Characterization of strains of Chlorella from Abakaliki, Nigeria, for the production of high-value products under variable temperatures

Abstract

The successes made in the production of algal high-value products in the last decades are threatened by the continuous rise in global temperature to which most strains are not fully adapted. The choice of strains adapted to high temperatures from novel locations with excellent potential to produce high concentrations of biomolecules such as lipids, carbohydrates, pigments, and antioxidants is extremely important and requires continuous exploration. In the present study, strains Chlorella lewinii KU220 JNI1, Chlorella sp. NEIST JNI3, Chlorella lewinii KU217 JNI6, and Chlorella sp. NC JNI8 were characterized for the quantity and quality of lipids and fatty acids, pigments, carbohydrates, and proteins at 20, 25, and 30°C. The highest biomass (cell densities and ash-free dry weight), chlorophylls, and carotenoids production occurred at 25 and 30°C. Regardless of the growth temperature, total lipids, total carbohydrates, and total protein levels ranged from 12.96 to 51.11% of ash-free dry weight. Palmitic acid (C16:0) and stearic acid (18:0) were the predominant fatty acids in the strains irrespective of temperature conditions. With such high levels of fatty acid saturation and biodiesel characteristics, the lipids were best suited for bioenergy purposes. The excellent general performance of the strains under the different temperature treatments means they are adapted for bioenergy and food applications in areas with variable and rising temperatures.