Strains of green microalgae as a promising feedstock for commercial fatty acid production

Abstract

Microalgae have received a lot of attention as a source of high-lipid feedstock to be used for the production of renewable energy in the form of biodiesel or other types of fuel, such as bioethanol, biobutanol and biogas. In addition, many microalgal strains produce significant amounts of essential fatty acids (such as ω3- and ω6-polyunsaturated fatty acids) which may have large importance in nutrition, cosmetics, and pharmacy. Recent investigations demonstrated that a group of freshwater green microalgae – desmids (Zygnematophyceae, Streptophyta) might have a significant potential for the commercial fatty acid production. Over 20 desmid strains were grown in standard cultivation conditions to assess their biomass and fatty acid content and productivities during the growth phases. The desmid strains investigated demonstrated the moderate values of biomass productivity (around 0.08 g CDW L-1 d-1), being the highest in Staurastrum boreale (0.14 g CDW L-1 d-1). The six desmid strains belonging to C. crenatum var. boldtianum, C. meneghinii, C. regnellii var. pseudoregnellii, C. leave, Staurastrum boreale and S. punctulatum had the exceedingly high total fatty acid contents (>200 mg g-1 CDW). The high amounts of linoleic and palmitic acids, and the low amount of oleic acid influenced the characteristics of desmid biodiesel, which partly satisfied the demanded standards for biodiesel. Hence, the improvement of the desmid biodiesel is recommended by the enhancement of the desmid growth conditions and/or by the partial hydrogenation. In addition, palmitic, linoleic and hexadecadienoic acids from desmid extracts can be utilized in cosmetics, pharmacy, medicine, and in industry.