Chiral amines are valuable compounds in the pharmaceutical industry. These valuable compounds have been made via organocatalysis, metallocatalysis but in the last two decades also via biocatalysis. Enzymes are highly selective, making them attractive catalysts to target chiral amine synthesis. The aim of this dissertation was to apply different biocatalytic pathways with oxidoreductases to synthesize chiral amines.

The rise of multi-drug resistant bacterial infections is a worldwide growing concern. Despite being one of the greatest medical advances of the 20th century, classical antibiotics are no longer effective against such organisms. Unfortunately, patients infected with drug-resistant bacteria are more likely to experience worse clinical outcomes, as well as have higher mortality rates. The bacterial respirasome is one of the most promising target spaces in the search for novel antibiotics, since many pathogenic organisms display unique respiratory adaptations: e.g., a change in the pathogens’ metabolism upon infection of the host. More importantly, these adaptations are often essential for the cell viability of the pathogen, what makes them excellent candidates for targeted inhibition.
These drug targets frequently are membrane-bound respiratory proteins. For this reason, they have a significantly different biochemical and biophysical behavior than that of cytoplasmic or other water-soluble proteins, and so they are notoriously difficult to study. Most remarkably, membrane proteins are amphipathic, interacting with the aqueous environment, but also surrounded by a highly hydrophobic environment. Lipid composition is extremely complex: lipids of different polarities, hydrophobic electron carriers, etc. Altogether, a multicomponent system that ought to be considered if we aim to design efficient drugs that will interact with these enzymes (i.e., inhibit them) in their native environments.

The utilisation of flow chemistry and immobilisation in biocatalysis is gaining attention as an attractive way to overcome some of the limitations commonly reported in traditional batch systems such as mass transfer restrictions, low productivities, substrate/product inhibition and safety, among others....

Enzymes are nature’s catalyst of choice for the highly selective and efficient coupling of carbohydrates. Enzymatic sugar coupling is a competitive technology for industrial glycosylation reactions, since chemical synthetic routes require extensive use of laborious protection group manipulations and often lack regio- and stereoselectivity.

Chiral amines are valuable compounds for their use as building blocks for pharmaceutical and fine chemical industries. Previously, chiral amines were made with metals as catalysts, but these are unsustainable and difficult to remove from the product. Organocatalysis is a sustainable alternative, but requires chiral ligands, which are costly. Over the last decade, biocatalytic methods have been developed as well. Our goal was to produce chiral amines with our designed bi-enzymatic cascades, containing an ene reductase and amine dehydrogenase. We produced and purified ene reductases and assayed the asymmetric reduction of our proposed substrate scope, consisting of unsaturated ketones and aldehydes. We also investigated the impact of multiple reaction conditions on these performances that are optimal for amine dehydrogenases. Starting with 10 mM of substrate, we obtained concentrations up to 9.7 mM amine. Also, we obtained 3-methylcyclohexylamine with an enantiomeric and diastereomeric excess up to 99%. Therefore, we conclude that this bi-enzymatic cascade is capable of producing chiral amines with both high enantiomeric and diastereomeric excess. Further research to perform cascades on a larger scale is recommended.