N,N,N-trimethylglycinium → Ampicillin

Beteiligte Stoffe

Reaktionsschritte

Seed pre-cultures of strains containing pTrc99A or pLOI4319 were grown from plates using sealed culture tubes containing AM1 medium (20 g liter−1 xylose, 12.5 mg liter−1 ampicillin). MOPS buffer (100 mM; pH 7.0) was included for seed cultures of lactate strains XW068 and XW059. After incubation for 16 h, pre-inocula were diluted into 500-ml fermentation vessels containing 300 ml AM1 media (100 g liter−1 xylose, 1 mM betaine, 0.1 mM IPTG, 12.5 μg ml−1 ampicillin) to provide a starting density of 13.2 mg dcw. After 24 h growth, these seed cultures were used to provide a starting inoculum for batch fermentations (AM1 medium, 100 g liter−1 xylose, 12.5 μg ml−1 ampicillin, 0.1 mM IPTG, 13.2 mg dew initial density, and furfural). Fermentations were maintained at pH 6.5 (ethanol) or pH 7.0 (lactate) by the automatic addition of KOH as previously described (15, 29). Ethanol was measured using an Agilent 6890N gas chromatograph (Palo Alto, Calif.) equipped with flame ionization detectors and a 15-meter HP-Plot Q Megabore column. Furfural concentration was monitored using a Beckman DU spectrophotometer (27, 29). Organic acids and xylose were measured by high-performance liquid chromatography (15).

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