Different bacterial groups for biodegradation of three- and four-ring PAHs isolated from a Hong Kong mangrove sediment.
Mangrove sediments have been found to degrade three- to four-ring PAHs extensively. In the present study, 11 strains from 4 genera Mycobacterium (3 strains), Sphingomonas (5), Terrabacter (2) and Rhodococcus (1) were isolated from a single surface sediment sample of a Hong Kong mangrove swamp, among which the Terrabacter strains were isolated to grow with fluoranthene for the first time. Although all four genera could degrade three- and four-ring PAHs, their in situ activities in natural sediment slurry were found to be different. A cultivable method showed that Sphingomonas strains grew rapidly under the induction of three-ring, but not four-ring PAHs, while only Mycobacterium degrading strains dominated in the four-ring PAHs spiked slurry. Culture-independent method using a reverse transcriptional PCR showed expressions of nahAc-like (mainly found in Gram-negative bacteria) and nidA-like (in Gram-positive bacteria) dioxygenase genes parallel with the degradation of three- and four-ring PAHs, respectively. The present study suggested that surface mangrove sediments harbored diverse PAH-degrading bacteria, which showed different importance for biodegradation of three- and four-ring PAHs in the sediment.
Zhou
Hong Wei
HW
Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong SAR, China.
Luan
Tian Gang
TG
Zou
Fei
F
Tam
Nora Fung Yee
NF
D019015:Geologic Sediments / Q000737:chemistry*; D006723:Hong Kong; D011083:Polycyclic Compounds / Q000378:metabolism*; D014871:Water Microbiology; D014874:Water Pollutants, Chemical / Q000378:metabolism*
D011083:Polycyclic Compounds; D014874:Water Pollutants, Chemical