A directed approach to the selection of bacteria with enhanced catabolic activity.
OBJECTIVE
This study was aimed at selecting catabolicly-improved bacteria by in vitro evolution using a specially designed fermentor system.


RESULTS
To facilitate this objective, genetic variation was induced by ultraviolet irradiation, and a selective pressure was subsequently exerted by gradual increases in the concentration of organic toxins. During a pilot experiment, a culture was forced to tolerate and catabolize a mixture of phenol and formaldehyde. The population developed a high resistance against formaldehyde and the specific degradation rate increased rapidly. Biochemical analysis of the mutants revealed an increase in the expression of enzymes involved in the pathway oxidizing formaldehyde.


CONCLUSIONS
The fermentor system described is, in general, suitable for the selection of bacteria with enhanced catabolic activities.


CONCLUSIONS
The procedure is an alternative to conventional genetic engineering, providing efficient and genetically stable strains suitable for applications in the field of environmental biotechnology.
Heesche-Wagner
K
K
Institute for Neurobiochemistry, AG Proteinchemistry, University of Witten/Herdecke, Germany.
Schwarz
T
T
Kaufmann
M
M
D001419:Bacteria / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D003470:Culture Media / Q000737:chemistry / Q000494:pharmacology; D005285:Fermentation; D005557:Formaldehyde / Q000378:metabolism; D019800:Phenol / Q000378:metabolism; D012641:Selection, Genetic
D003470:Culture Media; D005557:Formaldehyde; D019800:Phenol