Biodegradation of nonylphenol in mangrove sediment

This study investigated the biodegradation of nonylphenol (NP) in mangrove sediments collected at five sites along the Tanshui River in northern Taiwan. NP biodegradation rate constants (k₁) and half-lives (t_1/2) ranged from 0.039 to 0.139 day^-1 and 5.0 to 17.8 days, respectively. The biodegradation of NP was enhanced by the addition of yeast extract, hydrogen peroxide, brij 35, sodium chloride, or cellulose. However, NP biodegradation was inhibited by the addition of humic acid, heavy metals, or phthalic acid esters (PAEs). Of the microorganism strains isolated from the mangrove sediment, we found that strains A9, A10 and A13 (all identified as Bacillus sp.) expressed the best biodegrading ability. NP biodegradation rate constants (k₁) and half-lives (t_1/2) by the three strains ranged from 0.291 to 0.630 day^-1 and 1.1 to 2.4 days, respectively. The highest NP biodegradation rate was found in the sediment with the inoculation containing strains A9, A10 and A13, whereas the sediment without any inoculation had the lowest biodegradation rate.