铜绿假单胞菌NY3胞外分泌物对降解烃类的影响作用

摘要

The influence of extracellular excretion on degradation rate of hydrocarbon was studied in order to understand the effect of extracellular excretion on hydrocarbon degradation by Pseudomonas aeruginosa NY3.It was found in the study that the seed solution of NY3 cultured and grew on LB medium with hydrocarbon as the sole carbon source and inorganic salt,the efficiency of hydrocarbon metabolism of the bacterial cell after centrifuge and wash significantly declined.Extracellular macromolecule and small molecule extracted from seed solution supernatant respectively with salt-outing and solvent extraction was plunged into NY3 cells (the cells after centrifuged) inorganic salt medium for degrading tetradecane,extracellular macromolecule compound was found within 24 h make the depletion rate of tetradecane by NY3 cells to increase by 14％.While the one plunged into NY3 cells within 24 h with small molecule compound within 24 h make the depletion rate of tetradecane by NY3 cells to increase by 6％.Extracellular macromolecules of the NY3 cells were isolated and identified by SDS-page polyacrylamide electrophoresis.It was found that they were proteins or polypeptides,mainly there were bands and their molecular weight is within about the range of 35-55 kD.The enhancement mechanisms of its hydrocarbon degradation remained to be proved further.Small molecule secretion was identified by flight mass spectrometer (LCMS-IT-TOF).The results showed that under the conditions of present experiment,they were all oxidation-reduction active substance that could accelerate the electron transferring rate in the reaction system,to enhance oxidation-reduction reaction of substrate.%为了研究铜绿假单胞菌Pseudomonas aeruginosa NY3胞外分泌物对烃类降解的作用,对胞外分泌物影响烃类降解的效率进行了研究.研究发现,NY3菌以LB培养基和以烃类为唯一碳源的无机盐培养基培养得到的种子液,离心并洗涤菌体后,菌细胞代谢烃类效率明显下降.分别利用盐析和溶剂萃取法,提取种子液上清液中胞外大分子和小分子,且投加在NY3菌(离心后的菌细胞)降解十四烷的无机盐培养基中,发现24 h内外加胞外大分子化合物,使NY3菌对十四烷去除率可提高约14％,而投加小分子化合物使NY3菌24 h内对十四烷去除率提高约6％.利用SDS-page聚丙烯酰氨凝胶电泳分离胞外大分子,结果发现主要是该菌胞外所分泌的蛋白或多肽类,主要有3个条带,它们的分子量约在35～55 kD范围内,其对烃降解促进作用机理有待进一步验证.利用飞行质谱(LCMS-IT-TOF)鉴定胞外小分子分泌物,结果表明在本研究条件下,它们均为氧化还原反应活性物,可以加快反应体系中电子传递速度,促进底物的氧化还原反应.