Algae Oil and Biomass
The following is excerpted from the research and writings of Dr. Mark Edwards, one of the world’s foremost authorities on algae.
Algal-oils are extremely high in unsaturated fatty acids and various algal-species provide linoleic acid, an unsaturated omega-6 fatty acid and finds uses for soaps, emulsifiers, quick-drying oils and a wide variety of beauty aids. The moisture retention properties are valued skin remedies used for smoothing and moisturizing, as an anti-inflammatory and for acne reduction. Arachidonic acid, an omega-6 fatty acid also found in peanut oil. This product moderates inflammation and plays an important role in the operation of the central nervous system.
Eicospentaenoic acid is an omega-3 fatty acid and gives the same benefits as fish oil. Research suggests that EPA may affect depression and moderate suicidal behavior Docosahexaenoic acid, an omega-3 fatty acid generally found in fish oil and is the most abundant fatty acid found in the brain and retina. DHA deficiency is associated with cognitive decline and increase neural cell death. DHA is depleted in the cerebral cortex of severely depressed patients. Gamma-linoleic acid, an omega-6 fatty acid found in vegetable oil and was first extracted from the evening primrose. It is sold as a dietary supplement for treating problems with inflammation and auto-immune diseases. Research is ongoing on its therapeutic value for cancer to suppress tumor growth and metastasis.
Many species of algae are tolerant of wide variations in growing conditions. Some species are nearly blind to geography. Algal production typically starts with the classic entrepreneurial question: What is the highest value product(s) that can be produced? For decades that question has been answered based on local conditions where producers either harvested natural stands, enhanced natural settings or produced Spirulina in open ponds. Closed systems offer the advantage that high nutrient water may be recycled through the system. This practice significantly lowers the cost of added nutrients. It also minimizes water loss to evaporation. Harvest ‘may occur’ daily by filtering, centrifuge or flocculation. The cells suspended in the broth are separated from the water and residual nutrients are recycled to biomass production. Algal oil is extracted from the recovered biomass converted to biodiesel.
Some of the non-oil biomass may be used as animal feed, fertilizer and for other coproducts. Some systems use solar panels with photovoltaic cells to convert solar energy directly to electricity which is either used directly, used to warm production water or store in batteries. After the oil component is used for biofuel, the remaining high protein biomass may be demoistured and stored in a convenient form such as a cake which does not require refrigeration and has about a two year shelf life. The algal cake may be separated into various food, food ingredients, fodder, fertilizer, fine medicines or other components. The harvested biomass is extremely malleable in the sense that it can be stored in the same form as corn, wheat, rice or soy products. These include protein-rich milk, soft mash of any size, shape or texture, tortilla, cracker or flour. The biomass may be made into texturized vegetable protein with added fiber or extruded to make additives for meats that improve moisture retention and increase protein while lowering fats. Processing can match the form of nearly any food such as peanuts, pasta, pesto or protein bars.
Fortunately, years of food processing for land-based plants that have an unappealing natural taste such as soybeans make it easy to add flavors, textures (fibers) and aromas. The desired product outcome drives strain selection, growth parameters and processing. Better algal strains through screening natural varieties, hybridization and bio-engineering may motivate some growing systems to be dedicated to one or both foods or fuels.