MICROALGAL LIPID FROM Chaetoceros calcitrans AND ITS CONVERSION TO BIODIESEL THROUGH Ex AND In-situ TRANSESTERIFICATION

Abstract

The manufacture of biodiesel from lipids can be carried out by ex and in-situ methods. The difference lies in the continuity of lipid extraction and its transesterification into biodiesel, either separately or simultaneously. The paper reported the FAME productivity from lipid Chaetoceros calcitrans that were created by both methods. The research was started by culturing Chaetoceros calcitrans in seawater media with the addition of trace elements, it produced a dry cell weight of 15 g/L on the fifth day of fermentation. The highest yield of lipid was 61.40% (w/w) obtained when the extraction was carried out from the biomass in a mixed solvent between n-hexane and 96% ethanol (1:1) assisted by a combination of hydrothermal acid and ultrasonication treatments. The transesterification of lipid that was carried out with methanol and 6% (v/v) H2SO4 catalyst for one hour at 60oC in an ex-situ process, produced FAME of 19.15% (w/w). Meanwhile, the in-situ method which joined the lipid repealing and transesterification steps simultaneously produced 21.59% (w/w) of biodiesel. The in-situ process exhibited higher FAME than the ex-situ. The main FAME component on the biodiesel of Chaetoceros calcitrans was methyl oleic (C17H33COOCH3, C18:1(Δ9 )). With insight into the cell’s pre-treatment and simultaneous process of the in-situ method, it is feasible to apply the techniques for biodiesel production in the future