Enzymatic production acids

Fig. 6. Representative chemical reactions in the enzymatic production of amino acids.

Figure A8.4 Commercial process for the enzymatic production of L- and D-amino acids from N-acetyl-D,L-amino acids.

Recently, an environmentally benign and volume efficient process for enzymatic production of alkanolamides has been described where CALB catalyzes the amidation of lauric acid and ethanolamine in the absence of solvent, at 90 °C, to keep the reactants in a liquid state and to remove the water [18]. The enzyme was both very active and stable under the reaction conditions, with about half of the activity remaining after two weeks, obtaining the final amide with a 95% yield (Scheme 7.6). 

A homogeneous electrochemical enzyme immunoassay for 2,4-dinitrophenol-aminocaproic acid (DNP-ACA), has been developed based on antibody inhibition of enzyme conversion from the apo- to the holo- form Apoglucose oxidase was used as the enzyme label. This enzyme is inactive until binding of flavin adenine dinucleotide (FAD) to form the holoenzyme which is active. Hydrogen peroxide is the enzymatic product which is detected electrochemically. Because antibody bound apoenzyme cannot bind FAD, the production of HjOj is a measure of the concentration of free DNP-ACA in the sample. 

Schmidt, E., Ghisalba, O., Gygax, D. and Sedelmeier, G. (1992) Optimization of a process for the enzymatic production of fA )-2-hyroxy-4-phenyl butyric acid - an intermediate for inhibitors of angiotensin converting enzymes. Journal of Biotechnology, 24, 315-327. 

Bayer, T. (2004) 7-Aminocephalosporanic acid - chemical versus enzymatic production process, in Asymmetric Catalysis on Industrial Scale (2004), (eds H.-U. Blaser and E. Schmidt), Wiley-VCH Verlag GmbH, 117-130. 

As already mentioned, early attempts have been focused on the enzymatic production of lecithin in lecithin liposomes (Schmidli et al, 1991). The metabolic pathway was the so-called Salvage pathway, which converts glycerol-3-phosphate to phosphatidic acid, then diacylglycerol and hnally phosphatidylcholine. Production of the cell boundary from within corresponds to autopoiesis and would close the circle between minimal cell and the autopoietic view of cellular life. 

Lipases can be used in transferase reactions to exchange fatly acids in fats. This is of considerable interest to the food industry. The enzymatic production of cocoa butter substitutes is the most well-known example. Cocoa butter is the fat component in chocolate. It melts in the range between room temperature and body temperature because its triglyceride molecules contain certain combinatiorts of fatly acids. Natiual... 

Scheme 7.3 Enzymatic production of sulfur-containing flavour compounds in Allium species from amino acid flavour precursors, a S-Alk(en)yl cysteine sulfoxides and b (+)-S-l-propenyl cysteine sulfoxide (isoalliin) P-5 -Ppyridoxal-5 -phosphate...

Inhibition of Enzymatic Uric Acid Production in the Presence of Various Antioxidants at 80 pM Each in the Xanthine-Xanthine Oxidase System... 

In Leuconostoc oenos ML 34, we have shown oxaloacetic acid decarboxylation manometrically (6, 7, 8). We were also able to demonstate fluorometrically the enzymatic production of reduced NAD with malic acid as a substrate, but, of course, were unable to do so with oxaloacetic acid since no NADH could be formed from this substrate. It is likely that this oxaloacetic acid decarboxylation activity, as in Lactobacillus plantarum, is distinct from the activity causing the malic-lactic transition. It is also possible that oxaloacetic acid decarboxylation is caused by a malic enzyme. However, there is no verified NAD dependent malic oxidoreductase (decarboxylating) enzyme which does so (12). For example, Macrae (31) isolated a malic enzyme from cauliflower bud mitochondria which showed no activity with oxaloacetic acid. Similarly, Saz (32) isolated a malic enzyme from Ascaris lumbricoides which is also inactive toward oxaloacetic acid. True, the Enzyme Commission (12) lists an enzyme described as L-malate NAD oxidoreductase (decarboxylating) (E.C. 1.1.1.38) which is said to be capable of decarboxylating oxaloacetic acid, but its description dates back to the studies of Ochoa and his group, and we now feel this listing may be improper. 

In view of the current energy crisis, nonoil sources have to be considered for the production of liquid fuels and chemicals. The greatest renewable resource is cellulose, from which glucose can be produced either by enzymatic or acid hydrolysis. The glucose can be further processed to... 

The best-established method for the enzymatic production of L-amino acids is the separation of racemates of N-acetyl-DL-amino acids by acylase I (aminoacylase E.C. 3.5.1.14). N-Acetyl-L-amino acid is cleaved and yields L-amino acids whereas N-acetyl-D-amino acid does not react (Figure 7.10). 

Enzymatic production of L-amino acids 73 Centrifugal partition chromatographic reactor... 

J Kamphuis, WHJ Boesten, QB Broxterman, HFM Hermes, JAM van Balken, EM Meijer, HE Schoemaker. New developments in chemo-enzymatic production of amino acids. Adv Biochem Eng Biotechnol 42 133-186, 1990. 

Carlton, G. J. The Enzymatic Production of L-Aspartic Acid. In Biocatalytic Production of Amino Acids and Derivatives, Rozzell, J. D., Wagner, F. Eds., Hanser Publishers, 1992, p. 4. 

For the direct hydroxylation of N-heterocycles a microbial oxidation is most suitable. Lonza developed a process to produce 6-hydroxynicotinic acid on a 10 tonnes scale [5]. The enzymatic production is carried out in two-steps. Firstly, Achromobacter xylosoxydans LK1 biomass is produced, which possesses a highly... 

D-Amino acid oxidase is a highly stereoselective flavoenzyme the properties of which are described in detail in Section 13.5.1. The enzymatic production of... 

Bayer T. 7-aminocephalosporanic acid—chemical versus enzymatic production process. Asymmetric Catalysis Industrial Scale 2004 17-130. 

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