Investigation of the causes of deactivation–degradation of the commercial biocatalyst Novozym® 435 in ethanol and ethanol–aqueous media

Towards a green enantiomeric esterification of R/S-ketoprofen: A theoretical and experimental investigation

“…S5 and S6 in the supplementary information). forms the internal core of the biocatalyst's beads [29,31]. Similarly to those observations, the extended exposure to methanol and 1-propanol shows a similar trend.…”

“…Details of the equipment used in this investigation have been published before [29,31,32]. The samples (49.9 mg) were heated up to 400 • C at 10 • C/min under a flow of pure helium (35 cm 3 (NTP) min −1 ) for the temperature programmed desorption experiment.…”

Current status and new developments of biodiesel production using fungal lipases

“…Moreover, other negative aspects are the mass transfer limitation in regards to the molecular sizes of substrates and products [2] and the effect of alcohol in contact with the immobilized biocatalyst. José et al [52] observed that ethanol was able to dissolve the polymethylmethacrylate (PMMA) that constitutes the support of Novozym 435. Ethanol also diffused into the biocatalyst's beads, remaining strongly adsorbed and altering the inner texture of the beads.…”

“…Other examples of wastes include: palm oil mill effluent (POME), a waste from palm oil wet milling; oil waste from fast food services; wastewater and sewage sludge [106]. Lignocellulosic raw materials, after a pretreatment in order to produce fermented monomers, have also been studied for microbial oil production [52,113]. Zhao et al [104] observed that the fatty acid composition of the yeast lipid from R. toruloides, obtained by fermentation using lignocellulosic hydrolyzate as substrate, was in the range of those of various plant oils and animal tallow.…”

“…However, several works had recognized that proteins are easily inactivated in the presence of short chain alcohols, such as ethanol and methanol, which are insoluble in oil and may interact with the water molecules necessary for the maintenance of the native structure of the lipase [31,40,79,86,88,[116][117][118][119]. José et al [52] observed that ethanol changes the secondary structure of the CALB lipase by decreasing the a-helix contributions and increasing the b-sheet structure. Alcohols with more than three carbons are more soluble in the vegetable oil and, therefore less harmful to the enzyme [3,117,119].…”