Deep eutectic systems for carbonic anhydrase extraction from microalgae biomass to improve carbon dioxide solubilization

Abstract

This work was supported by the project “DESalgae – Capturing and re-using CO2 using deep eutectic solvents and microalgae” funded by Dutch national fund NWO Open Competition Domain Science – XS [ OCENW.XS4.162 ]; Special thanks to AlGreen B.V. (Wageningen) for providing Spirulina sp. biomass. Publisher Copyright: © 2022 The Authors.This work is the first proof-of-concept of the use of carbonic anhydrase (CA) enzyme from microalgae biomass, extracted with deep eutectic systems (DES), with the goal of engineering a solution that will lead to a breakthrough in the Carbon Capture and Utilization (CCU) strategy. Three distinct microalgae were processed-Tisochrysis lutea, Chlorella vulgaris, and Spirulina sp.-with three DES-Choline chloride-Urea (ChCl-U), Choline chloride-Poly(ethylene glycol) (ChCl-PEG), and Poly(ethylene glycol)-Urea (PEG-U). To evaluate the most promising microalgae-DES, CA activity was evaluated with a specific enzymatic activity kit and through CO2 solubility assays. Preliminary results indicate that: DES is a suitable solvent medium for CA extraction from microalgal biomass, preserving its activity (specific CA activity up to 0.70 mU.mg-1); CA extraction efficiency differs between DES and microalgal species, indicating the potential for further research; from the tested DES, the ones containing PEG were favorable to maintain CA activity (CO2 solubility up to 4 g CO2.g-1 DES). This work paves the way towards a disruptive CCU approach.publishersversionpublishe