Microalgal carbohydrates and proteins: Synthesis, extraction, applications, and challenges

Abstract

Microalgae are a promising feedstock for renewable energy, nutraceuticals, pharmaceuticals, and other high-value industrial products. The major components of algal biomass are carbohydrates, lipids, and proteins, whose concentration depends upon cultivation conditions, composition of growth media, light intensity/duration, and CO2 supplies. Microalgae can also be exploited as an alternative “protein crop” based on amino-acid composition, protein quality, and digestibility. Algal carbohydrates are mainly in the form of starch and cellulose, which can be used to produce bioethanol and degradable bioplastics. Although use of algal biomass for various products looks attractive, yet its commercial demonstration is hindered by the slow growth, low product yields, unavailability of high-throughput extraction procedures, and the product-refining processes. This book chapter comprehends the cultivation conditions to enhance the algal protein and carbohydrate content along with extraction techniques, and associated challenges for the recovery, separation, and characterization of these metabolites. Likewise, the potential applications of the microalgae-based carbohydrates and proteins in energy, food, pharmaceutical, and cosmetic industries along with future opportunities are also discussed to devise a roadmap for designing robust algal biorefineries.