DEGRADATION OF NAPHTHALENE, ANTHRACENE, PHENANTHRENE AND PYRENE BY AEROBIC MICROORGANISMS

Microbial degradation of polycyclic aromatic hydrocarbons (PAHs) was investigated by enrichment culture with mangrove sediments obtained from the Hong Kong Nature Reserve. The effects of initial substrate concentration and single- or multi-substrate systems on the growth of bacteria in the enrichment culture were measured. The degradation ratios were higher at such initial concentrations of PAHs as naphthalene 64—256 mg·L~(-1), anthracene 214—428 μg·L~(-1), phenanthrene 4.8—9.6 mg·L~(-1), and pyrene 520—2080 μg·L~(-1) than at other initial concentrations. Multi-substrate systems were more congenial to the growth of bacteria than single-substrate systems. In our study, one strain Aeromonas caviae WⅡ chosen from the sixty-one PAHs-degraders isolated from the enrichment culture was capable of degrading all four kinds of PAHs effectively, and another strain Aeromonas punctata TⅡ of degrading naphthalene, anthracene and pyrene effectively. Strain A. punctata TⅡ could not degrade phenanthrene, but was able to decrease its volatile rate in the culture medium.