Calorimetric and thermodynamic analysis of an enantioselective carboxylesterase from Bacillus coagulans : Insights for an industrial scale-up

Microbial carboxylesterases are valuable biocatalysts that can selectively hydrolyze a wide spectrum of esters and may find their own applicability at industrial scale. In this work, we report the calorimetric study of an atypical enantioselective carboxylesterase from Bacillus coagulans (BCE). The influence of different pH conditions (from pH 6 to 9) on BCE thermal stability was investigated through Differential Scanning Calorimetry (DSC). A complete thermodynamic analysis of the system in combination with specific activity measurements was performed for the assessment of the best working conditions for such an enzyme. The overall results indicate that the kinetic benefits deriving from the temperature rise overwhelm the thermodynamic disadvantages in terms of protein stability, being aware that the working temperature should always be kept well below the onset of the denaturation process, which may trigger aggregation effects. Although the results concern this specific enzyme, the methodological approach has a general validity and may be useful as a guideline to design enzyme optimal working conditions through calorimetric methods