The Degradation Spectrum And Function Genes In Metabolism Pathway Of Ibuprofen Degradable Strains

Ibuprofen attributed to nonprescription drugs was widely used as anti-inflammatory drug on account of its low toxicity and side effects.However,the trace contaminants were detected frequently in the environment by the innovatory measurement technology.In order to reduce the potential harm and combined pollution of benzene series,we explored the degradation spectrum and the fuction genes of ibuprofen metabolism pathway.The degradation characteristic for I2,I4 and I14 were confirmed by solid medium.Though all the strains could degrade the selected homologues of ibuprofen,I2 was better than the other two strains on the degradation ability.The fuction genes in ibuprofen pathway were accurately positioned in genome sequence after the genomic analysis,which were verified by enzymic methods,gene knockout and so on.The gene clusters and predicted coding genes of ibuprofen degradation pathway were generally identified.The main results of this thesis were as followed.(1)All of these strains could use ibuprofen and homologues as the carbon source.But the tolerance of various substrates was different.I2 was better than the other two strains on the ability of degradation.Thus,I2 have the better practical for pollution abatement when compared with others.(2)The metabolic pathways of benzene series were found in I2 and I4 genome combining the genomic sequencing analysis.The annotation of catechol 1,2-dioxygenase pathway was intact while other pathways were defective.(3)The catechol 1,2-dioxygenase was ascertained as dominating enzyme of benzene series metabolic pathway in those three strains,after measured the specific activities of catechol 1,2-dioxygenase and catechol 2,3-dioxygenase.The orthogonal table with four factors and three levels was used to verify the optimum reaction condition including temperature,enzyme supplementation,time and p H.(4)The results of gene knockout testified that long-chain-fatty-acid COA ligase and catechol 1,2-dioxygenase were involved in ibuprofen pathway.The reliability of genomic analysis was segmentary.It was reasonable that I2 may degarade ibuprofen by different metabolic pathways considering the discrepancy of I2 and mutants on degrading capacity.