Isolation and Identification of Marine Actinobacteria

Actinobacteria are some of the most productive and biotechnologically valuable bacterial phyla with the ability to produce bioactive compounds, industrial enzymes, and metabolites with agricultural and environmental applications. Actinobacteria were the key players in ecosystem processes as degraders of bulky organic substrates, while at the same time being humanity’s main source of antibiotics and other therapeutic leads. Traditional cultivation methods access only 1–5% of actinobacterial diversity, and this shortfall has been referred to as the “great plate count anomaly.” This chapter is a comprehensive overview of actinobacterial isolation techniques and provides an interface between historic methods and state-of-the-art techniques intended to realize the untapped potential hidden amongst non-culturable diversity. Ecological sources ranging from terrestrial, freshwater, and saltwater environments to extremophilic environments are surveyed with a focus on how adaptations to habitats result in biosynthetic performance. The approach to methods varies from selective and pretreatment techniques to state-of-the-art techniques, like ecological mimicry, microfluidics, and in situ cultivation and co-culture enrichment techniques. Molecular tools for identification, combining phylogenomics with morphological information, are outlined as powerful templates to characterize new taxa. The chapter concludes with future research trends like multi-omics techniques, AI-augmented cultivation techniques, and synthetic biology methods, while considering global bioprospecting’s ethics and regulation ramifications. The present chapter serves as a scholar’s reference and a hands-on guide to actinobacterial research advancement and biotechnology implementation using exhaustive protocols, case studies, and troubleshooting manuals.