Efficient Chemo‐Enzymatic Epoxidation Using silcoat‐Novozym^®435: Characterizing the Multiphase System

Abstract

Silicone composites of Novozym®435 (silcoat-NZ435) demonstrate improved leaching and mechanical stability compared to native Novozym®435 (NZ435). Here, the application scope of this novel enzyme preparation has been broadened significantly by the transfer from single-phase esterification to a complex chemoenzymatic epoxidation reaction in a three-phase system. The reaction gave up to 80 % yields with almost 100 % selectivity in 50 h when operated in the absence of mass transfer limitations. Characterization of the system revealed that octanoic acid inhibited the reaction at concentrations around 6 M. The silcoat-NZ435 catalyst could be reused over five days with less than 50 % loss in activity when 5 M H 2 O 2 was present. H 2 O 2 was also identified as the component which deactivates the enzyme at high concentration (17.5 M) demanding spatial separation of the silcoat-NZ435 for optimal operation.

Produktion von Peroxyoktansäure mittels immobilisierter CalB: Realisierbarkeitsstudie im einphasigen Stoffsystem mit graduellem Wasserstoffperoxid‐Dosing

“…The pinene oxide concentration was found to depend much stronger on the residence time than on the peracid concentration from just the enzymatic step (section 4.2.3). This indicates the epoxidation again as the rate-limiting step in accordance with other reports [31,42,146,149]. Shorter residence times led to higher H 2 O 2 concentrations in the reactor and thus to a rearrangement of α-pinene, which is known to depend on the H 2 O 2 concentration [35].…”

“…Besides the influence on the selectivity, peroxides can destroy the lipases' three-dimensional structure irreversibly by oxidizing cysteine and other functions of the protein [102]. Long-term enzyme activity is commonly estimated in terms of reusability by performing recycle experiments [28,36,146] which include, e.g., the influence of storage and solvent drying on the enzyme support. These effects might overlap or mask the deactivation due to the presence of peroxides.…”

Novozym 435: the “perfect” lipase immobilized biocatalyst?

“…532 In another instance, the silicone-coated biocatalyst was used in a complex chemo-enzymatic epoxidation reaction in a three-phase system. 533 The biocatalyst kept 50% of the activity after 5 days in 5 mM hydrogen peroxide. In another research study, the syntheses of polyIJethylene glycol) 400-coconut fatty acid monoester, myristyl myristate and propylene oxide copolymer-oleic acid, and ethylene oxide diester were studied with N435 and N435 treated with silicone.…”

A continuous single organic phase process for the lipase catalyzed synthesis of peroxy acids increases productivity

“…a, Table ) shown in the FBS experiments. To estimate the long‐term enzyme activity or rather reusability, recycle experiments are commonly applied . These, however, include, e.g., the influence of storage and solvent drying on the enzyme support, which leads to overlapping or masking of the deactivation caused by hydrogen peroxide.…”