highly efficient petroleum degrading strains in laboratory, but few researches the construction of microbial targeting system for residue spilled-oil biodegradation. We plan to use the screened highly efficient petroleum degrading microorganisms in this research. Then, an artificial neural network model to optimize the ingredients for culture of multiple microorganisms will be established so as to construct a relatively stable symbiotic proliferated micro-ecosystem In order to reduce the antagonism with native microbes in application site, an idea based on “missile drug” concept is projected for tracing dispersed oil by lipophilic carrier. The carrier is a lipophilic-outside/hydrophilic-inside nanomaterial for immobilization of microorganisms, which promote multiple microorganisms growing and reproducing in the oil/water interface and biodegradation residue oil. Then, we plan to obtain the secreted secondary metabolites as lead compound, to research the emulsification and trans-membrane transport pathway for explain the biodegradation mechanism. The research will provide a new approach for removal of residual oil by microbiological method. The degradation theory will provide reliable scientific basis for the elimination of residual oil.

“复合微生物导弹”是可降解的亲油包水多孔纳米材料作为复合微生物固定化载体的简称。快速清除溢油污染是全世界共同关注的焦点，特别是物理法和化学法难处理的海面薄油膜、乳化油和沙滩残留油，生物修复法最安全有效。目前的研究多停留在高效石油降解菌种的实验室筛选上，而对构建微生物靶向性降解残油系统研究甚少。本申请使用前期筛选的高效石油降解菌种，通过建立人工神经网络模型优化复合微生物的培养基配方，形成相对稳定、共生增殖的微生态系统；为了减少应用现场与本土微生物产生拮抗作用，以“导弹药物”思路研制一种能追踪分散油污的亲油载体，这种亲油包水的纳米材料作为固定化微生物的载体，使复合菌群在油水界面上快速繁殖、高速高效降解残油；进而获取微生物分泌的次生代谢产物作为先导化合物，研究乳化作用和跨膜运输方式，用于解释降解作用机制。该研究将为微生物法清除残油提供新途径，阐述的降解理论将为消除残油提供可靠的科学依据。

针对生物法处理溢油存在三个关键问题，项目围绕菌群、载体和溢油降解性能的影响规律开展研究，主要研究结果如下：(1)选育降解石油的菌种，研制混合菌种的培养液配方，建立相对稳定的复合微生态系统，解决溢油多组分的同时降解问题。从溢油污染的海滩沉积物中分离得到高效石油烃降解菌复配构成菌群。菌群在降解过程中存在协同效应，可同时降解溢油中的多组分。(2)制备了一系列新型微生物导弹，解决生物降解效率低的问题。制备了大孔微生物导弹、聚乳酸型微生物导弹和磁性微生物导弹，该技术可推广应用于处理船舶机舱产生的乳化油废水。微生物导弹比游离态菌群12 h处理乳化油的降解率提高了13.86%，体现了反应启动快、处理效率高的特点。（3）残油降解工艺的应用基础研究，采用实验数据验证经典动力学方程的适用性，通过吸附动力学分析，证明粒子内扩散并不是吸附过程的唯一速率控制步骤。降解动力学验证了菌群对菲的吸附速率远大于其降解速率，促使其降解速率远大于其溶解速率，推断出溶解过程是菌群降解溢油的限速步骤。（4）分离纯化菌群的次生代谢产物，得到高纯度的鼠李糖脂作为导化合物，研究乳化作用和跨膜运输方式，通过水杨酸和邻苯二甲酸两条代谢途径，菌群最终完全降解溢油。（5）通过本项目研究，培养了博士生2名（2名毕业），硕士5名（2名毕业）；发表SCI/EI/核心论文16篇，出版论著2本，发明专利5项，获奖4项，尚有多篇论文正在修改与投稿之中。项目的研究成果可为大规模的菌群应用于海洋溢油污染治理提供具有普适性的理论和技术支持。