Ternary blended chitosan/chitin/FE3O4 nanosupport for lipase activation and stabilization

Abstract

To overcome the drawbacks and high costs of the synthetic route to produce pentyl valerate (PeVa), i.e., a fuel additive, the biotechnological route of utilizing Rhizomucor miehei lipase conjugated to magnetite carrier support (RML-CS/CH/MNPs) is proposed. The magnetized RML-CS/CH/MNPs were developed for enabling high yield production of PeVa at relatively short reaction time (< 3 h), while facilitating easy removal of excess RML-CS/CH/MNPs. Efficacy of the developed RML-CS/CH/MNPs biocatalyst was assessed for relevant esterification factors, viz. time, enzyme loading, temperature, substrate molar ratio and stirring speed. The highest yield of PeVa (96%) was reached under an optimized condition (50∘C, using valeric acid/pentanol molar ratio of 1:2, with a lipase loading of 1.5 mg/mL, incubation time of 3 h), thus indicating the RML was catalyzing at its fullest potential due to improved activity and stability after immobilization onto CS/CH/MNPs. RML-CS/CH/MNPs retained a 90% activity after 40 days of storage and leached an initial 3.5% of the lipase likely due to insufficient rinsing during preparation. Since the RML-CS/CH/MNPs was prepared without the use of acids, it appears to be a greener catalyst for the esterification production of PeVa and presumably for other types of commercially important esters, too.