title: Biodegradation of phenolic compounds by sulfate-reducing bacteria from contaminated sediments.
abstract: The biodegradation of phenolic compounds under sulfate-reducing conditions was studied in sediments from northern Indiana. Phenol, p-cresol and 4-chlorophenol were selected as test substrates and added to sediment suspensions from four sites at an initial concentration of 10 mg/liter. Degradative abilities of the sediment microorganisms from the four sites could be related to previous exposure to phenolic pollution. Time to onset of biodegradation of p-cresol and phenol in sediment suspensions from a nonindustrialized site was approximately 70 and 100 days, respectively, in unacclimated cultures. In sediment slurries from three sites with a history of wastewater discharges containing phenolics, time to onset of biodegradation was 50-70 days for p-cresol and 50-70 days for phenol in unacclimated cultures. In acclimated cultures from all four sites, the length of the lag phase was reduced to 14-35 days for p-cresol and 25-60 days for phenol. Length of the biodegradative phase varied from 25 to 40 days for phenol and 10 to 50 days for p-cresol and was not markedly affected by acclimation. Substrate mineralization by sulfate-reducing bacteria was confirmed with radiotracer techniques using an acclimated sediment culture from one site. Addition of molybdate, a specific inhibitor of sulfate reduction, and bacterial cell inactivation inhibited sulfate reduction and substrate utilization. None of the sites exhibited the ability to degrade 4-chlorophenol, nor were acclimated phenol and p-cresol degrading cultures from a particular site able to cometabolize 4-chlorophenol.
authors.affiliation: Department of Biology, Indiana University-Purdue University at Fort Wayne, 46805-1499, Fort Wayne, IN, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Mort
authors.forename: D
authors.initials: D
authors.lastname: Dean-Ross