One-step processes for in situ transesterification to biodiesel and lutein extraction from microalgae Phaeodactylum using instant controlled pressure drop (DIC)

Abstract

A one-step biodiesel fabrication in situ transesterification (ISTE) process and a value adding to residual material through lutein extraction were defined in the case of microalgae Phaeodactylum. This work aims at intensifying these two processes, thus reducing energy consumption and manufacturing cost, using the wellknown instant controlled pressure drop (DIC) as a thermomechanical pretreatment. A two factor central composite design (12 samples) was used to optimize DIC processing parameters, which were the saturated steam pressure and heating time. The responses (dependent variables) were defined from the lipid extraction, the ISTE and the lutein extraction. Lipids and biodiesel, the mono-alkyl fatty acid methyl esters (FAMEs) were isolated and analyzed using an Iatroscan Thin-layer chromatography (TLC)-flame ionization detector (FID) instrument. Lutein extraction utilized an alcoholic mixture. The isolated lutein was identified by high performance liquid chromatography (HPLC). The overall results confirmed the importance of these DIC parameters and that the saturated steam pressure was the most significant parameter. Under optimized conditions, it led to an increase of about 27% in total lipids and more than 75% in FAMEs yield, as well as twice more lutein extractability, both compared with the untreated raw material.