鞘氨醇单胞菌GY2B降解菲的特性及其对多种芳香有机物的代谢研究

Characterization of Biodegradation of Phenanthrene and Other Aromatic Substrates by Sphingomonas sp. GY2B

采用室内培养的方法,研究了一株鞘氨醇单胞菌GY2B以菲和其他芳香化合物为惟一碳源的降解特性。结果表明,菌株GY2B对10和60mg·L-1初始浓度的菲,分别在24和60h几乎降解完全,而对230mg·L-1初始浓度的菲,48h的降解率达到70%左右,此后菲浓度基本不再减少,到120h仍有大量的菲残留。计算表明,菲的初始浓度和菌株的比生长速率之间没有显著的相关性。进一步研究发现了高初始浓度的菲样品中会积累大量的中间产物1-羟基-2-萘酸。菌株GY2B降解水杨酸、1-羟基-2-萘酸和萘的过程中检测到2-羟基粘康酸半醛的吸收峰,该菌可能通过相同的途径降解这3种化合物。试验还证实菌株GY2B降解菲的过程也有2-羟基粘康酸半醛这种中间产物,更加明确了菌株GY2B先通过水杨酸途径,再经过邻苯二酚间位途径来降解菲。

The characterization of Sphingornonas sp. GY2B degrading phenanthrene and other substrates was described in this study. Phenanthrene was nearly degraded completely by strain GY2B at initial concentration of 10 and 60 mg·L^-1 after 24 and 60 hours inoculation, respectively. While only about 70% phenanthrene was degraded after 48 hours inoculation at initial concentration of 230mg·L^-1, and a lot of phenanthrene still remained in the medium after 120 hours inoculation. Further UV-Vis analysis showed a great deal 1-hydroxy-2-naphthoic acid was accumulated in the culture at highly initial concentration of phenanthrene. At the same time no significant correlation between initial phenanthrene concentration and microbial specific growth rate u was observed. In addition, 2-hydroxymuconic semial-dehyde as an intermediate in the degradation process of salicylic acid, 1-hydroxy-2-naphthoic acid, and naphthalene by strain GY2B, was found in the process of phenanthrene degradation through the UV-Vis analysis, which clearly suggested the degradation pathway of phenanthrene： under oxygenase of strain Sphingomonas sp. GY2B, phenanthrene was degraded via salicylate pathway and catechol meta-cleavage pathway to form 2-hydroxymuconic semial-dehyde.