Lipid extracted algae as a source for protein and reduced sugar: A step closer to the biorefinery

• Lipid extracted algae (LEA) was used as a source for protein and reduced sugars.
• Comparable yields of these products were obtained from total algae and LEA.
• Microwave assisted extraction from oven dried samples provided highest lipid yield.
• Effective cell disruption for lipid extraction increased loss of other products.
• Maximizing the yields of all products requires proper process selection.

The objective of this study was to investigate the feasibility of using lipid extracted algae (LEA) as a source for protein and reduced sugar, and the effects of various procedural treatments on their yields. LEA provided comparable yields of protein and reduced sugars to those from total algae. Oven drying provided highest yields of all products followed by freeze drying, while sun drying significantly lowered their yields. Effective cell disruption by microwave and autoclave increased the lipid yields from algae, but resulted in increased loss of other compounds with lipid extracting solvents lowering their yields during sequential extraction. Relatively inefficient cell disruption by ultrasonication and osmotic shock lowered the amount of cell protein lost to the lipid extracting solvents. These results highlight the complexity of concurrent extraction of all value added products from algae, and the need for proper selection of the processes to achieve the objectives of integrated biorefinery.