Degradation of Fatty Acids and Production of Biosurfactant as an Added Value, by a Bacterial Strain Pseudomonas aeruginosa DG2a Isolated from Aquaculture Wastewaters

Pepi, Milva; Focardi, Silvia; Lobianco, Arianna; Angelini, Diego L.; Borghini, Francesca; Focardi, Silvano E.

Degradation of Fatty Acids and Production of Biosurfactant as an Added Value, by a Bacterial Strain Pseudomonas aeruginosa DG2a Isolated from Aquaculture Wastewaters

2013

Aquaculture wastewaters, with oleic acid (C18:1 ω9) as the most representative contaminant fatty acid, were used as inoculum to perform enrichment cultures in mineral medium in the presence of oleic acid as the sole carbon and energy source, allowing isolation of four bacterial strains named DG1a, DG2a, DG1b and DG2b. 16S rRNA gene sequencing analysis assigned the four isolates to the species Pseudomonas aeruginosa. Among the isolates, P. aeruginosa strain DG2a showed degradation of fatty acids, including oleic acid (C18:1 ω9). The hydrophobicity features were investigated in strain DG2a, and a constitutive hydrophobicity in the bacterial cells was highlighted. The capability to produce biosurfactants by cells of the bacterial strain P. aeruginosa strain DG2a was evidenced both in the presence of oleic acid and of aquaculture wastewaters by revealing emulsifying activity, oil spreading tests, haemolytic and cetyltrimethylammonium bromide agar tests. Bacterial cultures containing raw biosurfactant were added to native wastewaters, showing a depletion of the oleic acid content. The use of the isolated bacterial strain P. aeruginosa strain DG2a and of the produced biosurfactant in bioremediation of aquaculture wastewaters is proposed, and the valorization of aquaculture wastewaters as raw material for biosurfactant production by using the isolate is moreover suggested.

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