title: Combining enzymatic esterification with conventional alkaline transesterification in an integrated biodiesel process.
abstract: An integrated biodiesel process that combines enzymatic esterification and alkaline transesterification is suggested. With focus on the enzymatic step, the paper provides proof of concept and suggestions for further process development. Hence, palm fatty acid distillate (PFAD) has been enzymatically converted to fatty acid methyl esters in a two-step process using the immobilized lipase Novozym 435 in packed-bed columns. With only a small excess of methanol, the first reaction stage could reduce the free fatty acid (FFA) content from 85% to 5%. After removal of water by simple phase separation, it was possible to lower the FFA content to 2.5% in a second reaction stage. Both reaction stages are relatively fast with suggested reaction times of 15 min in column 1 (productivity 10 kg/kg/h) and 30 min in column 2 (productivity 5 kg/kg/h), resulting in 15% FFA after column 1 and 5% FFA after column 2. A lifetime study indicated that approximately 3,500 kg PFAD/kg Novozym 435 can be treated in the first reaction stage before the enzyme has become fully inactivated. With further optimization, the enzymatic process could be a real alternative to today's sulfuric acid catalyzed process.
authors.affiliation: Novozymes, Krogshoejvej 36, 2880 Bagsvaerd, Denmark. jebk@novozymes.com
authors.forename: Jesper
authors.initials: J
authors.lastname: Brask
authors.forename: Marianne Linde
authors.initials: ML
authors.lastname: Damstrup
authors.forename: Per Munk
authors.initials: PM
authors.lastname: Nielsen
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Holm
authors.forename: Jeroen
authors.initials: J
authors.lastname: Maes
authors.forename: Wim
authors.initials: W
authors.lastname: De Greyt
mesh_terms: D055162:Biocatalysis; D056804:Biofuels; D057168:Distillation; D004800:Enzymes, Immobilized; D004951:Esterification; D005230:Fatty Acids, Nonesterified / Q000737:chemistry / Q000378:metabolism; D005656:Fungal Proteins; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D000432:Methanol / Q000737:chemistry; D000073878:Palm Oil; D010938:Plant Oils / Q000737:chemistry / Q000378:metabolism*; D013464:Sulfuric Acids / Q000737:chemistry
chemical_list: D056804:Biofuels; D004800:Enzymes, Immobilized; D005230:Fatty Acids, Nonesterified; D005656:Fungal Proteins; D010938:Plant Oils; D013464:Sulfuric Acids; D000073878:Palm Oil; C093667:Novozyme 435; D008049:Lipase; C033158:sulfuric acid; D000432:Methanol