Naslov
Alternative Approach for High Energy Extensive Pyruvate Production: E. coli Based Process Development

Autori
Zelić, Bruno ; Gerharz, Tanja ; Bott, Michael ; Wandrey, Christian ; Takors, Ralf

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts / Marquardt, Wolfgang ; Wagner, Wolfram - Weinheim : Wiley-VCH, 2002

Skup
GVC/DECHEMA Jahrestagunegen 2002 (20. Jahrestagungen der Biotechnologen)

Mjesto i datum
Wiesbaden, Njemačka, 11.06.2002. - 13.06.2002

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
E. coli; pyruvate; process development

Sažetak
Introduction: The commercial demand for pyruvic acid is expanding because of its use as an effective starting material for the synthesis of many drugs, agrochemicals and nowadays in food industry as a fat burner. It is also a valuable substrate for the enzymatic production of amino acids such as L-tryptophane, L-tyrosine and L-dihydroxyphenylalanine (L-DOPA). The main goal in this project is the development of a pyruvate production process from glucose with a high molar pyruvate/glucose yield (approaching 2 mol pyruvate / mol glucose) and space-time yield using a recombinant Escherichia coli strain. This strain is completely blocked in its ability to convert pyruvate in acetyl-CoA or acetate, resulting in acetate-auxotrophy during growth in glucose minimal medium. Methods: Due to the strain genotype, acetate availability was assumed to represent a key fermentation variable. Experimental studies identified a &#8216 ; ; ; simple&#8217 ; ; ; correlation between acetate consumption rate (ACR) and CO2 production rate (CTR), interestingly, with an optimum equal molar ratio. Therefore, CTR (calculated on-line by CO2 and O2 exhaust gas analysis) was used for on-line calculation and regulation of the acetate feed. By changing the parameter f, acetate limiting, saturating and accumulating conditions could be established. Additionally, glucose concentrations were controlled on-line. Controlling acetate and glucose, a series of lab-scale experiments were performed to optimize molar yield pyruvate/glucose, space time yield and pyruvate final concentration. Additionally, measurements of intra-cellular pyruvate concentrations by LC-MS were done. Results: At optimal process conditions a final pyruvate concentration higher than 500 mM (44 g/L), a space-time yield of 24.7 mmol/L/h and a molar yield pyruvate/glucose of 0.80 mol/mol were achieved. Pyruvate export through the cytoplasmic membrane is by active transport, because the extra-cellular pyruvate concentration was 102 fold higher then the intra-cellular one during the entire process time.

Izvorni jezik
Engleski

Znanstvena područja
Biotehnologija

POVEZANOST RADA