Abstract: Lutein is a dietary oxycarotenoid which is found
to reduce the risks of Age-related Macular Degeneration
(AMD). Supercritical fluid extraction of lutein esters from
marigold petals was carried out and was found to be much
effective than conventional solvent extraction. The
saponification of pre-concentrated lutein esters to produce free
lutein was studied which showed a composition of about 88%
total carotenoids (UV-VIS spectrophotometry) and 90.7%
lutein (HPLC). The lipase catalyzed hydrolysis of lutein esters
in conventional medium was investigated. The optimal
temperature, pH, enzyme concentration and water activity
were found to be 50°C, 7, 15% and 0.33 respectively and the
activity loss of lipase was about 25% after 8 times re-use in at
50°C for 12 days. However, the lipase catalyzed hydrolysis of
lutein esters in conventional media resulted in poor
conversions (16.4%).
Abstract: Plackett-Burman statistical screening of media
constituents and operational conditions for extracellular lipase
production from isolate Trichoderma viride has been carried out in
submerged fermentation. This statistical design is used in the early
stages of experimentation to screen out unimportant factors from a
large number of possible factors. This design involves screening of
up to 'n-1' variables in just 'n' number of experiments. Regression
coefficients and t-values were calculated by subjecting the
experimental data to statistical analysis using Minitab version 15.
The effects of nine process variables were studied in twelve
experimental trials. Maximum lipase activity of 7.83 μmol /ml /min
was obtained in the 6th trail. Pareto chart illustrates the order of
significance of the variables affecting the lipase production. The
present study concludes that the most significant variables affecting
lipase production were found to be palm oil, yeast extract, K2HPO4,
MgSO4 and CaCl2.
Abstract: Lipases are enzymes particularly amenable for
immobilization by entrapment methods, as they can work equally
well in aqueous or non-conventional media and long-time stability of
enzyme activity and enantioselectivity is needed to elaborate more
efficient bioprocesses. The improvement of Pseudomonas
fluorescens (Amano AK) lipase characteristics was investigated by
optimizing the immobilization procedure in hybrid organic-inorganic
matrices using ionic liquids as additives. Ionic liquids containing a
more hydrophobic alkyl group in the cationic moiety are beneficial
for the activity of immobilized lipase. Silanes with alkyl- or aryl
nonhydrolizable groups used as precursors in combination with
tetramethoxysilane could generate composites with higher
enantioselectivity compared to the native enzyme in acylation
reactions of secondary alcohols. The optimal effect on both activity
and enantioselectivity was achieved for the composite made from
octyltrimethoxysilane and tetramethoxysilane at 1:1 molar ratio (60%
increase of total activity following immobilization and enantiomeric
ratio of 30). Ionic liquids also demonstrated valuable properties as
reaction media for the studied reactions, comparable with the usual
organic solvent, hexane.