Insights on the laccase extraction and activity in ionic-liquid-based aqueous biphasic systems

abstract

Due to their catalytic properties, selectivity, and efficiency, enzymes are excellent biocatalysts. In particular, laccases are versatile multi-copper oxidases with great interest for a wide plethora of biotechnological and environmental applications. Even though several laccase-catalysed processes have been reported at an industrial level, the high costs of their downstream processing required to provide biocatalysts with high purity levels, stability and activity remains one of the main drawbacks when economically evaluating the overall processes. Aqueous biphasic systems based on ionic liquids (ILs) can be foreseen as a promising alternative approach for the extraction and activity maintenance/improvement of enzymes, essentially due to the designer solvents ability of ionic liquids. However, to take advantage of this feature and to use the full potential of IL-based aqueous biphasic systems, it is necessary to understand the effect of ILs as phase-forming constituents and how they affect the enzymes extraction and activity. In order to overcome the lack of information on this topic in the literature, in this work, IL-based aqueous biphasic systems were investigated to extract and enhance the laccase activity, in order to gather evidences that could be used to improve the enzymes downstream processing. To this end, a wide screening of imidazolium-, pyridinium-, pyrrolidinium-, piperidinium-, tetraalkylphosphonium-, and tetraalkylammonium-based ILs as phase-forming components of ABS was carried out. Furthermore, these ILs were used to create ABS combined with salts, polymers and used as adjuvants in polymer-based ABS. Most ABS comprising ILs revealed to be highly efficient extraction platforms, allowing the complete extraction of laccase for all the conditions tested, and with an enzyme activity enhancement by more than 50%. Overall, the obtained results demonstrate that laccase preferentially partitions to the most hydrophilic phase in ABS comprising ILs, both used as adjuvants or as phase-forming components, corresponding to the phase in which the IL is enriched. Furthermore, the IL chemical structure of the IL plays a significant role in the enzyme activity, where ILs with a higher number of hydroxyl groups seem to be relevant to improve the laccase activity.

keywords

PHASE-FORMING COMPONENTS; REACTIVE TEXTILE DYES; 2-PHASE SYSTEMS; TRAMETES-VERSICOLOR; PHYSICAL-PROPERTIES; SEPARATION; PAPER; WATER; DETOXIFICATION; BIOCATALYSIS

subject category

Engineering

authors

Capela, EV; Valente, AI; Nunes, JCF; Magalhaes, FF; Rodriguez, O; Soto, A; Freire, MG; Tavares, APM

Groups

G5 - Biomimetic, Biological and Living Materials

Projects

Rede Nacional de Ressonância Magnética Nuclear (PTNMR)

Projeto de Investigação Exploratória: Ana Paula Tavares (IF Ana Paula Tavares)

Towards the improvement of recombinant proteins bioprocessing using ionic liquids (IL2BioPro)

acknowledgements

This work was developed within the scope of the project CICECOAveiro Institute of Materials, UIDB/50011/2020 & UIDP/50011/2020, financed by national funds through the Portuguese Foundation for Science and Technology/MCTES. This work was also financially supported by the project IL2BioPro (PTDC/BII-BBF/030840/2017), funded by FEDER, through COMPETE2020 -Programa Operacional Competitividade e Internacionalizacao (POCI), and by national funds (OE), through FCT/MCTES. The NMR spectrometers are part of the National NMR Network (PTNMR) and are partially supported by Infrastructure Project N degrees 022161 (co-financed by FEDER through COMPETE 2020, POCI and PORL and FCT through PIDDAC). E.V. Capela and A.P.M. Tavares acknowledges FCT for the PhD grant SFRH/BD/126202/2016 and for the research contract and exploratory project IF/01634/2015, respectively. A.P.M. Tavares also acknowledges the Short Term Scientific Mission grant (ECOST-STSM-CM1206-110116068796) and financial support from COST-IL action.