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Laccase activity and stability in the presence of menthol-based ionic liquids

100%
Feder-Kubis J., Bryjak J.
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2013
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vol. 60
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issue 4
741-745
EN
Laccases attract attention due to their potential for manufacturing pharmaceutical intermediates from a wide array of phenolic and non-phenolic substrates that are sparingly soluble in water. Because of the high polarity of ionic liquids (ILs), they can dissolve polar and nonpolar compounds and are claimed as "green" alternative for volatile organic solvents. The main aim of this work was to find water-immiscible ILs suitable for Cerrena unicolor laccase. For that five ILs with bis(trifluoromethanesulfonyl)imide anions coupled with cations derived from natural alcohol - (1R,2S,5R)-(-)-menthol were synthesized, namely: (I) 3-butyl-1-[(1R,2S,5R)-(-)-menthoxymethyl]imidazolium, (II) 1-[(1R,2S,5R)-(-)-menthoxymethyl]-3-heptylimidazolium, (III) 1-[(1R,2S,5R)-(-)-menthoxymethyl]-3-methylpyridinium, (IV) heptyl[(1R,2S,5R)-(-)-menthoxymethyl]dimethylammonium, and (V) decyl[(1R,2S,5R)-(-)-menthoxymethyl]dimethylammonium ions. Laccase activity was tested in buffer saturated with ILs whereas stability tests in biphasic systems lasted 5 days. It was shown that ILs I, III-V did not significantly alter laccase activity (being 90-123% respective to the buffer) whereas IL II decreased reactivity in 20%. Stability tests revealed that ILs I, IV and V increased enzyme stability even more than in the buffer. For mathematical formalization of inactivation courses, isoenzyme model was applied but this model fitted experimental data only for sets obtained in the buffer (control) and in the presence of IL II. In the other cases, first-order reaction model was sufficient. This shows that ILs, even at very low concentrations, influence conformational stability of proteins, which is dependent on the cation structure. In general, the imidazolium (I) and ammonium (IV) salts with shorter alkyl chains supported laccase activity and stability.
2

Membrane reactor - new possibilities

100%
Noworyta A., Bryjak J.
Biotechnologia
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1993
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issue 3
4-15
EN
The flow-sheet of for biotechnological application has been presented in the paper. The relevant topics that concern problems of microbial or as well as separation of reaction system onto the fractions with different residence time distributions have been overiewed. A set of conditions has been specified for membranes applied in the system. The following types of bioreactors have been characterized in detail i.e.:i) case of bioreactor for hydrolysis of penicillinum G and ii) case of microbial membrane bioreactor for culture and harvesting of biomass iii) microbial membrane bioreactor for alcohol fermentation.
3
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Laccase Immobilisation on Mesostructured Silicas

81%
Bryjak J., Szymańska K., Jarzębski A. B.
Chemical and Process Engineering
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2012
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vol. 33
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issue 4
611-620
EN
Extracellular laccase produced by the wood-rotting fungus Cerrena unicolor was immobilised covalently on the mesostructured siliceous foam (MCF) and three hexagonally ordered mesoporous silicas (SBA-15) with different pore sizes. The enzyme was attached covalently via glutaraldehyde (GLA) or by simple adsorption and additionally crosslinked with GLA. The experiments indicated that laccase bound by covalent attachment remains very active and stable. The best biocatalysts were MCF and SBA-15 with Si-F moieties on their surface. Thermal inactivation of immobilised and native laccase at 80°C showed a biphasic-type activity decay, that could be modelled with 3- parameter isoenzyme model. It appeared that immobilisation did not significantly change the mechanism of activity loss but stabilised a fraction of a stable isoform. Examination of time needed for 90% initial activity loss revealed that immobilisation prolonged that time from 8 min (native enzyme) up to 155 min (SBA-15SF).
4
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Screening of lipase carriers for reactions in water, biphasic and pure organic solvent systems

61%
Hrydziuszko Z., Dmytryk A., Majewska P., Szymańska K., Liesiene J., Jarzębski A., Bryjak J.
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2014
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vol. 61
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issue 1
1-6
EN
In bioprocesses lipases are typically used in immobilized form, irrespective of type of reaction systems, to ensure an even distribution of catalysts in water restricted media and/or to facilitate separation and reuse. In these studies we report on the selection of appropriate enzyme-carrier preparation for hydrolysis reaction in aqueous and biphasic systems and transesterification in organic solvent. For this Candida rugosa lipase was bound by adsorption or covalent attachment onto various carriers to give 24 preparations. Selection of proper preparation was based on reactivity, thermal stability (4 h at 60°C), possibility of drying and operational stability in 17-23 successive batch processes of 4-nitrophenyl palmitate hydrolysis in water. Activity of preparations varied from 20 to 5100 U∙mL-1 but the most stable preparations were those of moderate activity: bound by adsorption or covalent attachment to NH2-Kieselgel or acrylic carrier (retained activity over 90%). Selected preparations were used for hydrolysis of ethyl (1-butyryloxyethyl)-phenylphosphinate in biphasic system, and, after drying, in ethyl (1-hydroxyethyl)-phenyl-phosphinate transesterification. In this study operational stability was the principal criterion of selection. In water system, lipase covalently bound to NH2-Kieselgel was the best - preserved 50% of initial activity in consecutive batch processes. In biphasic system and lipase covalently bound to acrylic and NH2-Kieselgel the values were 90 or 77%, respectively, whereas in organic solvent, when lipase was immobilized on NH2-Kieselgel by adsorption, it was 50%. Thus, NH2-Kieselgel appears to be an universal matrix for investigated lipase immobilization and can be used in all reaction systems.
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