abstract
Naturally occurring peroxidases are important for living organisms and have manifold utility in industries. However, lack of stability in harsh reaction conditions hinders wide applicability of such enzymes. Thus, suitable alternative is vital which can endure severe reaction conditions. As a substitute of natural peroxidase, herein, biopolymer-based polyelectrolyte complexes (PECs) coordinated with Fen+ is proposed as macromolecular peroxidase mimicking systems. Three PECs were engineered via complexation of protonated chitosan and alginate with Fe2+ (Fe2+-PEC), Fe-3+ (Fe3+-PEC), and Fe3O4 (Fe3O4-PEC), respectively. Computational study showed the Fe3+-PEC was highly stable with abundant electrostatic and intramolecular hydrogen bonding interactions. The versatility of the Fe-PECs as artificial peroxidase biocatalysts was probed by two types of peroxidase assays-ABTS oxidation in buffer systems (pH 4.0 and 7.0) and pyrogallol oxidation in organic solvents (acetonitrile, ethyl acetate and toluene). Overall, Fe3+-PEC showed remarkably high peroxidase activity both in aqueous buffers and in organic solvents, whereas, Fe3O4-PEC showed least catalytic activity. Finally, as a proof of concept, the ability of the biocatalyst to carry out deep oxidative desulphurization was demonstrated envisaging removal of dibenzothiophene from model fossil fuel in a sustainable way. (C) 2021 Published by Elsevier B.V.
keywords
HORSERADISH-PEROXIDASE; DEEP DESULFURIZATION; CO3O4 NANOPARTICLES; COMPLEX-FORMATION; ALGINATE; CHITOSAN; OPTIMIZATION; CATALYSIS; INSIGHTS
subject category
Biochemistry & Molecular Biology; Chemistry, Applied; Polymer Science
authors
Chakraborty, S; Shet, SM; Pereira, MM; Nataraj, SK; Mondal, D
our authors
Dibyendu Mondal
Post-doc Fellowship
Matheus M. Pereira
Researcheracknowledgements
The authors acknowledge CNMS, JAIN (Deemed-to-be University) for the infrastructure facilities. DM thanks SERB-DST, India for the research Grant (EEQ/2017/000417). SKN acknowledges DST-Nanomission (SR/NM/NT-1073/2016) government of India and Talent Attraction Programme funded by the Community of Madrid Spain (2017-T1/AMB5610) for financial support. NANOMISSION PROJECT SR/NM/NS-20/2014is acknowledged for using pXRD & FESEM characterization facility. DST-Technology Mission Project (DST/TMD/HFC/2K18/124G) Government of India is also acknowledge for financial support