PRODUCTION OF Thalassiosira sp. BIOMASS UNDER DIRECT SUNLIGHT EXPOSURE

• Main Author: SUTAWIJAYA (NIM : 20510043); Pembimbing : Zeily Nurachman D.Sc, GDE
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/15758
• Institution: Institut Teknologi Bandung

Today Indonesia is being hit by the threat of oil crisis due to it domestic-oil <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> demand greater than oil production. So, efforts to find alternative energy sources <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> especially renewable energy sources are required, e.g from Thalassiosira sp. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> Algal cells produce neutral fats (triacylglycerols) that can be converted into biodiesel by transesterification. At the moment, main problems in the development of algae for biodiesel are high cost of algae production and low <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> quantity production of algae biomass. Therefore, research to find high efficiencylarge-scale algae production is required. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> In the present work, a large-scale of biomassa production of Thalassiosira sp. was carried out using 8 photobioreactors where each made of cylindrical-glass tubes <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> with 1 m length and 5.5 cm diameter, and total working-volume per batch was 16.8 L. The photobioreactor was placed outdoor under direct exposure of sunlight. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> At night, there was no lighting applied, but at day, maximum of sunlight intensity was up 150 000 lux. In the present study, Thalassiosira sp. cells were cultured in <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> both Walne and modified media with salinity of 25 ppt. Microalgae cells were harvested by centrifugation at 5500×g for 20 min. Algal cells was then dissolved in chloroform: methanol (1:1) and sonicated for 15 min to lyses the cells, and the oils were extracted by the Bligh-Dyer method in chloroform: methanol (1:1). The oil content was analyzed by mass spectroscopy method with Ag+ in acetone as the <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> complexing agent The result of the research showed that Thalassiosira sp. grew well under direct exposure of sunlight. The highest amount of algal biomass was obtained from cultures under exposure of high sunlight intensity. The average of productivity of algal biomass and oils cultured in Walne medium in the three different experimental periods was 0.7 g biomass/L culture/d and 0.42 (mu)L oil/L culture/d. <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> <br /> The mass spectroscopic spectrum showed that oil from marine microalgae Thalassiosira sp. cultured outdoor contained 5 types of triacylglycerol: PPO, POO, SLnS, OO(C12:1), and PO(C10:1), as well as one unidentified triacylglycerol. The result was different from triacylglycerol composition obtained from indoor Thalassiosira sp. culture producing POP, POO, and SOO.