title: Application of a chitosan-immobilized Talaromyces thermophilus lipase to a batch biodiesel production from waste frying oils.
abstract: Waste frying oil, which not only harms people's health but also causes environmental pollution, can be a good alternative to partially substitute petroleum diesel through transesterification reaction. This oil contained 8.8 % of free fatty acids, which cause a problem in a base-catalyzed process. In this study, synthesis of biodiesel was efficiently catalyzed by the covalently immobilized Talaromyces thermophilus lipase and allowed bioconversion yield up to 92 % after 24 h of reaction time. The optimal molar ratio was four to six parts of methanol to one part of oil with a biocatalyst loaded of 25 wt.% of oil. Further, experiments revealed that T. thermophilus lipase, immobilized by a multipoint covalent liaison onto activated chitosan via a short spacer (glutaraldehyde), was sufficiently tolerant to methanol. In fact, using the stepwise addition of methanol, no significant difference was observed from the one-step whole addition at the start of reaction. The batch biodiesel synthesis was performed in a fixed bed reactor with a lipase loaded of 10 g. The bioconversion yield of 98 % was attained after a 5-h reaction time. The bioreactor was operated successfully for almost 150 h without any changes in the initial conversion yield. Most of the chemical and physical properties of the produced biodiesel meet the European and USA standard specifications of biodiesel fuels.
authors.affiliation: Laboratory of Biomass Valorization and Proteins Production in Eukaryotes, Center of Biotechnology of Sfax, University of Sfax, PB 1177, 3038, Sfax, Tunisia, inesbelhaj@yahoo.fr.
authors.forename: Ines Belhaj-Ben
authors.initials: IB
authors.lastname: Romdhane
authors.forename: Zamen Ben
authors.initials: ZB
authors.lastname: Romdhane
authors.forename: Maha
authors.initials: M
authors.lastname: Bouzid
authors.forename: Ali
authors.initials: A
authors.lastname: Gargouri
authors.forename: Hafedh
authors.initials: H
authors.lastname: Belghith
mesh_terms: D056804:Biofuels; D019149:Bioreactors; D048271:Chitosan / Q000737:chemistry*; D004800:Enzymes, Immobilized / Q000737:chemistry; D004951:Esterification; D006801:Humans; D008049:Lipase / Q000737:chemistry*; D000432:Methanol / Q000737:chemistry; D010938:Plant Oils / Q000737:chemistry; D032901:Talaromyces / Q000737:chemistry; D014866:Waste Products
chemical_list: D056804:Biofuels; D004800:Enzymes, Immobilized; D010938:Plant Oils; D014866:Waste Products; D048271:Chitosan; D008049:Lipase; D000432:Methanol