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Use of Candida rugosa lipase immobilized on sepabeads for the amyl caprylate synthesis: Batch and fluidized bed reactor study Svetlana Saponjić1 · Zorica D. Knežević-Jugović*1 · Dejan I. Bezbradica1 · Milena G. Zuza1 · Omar Ali Saied1 · Nevenka Bosković-Vragolović2 · Dusan Z. Mijin3 1Department
of Biotechnology and Biochemical Engineering, Faculty of Technology and
Metallurgy, University of Belgrade, Belgrade, Serbia *Corresponding author: zknez@tmf.bg.ac.rs Financial support: This work was financed by the Ministry of Science and Technological Development of the Republic of Serbia (Project No. TR-20064). Keywords: bioreactors, covalent immobilization, ester, non-aqueous system, optimization technique.
Lipase from Candida rugosa was covalently immobilized on Sepabeads EC-EP for application for amyl caprylate synthesis in an organic solvent system. Several solvents were tested in terms of biocatalyst stability and the best result was obtained with isooctane. The lipase-catalyzed esterification in the selected system was performed in batch and fluidized bed reactor systems. The influence of several important reaction parameters including temperature, initial water content, enzyme loading, acid/alcohol molar ratio, and time of addition of molecular sieves is carefully analyzed by means of an experimental design. Almost complete conversion (> 99%) of the substrate to ester could be performed in a batch reactor system, using lipase loading as low as 37 mg g-1 dry support and in a relatively short time (24 hrs) at 37ºC, when high initial substrate molar ratio of 2.2 is used. Kinetics in a fluidized bed reactor system seems to still have a slightly better profile than in the batch system (90.2% yields after 14 hrs). The fluidized bed reactor operated for up 70 hrs almost with no loss in productivity, implying that the proposed process and the immobilized system could provide a promising approach for the amyl caprylate synthesis at the industrial scale. |