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Physical and Chemical Lipase Adsorption on SBA‐15: Effect of Different Interactions on Enzyme Loading and Catalytic Performance
Author(s) -
Salis Andrea,
Casula Maria F.,
Bhattacharyya Mani S.,
Pinna Marcella,
Solinas Vincenzo,
Monduzzi Maura
Publication year - 2010
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.200900288
Subject(s) - lipase , physisorption , pseudomonas fluorescens , catalysis , adsorption , mesoporous silica , chemistry , surface modification , chemical engineering , hydrolysis , mesoporous material , active site , sunflower oil , materials science , organic chemistry , nuclear chemistry , enzyme , biochemistry , engineering , genetics , biology , bacteria
Immobilization of Pseudomonas fluorescens lipase (Pfl) on the chemically modified, or unmodified, surface of SBA‐15 mesoporous silica has been achieved. X‐ray diffraction (XRD), transmission electron microscopy (TEM), and N 2 physisorption are used to monitor the effect of surface functionalization on the structural and textural features of the SBA‐15 silica support. The enzyme loading strongly depends on the type of enzyme–support interaction, the maximal loading of the chemisorbed lipase being about twice that of the physisorbed (502 and 256 mg protein ${{\rm g}{{- 1\hfill \atop {\rm support}\hfill}}}$ respectively). The resulting biocatalysts, regardless of the different loading, are tested with a hydrolytic catalytic assay. Despite the lower loading, the physically immobilized Pfl is more active than that which is chemically immobilized. Both biocatalysts are also active in a green process for biodiesel production, leading to almost full conversion of sunflower oil and ethanol into the corresponding ethyl esters after about 7 h at 30 °C, atmospheric pressure, and in solvent‐free conditions. Recycling experiments showed that the chemically immobilized Pfl was still active after twenty reaction cycles whereas the physically immobilized Pfl lost its activity after the tenth cycle.