Remediation of marine sediment contaminated with PAHs using bacterial inoculum, Novosphingobium pentaromativorans US-1

Abstract

Remediation of marine sediment contaminated with PAHs using bacterial inoculum, Novosphingobium pentaromativorans US-1Sang-Jin Kim1*, Kae Kyoung Kwon1, Hong-Bae Jung1, Hee-Soon Lee1 and Tian Yun21 Marine Biotechnology Research Center, Korea Ocean Research and Development Institute (KORDI), Ansan P. O. Box 29, 425-600, Korea (E-mail, s-jkim@kordi.re.kr)2 Institute of Applied and Environmental Microbiology, School of Life Science, Xiamen University, Xiamen, Fujian Province, China 361005Polycyclic aromatic hydrocarbons (PAHs) are well known as one of toxic environmental pollutants and can be easily accumulated in marine sediments. Due to hazardous potential on ecosystem including human-beings, removal of PAHs from sediment environments has been great concern. In this study, the conditions of fed-batch type bioslurry reactor were optimized and the effect of cyclodextrin on the degradation rate of PAHs was investigated. The PAHs degrading bacterial inoculum including Novosphingobium pentaromativorans US-1, a very active high molecular weight PAHs degrading bacterial strain, was also traced in the bioslurry reactor using T-RFLP method. The activity of electron transport system (ETSA) in the first reactor was increased from 5.1±0.1 ㎍-O2/㎖/hr after 1 day of treatment to 27.4±0.3 ㎍-O2/㎖/hr after 2-3 days. ETSA was highly maintained at 2-3 days even after the successive transfer of inoculum into the next bioreactor. The degradation rate of PAHs in the bioreactors, which was successively inoculated with 2-3 days interval, was ranged between 81 and 95 % regardless of inoculum size (20 % or 10 %). The degradation rate of PAHs could be maintained or even slightly increased under an optimal condition that treated sediment (as inoculum) was transferred from the first one to the next one after 2-3 days treatment and inoculum size was higher than 10%. However, no significant degradation could be detected and the number of bacteria in the bioreactor was reduced to