No abstract

No abstract

BACKGROUND: The objective of this work was to assess the influence of propane pre-treatment on the esterification activities of two non-commercial lipases from Penicillium simplicissimum and Aspergillus parasiticus in the lyophilized and immobilized forms, evaluating the effect of pressure, exposure time and depressurization rate on the lipase activity by a full 2 3 experimental design.

a b s t r a c tThe present work investigates, as a first step, the influences of pressure, exposure time and depressurisation rate on the b-galactosidase activity of permeabilized cells of Kluyveromyces marxianus CCT 7082 submitted to treatment with compressed carbon dioxide, propane and n-butane. In general, results showed that the enzyme activity changes significantly, depending on the experimental conditions investigated, allowing the selection of proper operating conditions for advantageous application of this biocatalyst in hydrolysis reactions. Further, the stability of the enzyme, after high-pressure pre-treatment, was also experimentally monitored, and the results demonstrated that the activities of this biocatalyst were always higher than those of the non-treated one. Finally, evaluation of synthesis of galactooligosaccharides (GOS), using b-galactosidase without treatment and after treatment in compressed fluids, was carried out. Results indicated promising possibilities since the use of n-butane-pre-treated enzyme led to very satisfactory reaction conversions and selectivity.

No abstract