Isolation, identification and characterization of a new lipolytic Pseudomonas sp., strain AHD-1, from Tunisian soil

A novel, lipid-degrading bacterium (strain AHD-1) was isolated from soil regularly contaminated with washing-machine wastewater in Sfax, Tunisia. When this strain was grown in a medium containing 2% triacylglycerol, the hydrolysis products were found to be diacylglycerols, monoacylglycerols and free fatty acids. This strain was an aerobic, mesophilic, Gram-negative, motile, non-sporulating bacterium, capable of growing optimally at pH 7 and 27 degrees C. The predominant fatty acids were found to be C-16:1 omega 7c (31%), C-16:0(28.1%), C-18:1 omega 7c (16.3%) and C-17:0 (5.8%). Phylogenetic analysis of the 16S rRNA gene showed that this isolate is a new strain belonging to the genus Pseudomonas. Strain AHD-1 was found to be closely related to Pseudomonas azotoformans IAM 1603(T), Pseudomonas gessardii CIP 105469(T) and Pseudomonas libanensis CIP 105460(T) with 99.7%, 99.56% and 99.54% of similarity, respectively.