Workpackage 3: Reaction optimization and up-scaling of photobiocatalysis
WP3 aims at identifying and optimizing key physiological parameters e.g. cultivation concepts and reactor forms for cyanobacteria, amounts of catalytic components, light-intensity, temperature, pH, organic solvent, hydrophobicity, water-activity, etc. for product formation, intracellular NADPH amounts, space-timeyield, and turnover numbers.
WP3 focuses on achieving high product titers (≥50 g/L) and space-time-yields (≥15g/(L×h)). For higher enzyme stability (aqueous or organic media) and for enzyme reuse, different immobilization techniques will be evaluated. Photocatalysis in low-water media will be optimized by rigorous evaluation of organic solvents, as well as by using alternative reducing equivalents. Up-scaling of strains (up to 25 L, two model enzymes introduced in chassis systems by UPo) will be done together with the industrial partner after identifying parameters for synthesis at large scales. Up-scaling of the photocatalysis for ADHcatalyzed diol oxidation and for UPo-catalyzed cyclohexane hydroxylation will be demonstrated. Furthermore, photocatalytic strategies developed within the EJD program will be evaluated in terms of enzyme consumption, volumetric productivity, and waste generated.