Isolation and selection of growth medium for freshwater microalgae Asterarcys quadricellulare for maximum biomass production.

The use of microalgae biomass as a suitable alternative feedstock for biofuel production has been promoted in the field of green biotechnology. In this present study, the microalgae were isolated from freshwater samples. The predominant strain was screened from the samples and grown in four different growth media, including modified Bold's Basal Medium (BBM), modified CFTRI medium, BG11 medium and CHU medium, to find the suitable growth medium to enrich biomass production. In total three microalgae colonies were identified based on their colony morphology microscopically by using a light microscope. The predominant strain was confirmed as Asterarcys quadricellulare using 18S rRNA sequencing. The growth of microalgae was investigated based on parameters like dry weight, pigment composition such as chlorophyll a, chlorophyll b, carotenoid and lipid content in the microalgae. Among the four different media, modified BBM medium showed maximum dry weight (1.44 ± 0.015 g/L), chlorophyll a (23.07 ± 0.049 mg/L), chlorophyll b (16.76 ± 0.010 mg/L), carotenoid (8.92 ± 0.031 mg/L) and lipid content (375 ± 0.020 mg/L) on the 25th day of culture. The gas chromatography mass spectrometry (GC/MS) analysis showed the presence of major fatty acids stearic acid, palmitic acid and oleyl alcohol in the microalgae. Therefore the high lipid content and fatty acid profiles of Asterarcys quadricellulare are becoming a promising suitable strain for biofuel production with modified BBM medium.