The petroleum-degrading bacteria Alcaligenes aquatilis strain YGD 2906 as a potential source of lipopeptide biosurfactant

Soummam river sediments were used to isolate a biosurfactant-producing and petroleum-degrading bacterium. The strain was identified as Alcaligenes aquatilis YGD 2906 using phenotypic characterization and 16S ribosomal RNA sequencing. The culture supernatant of the isolated strain showed no haemolytic activity had an oiled displacement of 23.66 ± 0.57 mm and Emulsification index (E₂₄) of 68.5% ± 0.5%. The biosurfactant produced in the minimal medium was extracted by acid precipitation and quantified gravimetrically, with a yield of 4.2 ± 0.01 g/L. The crude Biosurfactant was determinate by TLC and MALDI-TOF-MS as a lipopeptide with protein and lipid content of 8.49 ± 0.19% and 52.66 ± 1.16% respectively. This lipopeptide structure was confirmed by HPLC-MS/MS. This technique gave two main peak ranges which are typical of surfactins, iturins and fengycin. Tandem mass spectrometry was further used to elucidate the structure of the lipopeptide produced by the strain. The non-haemolytic nature of the lipopeptide produced by this strain offers opportunities for biomedical applications. Further work is needed to optimize production and analyze potential biomedical uses of this lipopeptide including antimicrobial properties.