Chapter 1. Provides an Introduction to dioxygenases, their Involvement In aromatic degradation ant formation of chiral c/s-dlols. The toluene dioxygenase (TOO, mechanism of action, amino acids In the active site and their blocatalytlc activity towards phenolic metabolites are Introduced. Application: of these chiral c/s-dlol metabolites obtained by TDO-catalysed oxidations are exemplified. Chapter 2. Whole cell biotransformations of meta-methoxyphenol using the constitutive mutanl Pseudomonas putlda UV4 strain expressing TOO and Inducer recombinant Escherichia coll (pCL-4T strain exclusively expressing TDO was conducted. Scale-up blotransformatlon of meta methoxyphenol was also discussed. The metabolites were Isolated and characterised fully by uslnf X-ray crystallography, NMR spectroscopy, GC- and LC- mass spectrometry. Add- and base chemocatalysed reactions of the major cydohexenone c/s-dlol metabolites were also studied. Chapter 3. Similar methods were used for the blotransformatlon of ort/io-methoxyphenol (gualacol, using P. putlda UV4 and Escherichia coll (pCL-4T) strains, where the metabolites were Isolated and characterised fully. In-depth stability, conformational and configurational studies were conducted on the isolated metabolites. Results for blotransformatlon of para-methoxyphenol were also presented. Biosynthetic pathways were proposed and discussed, for the formation of novel chiral metabolites derived from phenolic substrates. Chapter 4. Having established the structure and stereochemistry of metabolites derived from methoxyphenols (Chapter 2 and 3), studies of whole cell blotransformatlons with a series of substituted anilines and their corresponding phenol counterparts using P. putlda UV4 and E.coll (pCL-4T) whole cells were described. Blotransformatlon of a series of other substituted phenols, catechols and hydroquinones using both these strains were also attempted. Detection and confirmation of the presence of TDO-catalysed metabolites was examined by a combination of GC-MS and LC-MS analytical methods. Chapter 5. Contains prellmarary computational docking studies and elaborates on the future prospects of dioxygenase-catalysed studies. Chapter 6. Methodology, experimental and computational docking results.