title: Evaluation of direct transesterification of microalgae using microwave irradiation.
abstract: Nannochloropsis sp. wet biomass was directly transesterified under microwave (MW) irradiation in the presence of methanol and various alkali and acid catalyst. Two different types of direct transesterification (DT) were used; one step and two step transesterification. The biodiesel yield obtained from the MWDT was compared with that obtained using conventional method (lipid extraction followed by transesterification) and water bath heating DT method. Findings revealed that MWDT efficiencies were higher compared to water bath heating DT by at least 14.34% and can achieve a maximum of 43.37% with proper selection of catalysts. The use of combined catalyst (NaOH and H2SO4) increased the yield obtained by 2.3-folds (water bath heating DT) and 2.87-folds (MWDT) compared with the one step single alkaline catalyst respectively. The property of biodiesel produced by MWDT has high lubricating property, good cetane number and short carbon chain FAME's compared with water bath heating DT.
authors.affiliation: Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia.
authors.forename: Chee Loong
authors.initials: CL
authors.lastname: Teo
authors.affiliation: Department of Bioprocess Engineering, Faculty of Chemical Engineering, c/o Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor, Malaysia. Electronic address: ani@cheme.utm.my.
authors.forename: Ani
authors.initials: A
authors.lastname: Idris
mesh_terms: D002849:Chromatography, Gas; D004951:Esterification; D004952:Esters / Q000378:metabolism; D005227:Fatty Acids / Q000378:metabolism; D058086:Microalgae / Q000378:metabolism*; D008872:Microwaves
chemical_list: D004952:Esters; D005227:Fatty Acids
keywords: Biodiesel; Catalyst; Direct transesterification; Microalgae; Microwave irradiation