成晶节杆菌NT16和共生芽孢杆菌NG16联合代谢1-萘酚的特性

Characteristics of the co-metabolism of 1-naphthol by Arthrobacter crystallopoietes NT16 and symbiotic Bacillus NG16

1-萘酚是多环芳烃降解过程中极易积累的典型含氧多环芳烃,其难降解、毒性大,直接影响多环芳烃污染环境的修复效果.为探究微生物联合代谢1-萘酚的特性,以前期从含氧多环芳烃污染土壤中分离出的两种共生菌株——成晶节杆菌NT16和芽孢杆菌NG16为受试菌株,结合HPLC、TOC、GC-MS等测定方法进行降解特性的测定.结果表明,NT16菌和NG16菌均能以1-萘酚为唯一碳源和能源生长,两种菌株联合代谢比NT16菌、NG16菌单独降解1-萘酚的生长量分别高2.758×10~9 cfu·mL^(-1)和1.4×10~9 cfu·mL^(-1),对1-萘酚的降解率可提高20%,使体系中TOC值加速降低.NT16菌和NG16菌联合代谢1-萘酚可按照两个途径进行,其一,1-萘酚羟化后开环,进入邻苯二甲酸代谢途径.NT16菌更易进入该途径,而NG16菌则不易通过该途径降解1-萘酚;其二,1-萘酚羟化后开环,进入苯丙酸代谢途径.NG16菌迅速将1-萘酚降解为对羟基苯乙酸,其在降解体系中积累,NT16菌无法高效降解1-萘酚却能够降解对羟基苯乙酸至较短烷基链的小分子化合物.该研究结果将为含氧多环芳烃污染环境实际修复中微生物群落协同作用降解污染物奠定基础.

1-naphthol is a typical oxygen-containing polycyclic aromatic hydrocarbon(PAH) that is easily accumulated during the degradation of PAHs, which are highly toxic, difficult to be degraded and directly affect the remediation of polluted environment. In order to explore the characteristics of microbial co-metabolism of 1-naphthol, two symbiotic strains isolated from oxygen-containing PAH-contaminated soils, degradation characteristics of Arthrobacter crystallopoietes NT16 and Bacillus NG16, were determined by HPLC, TOC, GC-MS and other methods.We discovered that both NT16 and NG16 could use 1-naphthol as the sole carbon and energy source. The biomass of the co-culture of the two strains with 1-naphthol was 2.758×10^9 cfu·mL^-1 and 1.4×10^9 cfu·mL^-1 respectively higher than any of NT16 or NG16 alone. The degradation rate of 1-naphthol could increase by 20% and TOC could be removed more quickly. The co-culture of NT16 and NG16 could metabolize 1-naphthol in two pathways. Firstly, 1-naphthol is hydroxylased and enters the phthalate metabolic pathway. NT16 are more likely to enter phthalate pathway, NG16 are not easy to degrade 1-naphthol through this pathway. Secondly, 1-naphthol is hydroxylated and then enter the phenylpropionic acid metabolic pathway. NG16 rapidly degrades 1-naphthol to 4-hydroxyphenylacetic acid, which accumulated in the degradation system. NT16 could not degrade 1-naphthol efficiently but degrade 4-hydroxyphenylacetic acid to small molecule compounds of short alkyl chain.The results of this study will lay the foundation for the synergistic action of microbial communities to degrade pollutants in the actual restoration of oxygen-containing PAH.