NUCLEIC-ACID-BASED METHODS FOR MONITORING THE PERFORMANCE OF IN-SITU BIOREMEDIATION

Over the last decade, major advancements have occurred in the application of nucleic acid-based methods to detect and determine the levels of catabolic genes in environmental samples. Studies have focused on validating methods in microcosms, studying changes in the structure and expression of microbial communities in response to contaminants, and improving the sensitivity of the methods. Only in the last few years have these methods transitioned from development and validation to efforts to apply these methods for monitoring in situ bioremediation. Methods that analyse nucleic acids extracted from environmental samples are of value to bioremediation because they allow analysis independent of the artefacts that can arise from laboratory biodegradative potential assays and laboratory culture-based enumerations and from the inability to culture a large proportion of the micro-organisms in the environment. In theory, these methods enable a more comprehensive perspective, and a more defensible interpretation, of the microbial community response to intrinsic and engineered bioremediation processes. Results from the first studies applying nucleic-acid-based methods to intrinsic or engineered bioremediation indicate that these methods have both potential and limitations. The rapidly increasing number of cloned and sequenced catabolic genes, methodological advancements such as the ability to track specific micro-organisms without prior sequence data, and the potential use of bioaugmentation in the field suggest that the utility of these methods for in situ bioremediation will increase in the coming years.