Genetic engineering strategies for environmental applications.

Environmental applications of genetically engineered microorganisms are currently hampered not only by legal regulations restricting their release, but also by the frequent dearth of adequate genetic tools for their construction in the laboratory. Recent approaches to strain development include the use of non-antibiotic markers as selection determinants, the use of transposon-vectors for the permanent acquisition of recombinant genes, and the utilization of expression devices based on promoters from promiscuous plasmids and biodegradative pathway genes.