Increasing content of lipid in tropical microalgae Chlorella sorokiniana and Closterium sp. with variation of nitrogen content and extraction temperature

Environmental Engineering Departement, Faculty of Landscape Architecture and Environmental Technology, Universitas Trisakti, Jakarta, Indonesia

^* Corresponding author: astririnanti@trisakti.ac.id

Abstract

This research was aimed to obtain algae biofuels as an alternative energy which comes from tropical microalgae biomass Chlorella sorokiniana and Closterium sp. The cultivation was performed at a controlled room in batch culture photobioreactor, temperature 27°C, pH 6, aeration with air flow rate of 150 mL/sec, and light intensity at 2400 lux. These nutrient sources used artificial PHM with KNO₃ variation as a nitrogen source of 0 grams; 0.25 grams; 0.5 grams; 1 gram. The research involved microalgae lipid extraction with Blight & Dyer method and also carried out support of alcohol, chloroform and distilled water (1:1:1) with optimum temperature 30oC. Oil yields that obtained were analyzed with Gas Chromatography Mass Spectrometry (GC-MS) method, dry weight with a gravimetric method and cell density with spectrophotometry. The result showed that the reduction of KNO₃ materials (0,25 gr) can produce biomass and highest total lipid content at 0,41 g/L and 20,31 %/(w/w). The results showed that KNO₃ decreased the amount of biomass which was not significant but the total lipid content of microalgae was increased. Lipid content and fatty acids extracted from Blight & Dyer showed oil content that could potentially be the raw material of biodiesel.