CONICET | Buscador de Institutos y Recursos Humanos

Nowadays, finding novel, natural, and biocompatible compounds, with suitable interfacial/surface activity and low toxicity, continues to be a significantchallenge for the scientific community. At present, several reports demonstrate the successful use of foam fractionation techniques to scale up thebiosurfactant production processes. However, this field has received limited attention regarding the matter of Pseudomonas syringae strains.In this context, this work focuses on the lipopeptide (LP) production by P. syringae pv tabaci (PTA) in two bioreactors with different dimensions(TecBioV?TECNAL and LabFors?INFORS 4 HT) and their recovery using the foam fractionation. For this, glass foam fractionation columns were used andcoupled at the top of each bioreactor. In the fermentation experiments, cellular cultures were performed in 3 L of King Broth media (KB) at 28°C for 12-14 h. Previously, an experimental design was carried out to determine the optimal culture conditions, including factors such as agitation rate, andaeration level. The LP presence was evidenced by positive emulsifying activity (EA) against a control solvent. Additionally, the following parameters wereassessed: the volume of collected foam, LP yield and productivity, LP concentration within the foam, and the remaining KB. Finally, the LP percentagerecovery (R%) and LP enrichment in the foam (Enr) were calculated.It was feasible to recover LP by foam fractionation from both bioreactors. However, for LabFors, the LP presence in the remaining KB was evidenced by a+EA during the fermentation course. On the contrary, EA was null for TecBioV, suggesting low LP concentration in KB. These findings verified thatTecBioV exhibited nearly complete LP recovery within the condensed foam collected from the column. Additionally, some parameters were differentpossibly due to the geometry and culture differences between bioreactors. In this way, the ratio diameter/liquid height (D/H) is important to evaluatethe recovery of surfactant molecules. While the D/H LabFors ratio = 0.4 (1)indicates that the collected foam is more enriched with LP than the remaining KB. The TecBioV proved highly beneficial, as the recovery yield was almost100%. Finally, it is worth mentioning that, for both bioreactors, the collected foams showed an excellent AE against organic solvents/vegetable oils andremained stable at different extreme conditions.In summary, it was demonstrated that foam fractionation can be used as an integrative method for the LP production and recovery from PTA.Furthermore, it is important to highlight that LPs exhibit favorable physicochemical properties and a low toxicity, making them promising candidates for various industrial applications.

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