(204c) Continuous Cultivation of Microalga Nannochloropsis Oculata to Extract and Characterize Polar Lipids for Cosmetic Applications

Global demand for natural and renewable products have skyrocketed recently, leading to many new possibilities and markets. These new markets have shifted the trend towards the production of sustainable products. Algae, specifically microalgae, that are promising sources of natural ingredients owing to their cell mass containing polysaccharides, proteins, lipids, pigments, and vitamins have been the benign raw materials. Particularly the interest on phospholipids, a subgroup of polar lipids, has been on the rise due to the fact that they are the appropriate candidates to the pharmaceutical and cosmetics industry for various applications such as emulsifiers, liposome formers, solubilizers, wetting agents, and bioactive compounds. Liposomes made out of pure phospholipids are the major contributers to the cosmeceuticals, which can contain up to 20% (w/v) phospholipids, being a part of a $62 billion/year industry in US alone. Besides, cosmeceuticals account for over 12% of the cosmetics market.

Phospholipids are currently extracted from food sources; however, this practice raises sustainability issues because of the competition with food. Microalgae can serve as a source of phospholipids on a more sustainable basis. In order to advance the status of microalgae bioproducts for cosmetics applications, the marine microalga Nannochloropsis oculata (N. oculata) was cultivated in a vertical flat panel photobioreactor (VFPPBR) in batch and continuous mode. Batch cultivation of N. oculata was performed to optimize the growth parameters, estimate its maximum specific growth rate (µ_max), and determine its phospholipid productivity. Because the total lipid productivity is essential to increase the phospholipid productivity, optimization of volumetric microalgal biomass productivity in turn boosted up the overall lipid productivity. The measured µ_max was utilized in selecting the dilution rate for designing and operating a VFPPBR-based continuous cultivation of N. oculata that was deemed to be more scalable and productive operation from a commercialization aspect. Cell harvesting via centrifugation was followed by solvent/pressurized solvent extraction to capture and isolate the microalgal polar lipids, specifically phospholipids. The experimental findings from continuous cultivation of N. oculata species, the robustness of the strain, and its polar lipid productivity, photobioreactor design, performance of the species in batch and continuous mode of operation, and green pathways for downstream processing to isolate, concentrate and fractionate microalgal phospholipids were analyzed and discussed.