Chapter 2 - Biodiversity and biogeography of microalgae with food and feed potential

Abstract

Microalgae, including cyanobacteria, are a group of diverse microorganisms that exhibit oxygenic mode of photosynthesis as a common characteristic. Due to conceptual and technological/analytical limitations, their exact number is unknown and requires inputs from systematics, dispersal analyses, and biogeography. The group occupies all life-supporting habitats, which may be widely separated and present in disconnected geographies. They show both cosmopolitan and endemic distribution and are often subject to the technology used for their estimation. The precise mechanism of their dispersal is poorly understood. The use of molecular tools and resulting data has led to the refinement in the taxon boundaries and, thereupon, species delimitation, which is profoundly reshaping our understanding of their diversity, distribution, and difficulties associated with their accurate assessment. Furthermore, the sampling procedure for diversity estimation is yet to be standardized. The fluid nature of species characterization further complicates the task of enumeration of biodiversity indices. Statistical tools play a vital role in biodiversity estimation but are less used in studying microalgal diversity. Apart from highly acclaimed ecological roles, human use of microalgae for food, feed, medicine, fertilizers, and a slew of other uses is known since long (prior to 2700BCE). In recent times, attempts for using microalgae for nutraceuticals, biofuels, and therapeutic drug production have increased. In the present chapter, we have discussed the recent estimates of microalgal diversity, their biogeography, and the associated conceptual and technological constraints for their potential use as a food and feed source.