Effects of glycerol and glucose on the enhancement of biomass, lipid and soluble carbohydrate production by chlorella vulgaris in mixotrophic culture. Food Technology and Biotechnology

Biodiesel-derived glycerol is a promising substrate for mixotrophic cultivation of ole-aginous microalgae, which can also reduce the cost of microalgal biodiesel. The objective of this study is to investigate the potential of using glycerol and glucose as a complex car-bon substrate to produce microalgal biomass and biochemical components, such as photo-synthetic pigments, lipids, soluble carbohydrates and proteins by Chlorella vulgaris. The re-sults show that C. vulgaris can utilize glycerol as a sole carbon substrate, but its effect is inferior to that of the mixture of glycerol and glucose. The effect of glycerol and glucose could enhance the algal cell growth rate, biomass content and volumetric productivity, and overcome the lower biomass production on glycerol as the sole organic carbon source in mixotrophic culture medium. The utilization of complex organic carbon substrate can sti-mulate the biosynthesis of lipids and soluble carbohydrates as the raw materials for bio-diesel and bioethanol production, and reduce the anabolism of photosynthetic pigments and proteins. This study provides a promising niche for reducing the overall cost of bio-diesel and bioethanol production from microalgae as it investigates the by-products of algal biodiesel production and algal cell hydrolysis as possible raw materials (lipids and carbo-hydrates) and organic carbon substrates (soluble carbohydrates and glycerol) for mixo-trophic cultivation of microalgae. Key words: Chlorella vulgaris, glycerol, glucose, biomass production, biochemical compo-nents, mixotrophic cultivatio