Abstract
Pseudoalteromonas bacteria are known as potential bioactive metabolite producers. Because of the need to obtain natural molecules inhibiting the bacterial biofilms, we investigated the biofilm inhibitory activity of the marine bacterium Pseudoalteromonas sp. IIIA004 against the pioneer surface colonizer Roseovarius sp. VA014. The anti-biofilm activity from the culture supernatant of Pseudoalteromonas sp. IIIA004 (SN(IIIA004)) was characterized in microtiter plates (static conditions/polystyrene surface) and in flow cell chambers (dynamic conditions/glass surface). The Pseudoalteromonas exoproducts exhibited an inhibition of Roseovarius sp. VA014 biofilm formation as well as a strong biofilm dispersion, without affecting the bacterial growth. Microbial adhesion to solvent assays showed that SN(IIIA004) did not change the broad hydrophilic and acid character of the Roseovarius strain surface. Bioassay-guided purification using solid-phase extraction and C(18) reverse-phase-high-performance liquid chromatography (RP-HPLC) was performed from SN(IIIA004) to isolate the proteinaceous active compound against the biofilm formation. This new anti-biofilm low weight molecule (< 3kDa), named P(004), presented a wide spectrum of action on various bacterial biofilms, with 71% of sensitive strains including marine bacteria and human pathogens. Pseudoalteromonas sp. IIIA004 is a promising source of natural anti-biofilm compounds that combine several activities.