Biodiesel Production by In Situ Transesterification of Microalgae Chlamydomonas sp., and Synechococcus sp. Cultivated in a Technical Grade Media

Abstract

During the time being, the world’s oil supply is going to be less. In the other side, enviroment pollution derived from fosil fuel combustion is going tobe more extensive. Indonesia has 9 billion barrel of oil reserve which will be run out in 23 years. Therefore, alternative source of energy should be developed, such as biodiesel. Microalgae have a high productivity and potential to be developed as biodiesel. This development need a high cost. This study is intended to find an alternativeof biodiesel production from microalgae which is more cost efficient. We developed a new improvement by using technical grade culture nutrient and in situtransesterification process. The study consisted of three stages. The first was regeneration and providing four isolates in BG 11 medium. The second was cultivation in lab scale, aquarium scale using N2P1, N2P2 or N3P3 medium, and analyses of lipid, water, ash, yield, free fatty acid (FFA), and characterization of the fatty acid. The last was biodiesel production byin situtransesterification process,yield measurement and characterization of the biodiesel. Isolate Chlamydomonas sp. ICBB 9114 produced the highest yield of biomass (0.44 g/L) with low water content, whileChlamydomonas sp. ICBB 9112 produced the lowest biomass (0.19 g/L) with the highest water and FFA content. Synechococcus sp. ICBB 9111 had the highest ash content, whileChlamydomonas sp. ICBB 9113 had the lowest ash and FFA content. Fatty acid content with C18:3 type was dominant in Synechococcus sp. ICBB 9111 (47.03%), Chlamydomonas sp. ICBB 9113 (42.57%), and Chlamydomonas sp. ICBB 9114 (34.42%). While, C16:0 type was dominant in Chlamydomonas sp. ICBB 9112. It marked that Chlamydomonas sp. ICBB 9112 had a good quality of FA which could be used as biodiesel needing a low melting point, high cetan number, and unoxidizable. After lipid extraction, the process was continued with convertion to fatty acid metyl ester (FAMEs) through transesterification process. Chlamydomonas sp. ICBB 9114 produced the highest FAMEs (3523.20 mg/100 g). The characteristics of the biodiesel originated fromChlamydomonas sp. ICBB 9114 producedby in situ transesterficationwere suitable with SNI biodiesel criteria except for the acid value.