Applications of microalgal and cyanobacterial biomass on a way to safe, cleaner and a sustainable environment

Algae (especially microalgae and cyanobacteria) are potentially diverse, ubiquitous, and dominant group of photosynthetic organisms in nature. The dominance and diversity of algae are commonly observed in small puddles, streams, river, to oceans and even in extreme habitats like cold springs to hot deserts, which makes them a prominent organism for various applications. The past decade has evidenced microalgal research in bioenergy production and other vital biomolecules with wide industrial applications. Further, the easy availability of microalgae and cyanobacteria makes them a suitable candidate for various biotechnological applications like food, feed, fodder, and fuel. Algae are grouped under the third generation biofuel feedstock offering numerous environmental benefits viz., efficient land usage, CO2 sequestration and utilization and most importantly resolving the food vs fuel feud. With this perspective, this review article aims to unravel the conventional and novel applications of microalgal and cyanobacterial biomass in various enterprises and also the recent trends in their exploitation. To understand the overall potential of microalgae, at inception, this review article has articulated a detailed account of the applicability of various algal biomasses for different biofuels such as bioethanol, biodiesel, and biohydrogen. As an environmental benefit, bioremediation of wastewater or nutrient removal from municipal and industrial sources, and pesticide removal using several microalgal strains has been critically appraised and presented comprehensively. Also, the enormous biodiversity and difference in the biochemical composition of microalgae make them stand as a promising source for biologically active compounds with high commercial value. In addition to energy products from algae, converting the biomasses into various industrially important co-products or high value products is an economically sound approach. At this juncture, extraction of secondary metabolites, carotenoids, phycobiliproteins, phytosterols and phenolic compounds from numerous microalgae and cyanobacteria has been discussed in detail. Overall, the present review gives a detailed account of the biofuel production from algae, bioproducts extraction, environmental applications of microalgae, and cyanobacteria for bioremediation. (C) 2019 Elsevier Ltd. All rights reserved.