Screening of Microalgae for Lipids and Their Extraction and Characterization

Abstract

Nine microalgae (Nostoc muscorum, Spirulina.sp, Oscillatoria R2, Chlorella Cp4, Chlorella R5, Nannochloropsis oculata, Botrycoccus braunii, Scendesmus armatus, Chlamydomonas moewsii) were screened for containing lipid content. Overall it was observed showed that all the algal cultures showed increase in biomass and lipid content with increase in time interval of 7 days respectively. Nannochloropsis oculata showed highest lipid content from 0.32 mg/ml on 7th day to 0.42 mg/ml on 28th day with increase in wet biomass from 0.26 mg/ml on 7th day to 0.46 mg/ml on 28th day and increase of dry biomass from 0.04 mg/ml on 7th day to 0.13 mg/ml on 28th day in lab conditions respectively. Variation was found when Nannochloropsis oculata was grown in open condition, where it showed increase in lipid content from 0.32 mg/ml on 7th day to 0.42 mg/ml on 28th day with the increase in wet biomass from 0.26 mg/ml on 7th day to 0.46 mg/ml on 28th day and dry biomass from 0.04 mg/ml on 7th day to 0.08 mg/ml on 28thday respectively. Chlorophyll content was found to be highest in Spirulina.sp (2.6 µg/ml). Increase in lipid content by Spirulina.sp and Nostoc muscorum in open tubs as well as lab conditions was slow. Microalgal were disrupted by homogenization and ultrasonication to release lipids . Maximum lipids were released when cells were homogenized and further ultrasonicated. Four microalgae algae (Nannochloropsis oculata, Nostoc muscorum, Spirulina.sp, Oscilltoria R2) that were found to contain high lipid content and were selected for lipid extraction and characterization by HPLC. HPLC characterization indicated that in lipid of all the four microalgae contained fatty acid fraction similar to that are present in olive oil. In situ tranesterification was used for making biodiesel. Nannochloropsis oculata appeared to be potential source for biodiesel production followed by Oscillatoria R2 as both contains high lipid content and grows rapidly in lab as well as open conditions.