(10d) Microalgae Fractionation and Recovery of Native Components through Application of Low-Cost Enzymes

Liquid fuels from microalgae biomass has become unattractive recently due to the fall in prices of petroleum and natural gas. However, interest in microalgae biomass as feedstock for bioproducts (nylons, succinic acid) has been on the rise. This is as a result of the economic and environmental benefits associated with the processing of these higher value products using microalgae biomass. Microalgae biomass consists mainly of carbohydrate, protein and lipids. When efficiently extracted, the lipids could be used as precursors for nylon, the carbohydrate for the production of succinic acid and the protein rich residue as feed for animals. Enzymatic hydrolysis is a relatively effective means for the extraction of the various components of microalgae. This method requires mild reaction condition (T~55 ^oC), produces fewer side- and by-products and eliminates the use of strong acids (no corrosion challenges). This work focuses on the enzymatic digestion of microalgae biomass using low-cost and industrial-scale α-amylase, glucoamylase, protease and their combinations. Using these enzymes nearly all the storage carbohydrate was extracted in the form of monomeric sugars (glucose) and no loss in the quality of the lipid and protein components. This benign digestion process also allows the recovery of high value products (e.g. pigments) without chemical modification or disintegration. The details of our work on the optimization of the process, enzymes recovery and reuse will be presented.