Microbial polyhydroxyalkanoates from extreme niches: Bioprospection status, opportunities and challenges

Extreme niches are offered with unusual physiochemical conditions that impose stress to the life-forms including microbial communities. Microbes have evolved unique physiology and genetics to interact dynamically with extreme environments for their adaptation and survival. Amongst the several adaptive features of microbes in stressed conditions, polyhydroxyalkanoates synthesis is a crucial strategy of many bacteria and archaea to reserve carbon and energy inside the cell. Apart from the relevance of PHA to microbial world, these intracellular polyesters are seen as essential biological macromolecules for the bio-material industry owing to their plastic-like properties, biodegradable and eco-friendly nature. Recently, much attention has been attracted by the microbes of extreme habitats for a new source of industrially suited PHA producers and novel PHA with unique properties. Therefore, the current review is focused on the critical evaluation of microbes from extreme niches for PHA production and opportunities for the development of commercially feasible PHA bioprocess.