(133e) Biocatalysis and Chemcial Engineering Fundamentals: A Symbiosis

Enzymes are great catalysts but often need to be optimized for selectivity and stability for satisfactory operation under process conditions. Reaching beyond the melting temperature Tm (indicating thermodynamic stability), the dimensionless Total Turnover Number TTN (average number of turnover per active site over the (bio)catalyst’s lifetime) indicates process stability as well as the (bio)catalyst cost contribution. We will demonstrate that TTN can be viewed from the angle of classical dimensionless numbers.[1]

A good rate law is the basis for reactor design. We will report on two cases of unexpected enzyme inhibitions under process conditions, in contrast to dilute, homogeneous aqueous buffer.[2,3] With an accurate kinetic model of all rate processes involved, Pareto analysis and application of Green Chemistry criteria then enable simultaneous biocatalyst development and reactor design.[2]

Biooxidations catalyzed by oxidases often require molecular O2 as co-substrate, creating air-water interfaces in reactors. NADH oxidase (Nox2) from Lactobacillus plantarum shows a peculiar two-stage deactivation behavior in bubble columns, with two different slopes in a semi-logarithmic plot. We elucidated the likely origin of this behavior, combined enzyme adsorption and deactivation.[4]

[1] AS Bommarius, to be submitted

[2] CE Lagerman et al., Frontiers Bioeng. Biotech. 2022, 10, 826357

[3] MA McDonald et al., Crystal Growth & Design 2019, 19, 5065-5074

[4] AV Høst et al., Chem. Eng. Sci. 2024, 297, 120282