title: Biodiesel synthesis by direct transesterification of microalga Botryococcus braunii with continuous methanol reflux.
abstract: Direct transesterification of Botryococcus braunii with continuous acyl acceptor reflux was evaluated. This method combines in one step lipid extraction and esterification/transesterification. Fatty acid methyl esters (FAME) synthesis by direct conversion of microalgal biomass was carried out using sulfuric acid as catalyst and methanol as acyl acceptor. In this system, once lipids are extracted, they are contacted with the catalyst and methanol reaching 82%wt of FAME yield. To optimize the reaction conditions, a factorial design using surface response methodology was applied. The effects of catalyst concentration and co-solvent concentration were studied. Hexane was used as co-solvent for increasing lipid extraction performance. The incorporation of hexane in the reaction provoked an increase in FAME yield from 82% (pure methanol) to 95% when a 47%v/v of hexane was incorporated in the reaction. However, the selectivity towards non-saponifiable lipids such as sterols was increased, negatively affecting biodiesel quality.
authors.affiliation: Scientific and Technological Bioresources Nucleus, Universidad de La Frontera, Casilla 54-D, Temuco, Chile. Electronic address: p.hidalgo02@ufromail.cl.
authors.forename: Pamela
authors.initials: P
authors.lastname: Hidalgo
authors.affiliation: Scientific and Technological Bioresources Nucleus, Universidad de La Frontera, Casilla 54-D, Temuco, Chile; Departament of Chemical Engineering, Universidad de La Frontera, Casilla 54-D, Temuco, Chile. Electronic address: gustavo.ciudad@ufrontera.cl.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Ciudad
authors.affiliation: Institute of Chemistry, Working Group Chemistry and Technology of Renewable Resources, NAWI Graz, University of Graz, Heinrichstraße 28, A-8010 Graz, Austria. Electronic address: si.schober@uni-graz.at.
authors.forename: Sigurd
authors.initials: S
authors.lastname: Schober
authors.affiliation: Institute of Chemistry, Working Group Chemistry and Technology of Renewable Resources, NAWI Graz, University of Graz, Heinrichstraße 28, A-8010 Graz, Austria. Electronic address: martin.mittelbach@uni-graz.at.
authors.forename: Martin
authors.initials: M
authors.lastname: Mittelbach
authors.affiliation: Scientific and Technological Bioresources Nucleus, Universidad de La Frontera, Casilla 54-D, Temuco, Chile; Departament of Chemical Engineering, Universidad de La Frontera, Casilla 54-D, Temuco, Chile; Centre for Biotechnology and Bioengineering (CeBiB), Universidad de La Frontera, Casilla 54-D, Temuco, Chile. Electronic address: rodrigo.navia@ufrontera.cl.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Navia
mesh_terms: D056804:Biofuels; D018533:Biomass; D019149:Bioreactors / Q000382:microbiology; D001709:Biotechnology / Q000379:methods*; D000460:Chlorophyta / Q000187:drug effects / Q000378:metabolism*; D004951:Esterification / Q000187:drug effects; D004952:Esters / Q000032:analysis; D005227:Fatty Acids / Q000032:analysis; D000432:Methanol / Q000494:pharmacology*; D058086:Microalgae / Q000187:drug effects / Q000378:metabolism*
chemical_list: D056804:Biofuels; D004952:Esters; D005227:Fatty Acids; D000432:Methanol
keywords: Acyl acceptor; Botryococcus braunii; Co-solvent; Direct transesterification; Hexane