Molecular diversity and biotechnological relevance of thermophilic actinobacteria

Extremophilic organisms have attracted significant attention of the research community during the recent past, not only due to their survival and growth at extreme conditions but also due to their huge potential in various fields of biotechnology. Among the various groups of extremophiles, thermophilic actinomycetes have been less explored due to the difficulties in their isolation and maintenance in pure culture. Therefore, it largely remains to explore their diversity, molecular phylogeny, adaptive features, and biocatalytic and other biotechnological potentials. In order to study actinomycetes, morphological features and morphogenesis, antibiotic sensitivity and resistance, biochemical characteristics, and certain key molecular features have been taken into account to get insight into the actinomycetes, in general. The molecular approaches include sequence homology of 16S rRNA genes, nucleic acid hybridization, G + C% ratio, protein profiling, RFLP, DGGE, TGGE and ARDRA for the assessment of diversity, taxonomic status, and molecular phylogeny. The thermophilic actinomycetes reflect quite appealing and unique applications in various fields of biotechnology, viz., production of thermostable enzymes, antibiotics, and hormones and their role in bioremediation processes of recalcitrant compounds. Further studies on the diversity and phylogeny would enhance understanding of the unexplored thermophilic actinobacteria that will promote their applications.