Biosynthesis of Chlorophyll and Bilins in Algae

Abstract

Chlorophylls and bilins are tetrapyrrole pigments that are synthesized from the universal five carbon precursor aminolevulinic acid (ALA). All algae and cyanobacteria make chlorophylls, and they also appear to have the ability to make bilins. The primary use of chlorophylls and bilins are as light harvesting pigments in these organisms. Chlorophylls are present in the light harvesting complexes and reaction centres while bilins are pigment components of phycobilisomes. Phycobilisomes appear to be restricted to the cyanobacteria, glaucophytes, red algae and the secondary endosymbiotic ancestors of the red algae such as the cryptophytes. This chapter explores the diversity and biosynthesis of both bilins and chlorophylls which are used in light harvesting for photosynthesis in algae and cyanobacteria.