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Industrial Biotransformations

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Aspartase<br />

Escherichia coli<br />

3) Flow scheme<br />

Fig. 4.3.1.1 – 2<br />

4) Process parameters<br />

conversion: 99 %<br />

yield: 95 %<br />

selectivity: 96 %<br />

optical purity: >99.9 %<br />

chemical purity: 99 %<br />

reactor type: plug flow reactor<br />

reactor volume: 75 L<br />

residence time: 0.07 h<br />

space-time-yield: 3 kg · L –1. h –1<br />

down stream processing: precipitation<br />

enzyme consumption:<br />

company:<br />

t½ = 6 months<br />

BioCatalytics Inc., USA<br />

5) Product application<br />

● The product is used as a precursor for the synthesis of aspartame, an artificial sweetener (see<br />

page 373).<br />

● It is also used as an acidulant, as a food additive, in parenteral nutrition and as a chiral synthon<br />

in organic synthesis.<br />

6) Literature<br />

HOOC<br />

+NH 3<br />

E<br />

COOH<br />

HSO<br />

2 4<br />

pH 2.8<br />

precipitation<br />

● Rozzell, D. (1998) BioCatalytics, personal communication<br />

HOOC<br />

NH 2<br />

COOH<br />

EC 4.3.1.1<br />

495

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