Enzyme engineering aspects of biocatalysis: cofactor regeneration as example

Area of Science:

• Biocatalysis
• Chemical Engineering
• Enzyme Technology

Background:

• Cofactor-dependent enzymes are crucial for synthesizing chiral compounds like amino acids and alcohols.
• High cofactor costs can limit the economic viability of enzymatic processes.
• Reaction engineering strategies are needed to improve cofactor utilization and reduce overall production expenses.

Purpose of the Study:

• To demonstrate how reaction engineering can minimize cofactor costs in enzyme-catalyzed reactions.
• To explore continuous processing methods for efficient cofactor recycling.
• To achieve high yields and turnover numbers for valuable chiral products.

Main Methods:

• Utilized continuous enzyme membrane reactors for stereospecific reduction of carbonyl compounds.
• Implemented product extraction and cofactor recycling strategies within bioreactors.
• Employed polymer-enlarged nicotinamide adenine dinucleotide (NADH) for enhanced cofactor performance.

Main Results:

• Achieved high space-time yields for L-tert-Leucine (up to 366 g L(-1) d(-1)) and (S)-1-Phenyl-2-propanol (63 g L(-1) d(-1)).
• Demonstrated extensive cofactor recycling, with nicotinamide adenine dinucleotide (NAD+) turnover numbers reaching 4230 and polymer-enlarged NADH reaching 80,000.
• Successfully produced chiral amino acids and alcohols with reduced cofactor dependency.

Conclusions:

• Reaction engineering significantly lowers cofactor costs in enzymatic synthesis of chiral molecules.
• Continuous processing with efficient cofactor recycling is key to economic biocatalysis.
• Advanced cofactor systems and reactor designs enable high-efficiency enzymatic production.