A novel assay for rapid in vivo determination of phenotypic stability of recombinant ethanol-producing microorganisms
Bin Zhou, Gregory JO Martin, Neville B Parnment
BIORESOURCE TECHNOLOGY | ELSEVIER SCI LTD | Published : 2009
A rapid empirical assay is presented for assessing the phenotypic stability of continuous cultures of recombinant bacteria containing transposed pdc and adh genes for ethanol production. The method measures spectrophotometrically the rate of colour formation when cells oxidize added ethanol to acetaldehyde in the presence of Schiff's reagent. During chemostat cultures of the recombinant ethanologen Escherichia coli KO11 on 20 g/l glucose, assay activities were stable and high at ca 8 x 10(-4) DeltaOD(540)/(s.OD(550)), reflecting the high, stable ethanol yield (ca 95%). On 20 g/l and 50 g/l xylose, ethanol yields declined rapidly to about 60% and this was closely mirrored by the assay activit..View full abstract
We are grateful to Dr Geoff Dumsday for helpful discussions, to Professor L.O. Ingram for the gift of the E. coli KO11 strain and to the Australian Energy Research and Development Corporation for financial support.