Characterization and phylogenetic analysis of a phenol and halogenated aromatic compound degrading microbial consortium

Industrial and agricultural toxins such as chlorinated and hydroxylated aromatic compounds cause significant environmental pollution and health problems, due to their toxicity and overall recalcitrance to microbial degradation. Utilizing the metabolic processes of bacteria to degrade these toxins at a contaminated site is the ultimate goal of microbial bioremediation. To realize this goal, one must understand the physiological response of biodegrading bacteria to commonly encountered environmental toxins. Currently, with the exception of the well studied and nutritionally versatile genus Pseudomonas , little is known regarding the identities, phylogenetic relatedness or the physiology of most bacteria that have potential as bioremediators of environmental pollutants. Described in this study are bioprocessor isolated bacteria of diverse phylogeny and versatile metabolic capabilities, such as the ability to utilize phenol and chlorinated aromatic compounds as sole carbon sources. The physiology and 16s rDNA based phylogeny of novel isolates from three separate groups of eubacteria will be discussed. Phenol degrading beta-Proteobacteria of the family Alcaligenaceae, phenol and chlorinated benzene degrading Actinobacteria of the suborder Corynebacterineae, as well as chlorinated and fluorinated benzene degrading alpha-Proteobacteria belonging to the family Brucellaceae will be described. A polyphasic method including biochemical profiling, chemotaxonomy, and 16s rDNA sequence analysis was employed in the identification and characterization of these unique bacteria. In addition, the effect of nitrate stimulation and subsequent aerobic denitrification on the aromatic toxin degradation kinetics of these novel isolates and previously described toxin degrading bacteria of the genera Pseudomonas and Rhodococcus was investigated.