Uncovering the biological roles of recently discovered carbohydrate-active enzymes in green microalgae.

Microalgae have colonized every habitat on Earth, and are paramount in fueling the global ocean biological carbon pump. Moreover, microalgal biotechnology is of prime importance for developing a sustainable economy. Algae result from a complex evolutionary history that shaped their metabolic networks, and many aspects of their biology remain understudied. Lytic polysaccharide monooxygenases (LPMOs) are copper-containing enzymes involved in the metabolism of polysaccharides in bacteria, fungi, and insects, and have only recently been discovered in algae (Sabbadin et al. Nat. Com. 2018). No biological roles have been associated with these enzymes in these organisms yet. In this context, the current project will investigate the potential roles of three candidate LPMOs identified in Chlamydomonas reinhardtii, a well-established genetic and genomic model to study different aspects of algal biology. Preliminary analysis has suggested roles in different biological processes for these three enzymes, and hypotheses will be tested using a combination of reverse genetics, cell biology, biochemical, molecular, and in silico approaches. Results obtained will advance understanding on fundamental processes such as algal primary metabolism and environmental adaptation. It will help to better understand the ecological success of algae, and provide support for their uses in biotechnological applications.