Broad volumetric productivity

A direct comparison of catalysis of olefin epoxidation with a homogeneous chemical catalyst (Mn salen), an enzyme (CPO), and an antibody resulted in sufficiently high enantioselectivity for all three catalysts, a higher turnover number for the enzyme, and a slightly higher substrate/catalyst ratio for the homogenous catalyst. Criteria for comparison should be quantitative and include catalyst lifetime as well as volumetric productivities, but have been found to depend on the different needs of laboratory synthetic chemists, who need a broadly specific catalyst quickly, versus those of process chemists, who often control catalyst availability and can allow narrow specificity (provided their substrate is accepted) but need high productivity. 

For continuous production of L-p-fluorophenylalanine, a typical set of operating conditions is shown in Table 12.7-2. L-Aspartate is used at a 10 % molar excess to the starting 2-ketoacid. The cofactor pyridoxal phosphate is added to the reaction mixture to achieve a final concentration of 0.1 mM. The initial pH of the feed solution is 7.2. Mg2+ ion was used to accelerate the decarboxylation of oxaloacetate to pyruvate. The reaction was maintained with a temperature range of37-40 °C. Under these conditions using an immobilized broad-range aminotransferase, the volumetric productivity of the reactor for the production of L-phenylalanine at 85% conversion was 20 gL 1h 1. 

SuDsU ate oxygenation and mechanism ofsMMO catalysis After a broad substrate specificity of the sMMO system was discovered by Colby et al in 1977, a number of reviews and articles which include a possibility of sMMO as industrial biocatalysts have appeared [15]. Although significant works have been carried out to use methanotrophs for industrial purpose and many patents have been issued since 1981 [67], no process involving a sMMO system has been commercialized so far. This is due to the low volumetric productivity (< 5g of product/liter/hour) of the biocatalytic process in an... 

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