Environmental biodegradation of halophenols by activated sludge from two different sewage treatment plants

Abstract

Halophenols make a group of aromatic compounds that are resistible to biodegradation by environmental microorganisms. In this study, the biodegradation of 4-bromo-, 4-chloro- and 4-fluorophenols was studied with two types of activated sludges (from a small rural plant and from a bigger municipal plant) as an inoculum. Because of their wide use, surfactants are present in the wastewater and inhibitors enhance the biodegradation of different pollutants; the influence of natural surfactants on halophenols' biodegradation was also tested. Both types of activated sludge contained bacterial strains which were active in the halophenols' biodegradation process. The coexistence of surfactants and halophenols in the wastewater does not prevent microorganisms from effective halophenols' biodegradation. Moreover, surfactants can enhance the effectiveness of halophenols' removal from the environment. Different cell surface modifications of two isolated bacterial strains were observed in the same system of halophenols with or without surfactants. Halophenols and surfactants may also induce changes in bacteria cell surface properties.

Environmental Aspects of the Use of Hedera helix Extract in Bioremediation Process

“…Hydrocarbon-degrading bacteria, Raoultella ornitinolytica M03 and Acinetobacter calcoaceticus M1B, isolated from long-term, hydrocarbon-contaminated soil and obtained by enrichment in a mineral medium (pH 7.2) with diesel oil as the sole carbon source [22], were used in the experiments. The bacteria were identified genetically, and their nucleotide sequences are available in GenBank under the following accession numbers: KX.667739.1 (M03) and KU.563543.1 (M1B).…”