Pentachlorophenol-contaminated soil bioremediation: survival and efficacy of monoculture inoculants and enrichment of indigenous catabolic populations

Survival and efficacy of monoculture inoculants of Flavobaderium sp. and Rhodococcus chlorophenolicus to bioremediate PCP-contaminated soil were examined under sterile and non-sterile conditions. Both species effected ≥ 40% catabolism in four weeks although inoculant survival was significantly higher with R. chlorophenolicus. Supplements of bark chips or distillery waste with the inoculant did not, initially, promote bioremediation. PCP addition per se effected enrichment of indigenous catabolic populations and this was promoted by the presence of wood chips. Both aerobic and anaerobic enrichments were successful and PCP mineralization under both conditions was recorded. Under anoxic conditions, dehalogenation of o-substituents was dominant although some meta-chlorines were removed. Provisional evidence of two separate isomer-specific dehalogen-ating populations was obtained.