MARTIN SCHÜRMANN, MONIKA MÜLLER
InnoSyn B.V., Geleen, The Netherlands

Abstract

The industrial application of enzymes requiring complex biochemical co-factors or co-substrates has progressed significantly in the past decades. This article spot-lights the developments in the biocatalytic supply and recycling of selected co-substrates such as NAD(P)H, NAD(P)+, ATP, UDP-glucose and 2-ketoglutarate in academia and industry.
Their application has been hampered by limited availability, stability and high price. Biocatalytic supply and recycling was first implemented for reductions with reduced NAD(P)H resulting in numerous industrial applications. Here we highlight more recent developments that enable the oxidative recycling of NAD(P)+ for oxidations with oxygen, (cost-)efficient and stable phosphoenol pyruvate formulation for ATP regeneration from ADP, UDP-glucose supply and recycling from UDP and sucrose for selective glycosylations as well as 2-ketoglutarate supply from L-glutamate for hydroxylations.

Enzymes catalyse chemical reactions with astonishingly high turnover frequencies and rate enhancements over the uncatalyzed reactions making them very attractive catalysts for the organic synthesis of pharma, fine, specialty and to certain extent also bulk chemicals. As biocatalysts they achieve turnover frequencies or kcat values of up to several millions per second (or mol product/mol biocatalyst per second) like catalase and carbonic anhydrase (1, 2) and rate enhancements over the uncatalyzed reaction of more than a billion-fold as certain decarboxylases and nucle(osid)ases do (2). These rate enhancements and their unrivalled chemo-, regio- and enantioselectivity make enzymes a valuable tool in chemical industry (acrylic acid from acrylonitrile by nitrile hydratase) but also in food industry (e.g. glucose fructose syrups with glucose isomerase). Especially for the production of pharma but also fine chemicals enzymes – including co-factor and co-substrate dependent ones - are routinely applied on industrial scale (Table 1).

Chemically relatively simple reactions like lipase catalysed interconversions of fats and oils or enantioselective ester hydrolyses or sy ...