Abstract

Deep eutectic solvents (DESs) are systems formed from one or more compounds in a mixture form, to give a eutectic with a melting point much lower than either of the individual components. DESs have attracted considerable attention as green alternative solvents to conventional solvents because they are not only eco-friendly, non-toxic, and biodegradable organic compounds, but also low cost and easy to produce and share several features and properties. DESs not only have particular properties in comparison with traditional organic solvents, but also their combination with organic solvents may also show improved and desired properties. In this study, DESs were used as the solvent in buffer containing organophosphorus hydrolase enzyme, in order to optimize the enzyme reaction buffer. Different DESs such as reline (choline chloride 2:1 urea), ethaline (choline chloride 2:1 ethanol) and glyceline (choline chloride 2:1 glycerol) were selected as an adjuvant for OPH enzyme reaction buffer. Biochemical properties, thermal stability and half-life of the OPH enzyme were studied, accordingly. In the reline, a reduction in the activity of the enzyme and in ethaline and glyceline, an increase in the activity and the stability were observed when compared with the buffer. The highest activity and stability in ethaline and glyceline in molar fraction was 0.025 and 0.25, respectively.