title: In situ biodiesel production from greasy sewage sludge using acid and enzymatic catalysts.
abstract: This study proposes to select the most appropriate sewage sludge (greasy, primary and secondary) for in situ transesterification and to compare the technical, economic and energetic performance of an enzymatic catalyst (Novozym®435) with sulfuric acid. Greasy sludge was selected as feedstock for biodiesel production due to its high lipid content (44.4%) and low unsaponifiable matter. Maximum methyl esters yield (61%) was reached when processing the wet sludge using sulfuric acid as catalyst and n-hexane, followed by dried-greasy sludge catalyzed by Novozym®435 (57% methyl esters). Considering the economic point of view, the process using acid catalyst was more favorable compared to Novozym®435 catalyst due to the high cost of lipase. In general, greasy sludge (wet or dried) showed high potential to produce biodiesel. However, further technical adjustments are needed to make biodiesel production by in situ transesterification using acid and enzymatic catalyst feasible.
authors.affiliation: Laboratory of Oils and Fats, Department of Agro-food Industry, Food and Nutrition, College of Agriculture "Luiz de Queiroz" (ESALQ), University of São Paulo, Piracicaba, São Paulo, Brazil. Electronic address: naisangaletti@yahoo.com.br.
authors.forename: Naiane
authors.initials: N
authors.lastname: Sangaletti-Gerhard
authors.affiliation: Scientific and Technological Bioresources Nucleus, University of La Frontera, Temuco, Chile; Department of Chemical Engineering, University of La Frontera, Temuco, Chile. Electronic address: mara.cea@ufrontera.cl.
authors.forename: Mara
authors.initials: M
authors.lastname: Cea
authors.affiliation: Scientific and Technological Bioresources Nucleus, University of La Frontera, Temuco, Chile. Electronic address: v.risco01@ufromail.cl.
authors.forename: Vicky
authors.initials: V
authors.lastname: Risco
authors.affiliation: Scientific and Technological Bioresources Nucleus, University of La Frontera, Temuco, Chile; Department of Chemical Engineering, University of La Frontera, Temuco, Chile; Centre for Biotechnology & Bioengineering (CeBiB), Chile. Electronic address: rodrigo.navia@ufrontera.cl.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Navia
mesh_terms: D056804:Biofuels; D001709:Biotechnology / Q000191:economics / Q000379:methods*; D002384:Catalysis / Q000187:drug effects; D004800:Enzymes, Immobilized; D004951:Esterification; D004952:Esters; D005227:Fatty Acids / Q000032:analysis; D005656:Fungal Proteins; D008049:Lipase / Q000378:metabolism*; D012722:Sewage / Q000737:chemistry*; D013464:Sulfuric Acids / Q000494:pharmacology*; D013816:Thermodynamics
chemical_list: D056804:Biofuels; D004800:Enzymes, Immobilized; D004952:Esters; D005227:Fatty Acids; D005656:Fungal Proteins; D012722:Sewage; D013464:Sulfuric Acids; C093667:Novozyme 435; D008049:Lipase; C033158:sulfuric acid
keywords: Cosolvent; Methyl esters; Novozym®435; Wastewater