Applied Catalysis A: General, Vol.574, 41-47, 2019
Exceptionally active and reusable nanobiocatalyst comprising lipase non-covalently immobilized on multi-wall carbon nanotubes for the synthesis of diester plasticizers
A new method for the synthesis of dicarboxylic acid esters in the presence of a new heterogeneous nanobiocatalyst consisting of Candida antarctica lipase B immobilized on multi-walled carbon nanotubes (MWCNTs) has been developed. Selection and characterization of the support for Candida antarctica lipase B (CALB) was initially performed. Pristine and modified MWCNTs of different geometries, morphologies and surface/core modifications were tested as a lipase carrier and determining that the CheapTubes (TM) MWCNTs nanobiocatalyst with a 15.7 wt.% CALB loading was the most active nanobiocatalyst. The model reaction of succinic acid with n-butanol was carried out with a 4-molar excess of alcohol and 150 mg of nanobiocatalyst per 1 mmol of succinic acid at 45 degrees C in cyclohexane. The di-n-butyl succinate was obtained with 95% yield after 3 h. The activities of the new nanobiocatalysts were compared with the benchmark Novozyme-435 and other acidic catalysts. Recycling studies demonstrated the possibility of utilizing the most active MWCNTs-lipase biocatalyst six times without any significant loss of activity. The main advantage of this study is the superior activity of the new nanobiocatalyst, which resulted in a significant reduction of reaction times as compared to those reported in the literature.
Keywords:Biocatalysis;Carbon nanotubes;Lipase;Alkyl esters of dicarboxylic acids;Plasticizers;Esterification