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MICROBIAL PRODUCTION OF COMMERCIALLY IMPORTANT HYDROXYLATED COMPOUNDS FROM HALOAROMATICS

Objective

DEVELOPMENT OF A NEW PROCEDURE BASED ON ARTHROBACTER ENZYMES FOR PRODUCTION OF THE FOLLOWING IMPORTANT HYDROXYLATED PRODUCTS : 1,3,5,-TRIHYDROBENZENE, 4-HYDROXYPHENYLGLYCINE, TYROSINE, DOPA, 4-HYDROXYPHENYLACETATE, M- AND P- HYDROXYBENZALDEHYDE, M- AND P- HYDROXYACETOPHENON AND 3,5-DIHYDROXYBENZOIC ACID.
At present there are no readily available preparative chemical reactions for direct, specific hydroxylation of aromatic compounds on an industrial scale. Consequently, the hydroxyl group has to be introduced by an expensive series of reactions. Certain microorganisms can, however, specifically dehalogenate and hydroxylate aromatic compounds. Thus, it may be possible to use microogranisms as biocatalysts.

The microbial transformation of a range of chlorobenzoates, chlorophenols, chlorobenzenes and chloroactophenones was studied. Of these substrates, chlorobenzoates yielded hydroxylated metabolites most readily. 4-chlorobenzoate (4-CBA) was investigated in greatest detail. Several bacteria were isolated which transformed 4-CBA into the target metabolite, 4-hydroxybenzoate. The growth of these organisms and the rate of 4-CBA transformation was enhanced by sequential subculture. Uptake studies suggest an active mechanism for transport of the substrate into the cell.
The enzyme responsible for 4-CBA dehalogenation and hydroxylation was extracted from the organism, partially purified and characterized. It was found to convert all p-halogenated benzoates into 4-hydroxybenzoate.
CONVERSION OF HALOGEN SUBSTITUTED AROMATIC COMPOUNDS INTO THE CORRESPONDING HYDROXYLATED COMPOUNDS BY USING THE NEWLY DISCOVERED ARTHROBACTER DEHALOGENATING/HYDROXYLATING ENZYME.

IN PARTICULAR :
1. THE GROWTH OF ARTHROBACTER ON DIFFERENT HALOGENATED AROMATIC COMPOUNDS WILL BE ASSESSED IN BATCH OR CONTINUOUS CULTURE.

2. STUDY OF THE PRODUCTS PRODUCED BY NEW ANALYTICAL PROCEDURES (HIGH PRESSURE LIQUID CHROMATOGRAPHY AND GAZ CHROMATOGRAPHY).

3. ENRICHMENT OF APPROPRIATE STRAINS.

4. CHARACTERIZATION OF ENZYME ACTIVITY IN THE CELL FREE EXTRACT OF THE SELECTED MICROORGANISMS.

5. PURIFICATION AND OPTIMALIZATION OF THE SELECTED ENZYME ACTIVITY.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

CENTRE FOR APPLIED MICROBIOLOGY AND RESEARCH (CAMR)
Address
Porton Down
Salisbury
United Kingdom

Participants (1)

AGRICULTURAL UNIVERSITY
Netherlands
Address

Wageningen