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PublicationEnzyme and Microbial Technology
Year2016
Volume90
Pages35-44
International

OPERATIONAL STABILITIES OF DIFFERENT CHEMICAL DERIVATIVES OF NOVOZYM 435 IN AN ALCOHOLYSIS REACTION

Authors:Carlos Manuel Verdasco Martín, Roberto Fernandez-Lafuente, Cristina Otero Hernández
Groups of research:Optimización de biocatalizadores y bioprocesos enzimáticos, Biocatalysis and Bioenergy (BBG)
María Villalba, Carlos M. Verdasco-Martín, Jose C. S. dos Santos, Roberto Fernandez-Lafuente and Cristina Otero*
 
Department of Biocatalysis, Institute of Catalysis and Petroleochemistry, CSIC, C/ Marie Curie 2 L10, Madrid 28049, Spain

Industrial use of  Novozym 435 in synthesis of structured lipids and biodiesel via alcoholysis is limited by mass transfer effects of the glycerides through immobilized enzymes and t its low operational stability under operation conditions. To better understand this,differently modified Novozym 435 preparations, differing in their surface nature and in their interactions with reactants, have been  compared in the alcoholysis of Camelina Sativa oil. The  three modifications performed have been carried out under conditions where all exposed groups of the enzyme has been modified.  These modifications were: 2,4,6-trinitrobenzensulfonic acid (Novo-TNBS), ethylendiamine (Novo-EDA) and polyethylenimine (Novo-PEI). Changes in their operational performance are analyzed in terms of changes detected by scan electron microscopy in the support morphology.
The hydrophobic nature of the TNBS accelerates the reaction rate; t-ButOH co-solvent swells the macroporous acrylic particles of Lewatit VP OC 1600 in all biocatalysts, except in the case of Novo-PEI. This co-solvent only increases the maximal conversions obtained at 24h using the modified biocatalysts. t-ButOH reduces enzyme inactivation by alcohol and water. In co-solvent system, these four biocatalysts remain fully active after 14 consecutive reaction cycles of 24h, but only Novo-TNBS yields maximal conversion before cycle 5. Some deposits on biocatalyst particles could be appreciated during reuses, and  TNBS derivatization diminishes the accumulation of product deposits on the catalyst surface. Most particles of commercial Novozym® 435 are broken after operation for 14 reaction cycles. The broken particles are fully active, but they cause problems of blockage in filtration operations and column reactors. The three derivatizations studied make the matrix particles more resistant to rupture. 
Keywords:biodiesel, Enzyme immobilization, Alcoholysis, Camelina Oil, Novozym® 435, Operational Stability, Structured lipids.
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