Biodegradation of 2-methoxyethanol under aerobic conditions by bacterial isolate Pseudomonas sp. strain VB

Four bacterial isolates from four different environmental samples (agricultural soil, compost soil and sewage sludge- anaerobic and aerobic wastewaters) were screened for their ability to mineralize 2-methoxyethanol under aerobic conditions. Isolate from anaerobic sewage wastewater was most efficient with an average of 48.6mmol/day mineralisation capacity. Morphological, physiological, biochemical and molecular characterization of the isolate showed that the strain, designated VB is of the genus

Pseudomonas

. 16S rRNA sequence analysis showed that the organism is related to

Pseudomonas putida

at 99.9% and

Pseudomonas plecoglossicida

at 99.8% similarity level. It is related to members of the genus

Pseudomomas

belonging to the rRNA group 1 within the gamma (γ)

Proteobacteria

. The G+C content 64.5±0.8mol% is within the range characteristic of the genus

Pseudomonas

. In a time course experiment

Pseudomonas

sp. strain VB was grown in 2-methoxyethanol, ethylene glycol, glycollate, glyoxylate, oxalate and methanol. Strain VB was able to utilize all proposed intermediates except methanol. Comparable growth characteristics of

Pseudomonas

sp. strain VB grown in 2- methoxyethanol and proposed intermediates showed significant molar growth yields. These results indicate that ethylene glycol, glycollate, glyoxylate and oxalate might be intermediates in the degradation pathway of 2-methoxyethanol. Thus a reaction sequence: 2-methoxyethanol → ethylene glycol → glycollate → glyoxylate → oxalate is been proposed in this study.