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The genes encoding polyphosphate kinase (PPK) and exopolyphosphatase (PPX) were isolated from Pseudomonas aeruginosa 8830 to study polyphosphate metabolism and clarify the function of polyphosphate in the microorganism. In contrast to Escherichia coli, the ppk and ppx genes in P aeruginosa are transcribed divergently and no coregulation between their expression was shown by a study of the two promoters. A residual low PPK activity was detected in the mutant, representing a separate mechanism of polyP synthesis.

A study was conducted to determine and describe the tftCD gene to characterize the upper portion of the aromatic compound 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) pathway in Burkholderia cepacia. Plasmid-preparative columns were utilized to perform a large-scale purification of cosmids while agarose plugs with intact chromosomal DNA were determined from overnight cultures. Results showed that the genes encoding the 2,4,5-T oxygenase, tftAB, were on replicon IV.

The enzyme hydroxyquinol 1,2-dioxygenase and maleylacetate reductase have been purified from Escherichia coli cells expressing the Burkholderia cepacia AC1100 tftH gene and tftE gene, respectively. The two enzymes catalyze the formation of 3-oxoadipate from hydroxyquinol. Genetic studies reveal that these enzymes bring about degradation of 2,4,5-trichlorophenoxyacetic acid. Hydroxyquinol 1,2-dioxygenase is a dimeric molecule of 68 kDa.

The Burkholderia cepacia AC1100 oxygenase (TftAB) converts 2,4,5-trichlorophenoxyacetic acid to 2,4,5-trichlorophenol and many other chlorinated aromatic phenoxyacetates to their phenolic derivatives. The rate of substrate consumption by TftAB depends upon the degree of substrate chlorination, chlorines position and phenoxy group. There is a mechanistic similarity between TftAB and TfdA of Alcaligenes eutrophus. Escherichia coli and Burkholderia cepacia expresses the promoter cloned upstream of the beta-galactosidase gene and show beta-galactosidase activity.

Sequencing of the 2.7-kb Sst-XbaI DNA fragment involved in the conversion of 2,4,5-T, the carbon source of Pseudomonas cepacia, to 2,4,5-trichlorophenol, indicates the presence of two open reading frames (ORFs) in the fragment. The ORFs are homologous to the BenA and BenB and XylX and XylX proteins and other biodegradative dioxygenase complexes in their amino acid sequences. Pulse-labeling experiments enable the identification of the directions of transcription of these genes and the number and sizes of the polypeptide synthesized. The enzymes encoded by the two ORFs, TftA1 and TftA2, exhibit a relaxed substrate specificity.

High-level expression of alginate lyase in the 8830 mucoid strain induces degradation of alginate and increased cell detachment of Pseudomonas aeruginosa cells. The degradation occurs when alginate lyase is induced in the early or late stages of cell growth. Alginate lyase expressed from a modulated promoter sequence, causes improved cell sloughing due to alginate degradation process.

The activity of an alginate promoter of Pseudomonas aeruginosa was monitored by a reporter gene technology. Chromogenic and fluorogenic substrates from beta-galactosidase were used to demonstrate reporter activity. Fourier transform infrared spectroscopy, uronic acid accumulation and alginate- specific enzyme-linked immunosorbent assay measured the correlation between gene-up expression and alginate biosynthesis. The activation of the specific gene was demonstrated.