Biodegradation Of Bromoamine Acid By Sphingomonas Xenophaga And DNA Fingerprint Analysis Of Augmented System

The purpose of this dissertation is to investigate the characteristics of a newly isolated Sphingomonas xenophaga QYY with the ability to degrade bromoamine acid (BAA). The physio-biochemical characterization and 16S rDNA molecular identification were carried out. The characteristics of strain QYY growth and BAA degradation were also investigated and the possible metabolic pathway of BAA degradation by strain QYY was presumed. Meanwhile, bioaugmentation of BAA degradation with strain QYY as augmented inoculums was studied, and the dynamic and structural changes of microbial community in augmented system were revealved by modem molecular ecological techniques.Strain QYY is an efficient BAA-degrading strain. It was identified as Sphingomonas xenophaga belonging to Proteobacteria a subclass based on morphological and physio-biochemical characteristics and 16S rDNA sequence analysis. Strain QYY is deposited as a patent strain in China General Microorganism Culture Center with the accession number CGMCC 1172. The 16S rDNA sequence of strain QYY shared high similarity (99%) with that of type strain DSM6383. The 16S rDNA sequence of strain QYY was submitted to GenBank with the number AY611716. A novel non-function wide plasmid (pSx-QYY) about 5683bp was isolated from strain QYY by the mega plasmid extraction strategy. The plasmid contains four opening reading frames (ORFs), of which contains gene encoding replication protein of E. coli. The sequence of pSx-QYY was submitted to GenBank with the accession number AY787146.The characteristics of strain QYY growth and BAA degradation were investigated with the purpose of building a foundation for bioaugmentation experiments. Strain QYY is resistant to streptomycin and sensitive to other antibiotics. The optimal conditions for both growth and degradation process are as follows: pH=7.0, temperature 30℃, shaking speed 150r/min and inoculation amount 8%. Strain QYY can tolerate up to 1000mg/L BAA. The optimal degradation conditions of resting cells were also obtained as follows: pH=8.5, temperature 30℃, shaking speed 150r/min. The entrapped immobilization method of alginate sodium was adopted. The optimal degradation conditions for immobilized cells are obtained as follows: shaking speed 150r/min, temperature 30℃, pH=4.0-8.0.The metabolic pathway of BAA degradation by strain QYY was investigated by advanced analytical instruments such as UV-Vis, Ion Chromatogram, HPLC-MASS, H-NMR, etc. The final products were identified and the possible metabolic pathway was presumed. During the...