%0 Journal Article %T Production of Biodiesel from Lipid of Porphyridium cruentum through Ultrasonic Method %A Raymond Kwangdinata %A Indah Raya %A Muhammad Zakir %J ISRN Renewable Energy %D 2014 %R 10.1155/2014/107278 %X A research on production of biodiesel from lipid of phytoplankton Porphyridium cruentum through ultrasonic method has been done. In this research, we carried out a series of phytoplankton cultures to determine the optimum time of growth and biodiesel synthesis process from phytoplankton lipids. Process of biodiesel synthesis consists of two steps, that is, isolation of phytoplankton lipids and biodiesel synthesis from those lipids. Oil isolation process was carried out by ultrasonic extraction method using ethanol 96%, while biodiesel synthesis was carried out by transesterification reaction using methanol and KOH catalyst under sonication. Weight of biodiesel yield per biomass Porphyridium cruentum is 40,27%. Characterization of biodiesel was well carried out in terms of physical properties which are density and viscosity and chemical properties which are FFA content, saponification value, and iodine value. These values meet the American Society for Testing and Materials (ASTM D6751) standard levels, except for the density value which was 0.9461 g¡¤cm£¿3 and the FFA content which was 4.6671%. 1. Introduction That energy crisis is attacking the world today is a problem that must be resolved and addressed. The continuous exploitation of the fossil fuels which are nonrenewable energy resulted in dwindling existence. This will have an impact on the scarcity of fossil fuels, thereby increasing the price of fuel oil (BBM) world. This situation has made most of the countries in the world (one of them is Indonesia) seek sources of alternative fuel that can be developed from other basic materials that are renewable and environmentally friendly [1]. Therefore, to meet the level of oil consumption and encourage the development and utilization of renewable alternative energy, biofuels 1 (biofuels) such as biodiesel can be used [2]. Earth is mostly composed of water environment which is rich of potential renewable resources, especially in Indonesian waters. Indonesia has the chance of being the biofuels producing country as we know that Indonesia has the immense of the natural capital, especially the environmental water. Indonesia is an archipelago with two-thirds of the area being the sea and the longest coastline in the world, which is 80,791.42£¿km, and is rich in aquatic biological resources, which are very abundant in both kind and quantity. One of Indonesia¡¯s natural potential is microalgae or phytoplankton, which can be used as an alternative source of biodiesel, because it contains lipid, in addition to protein, carbohydrates, and vitamins. The lipid content %U http://www.hindawi.com/journals/isrn.renewable.energy/2014/107278/