Marine derived bacteria from restinga ecosystems as a platform for antibiofilm agents and next-generation postbiotics and probiotics (NGPPs)

Abstract

Marine derived bacteria are a rich source of bioactive compounds that have the potential to be used in the control of infectious diseases and as Next-Generation Postbiotics and Probiotics (NGPPs). However, their antibiofilm activity against major human pathogens remains understudied. This study isolated 211 bacterial strains from Restinga ecosystems along the Southern Coast of Rio Grande do Sul, Brazil and screened them for postbiotics and probiotic traits, such as safety, stress tolerance, and antibiotic susceptibility. A subset of the 65 isolates was used for cultivation of 65 supernatants in mono- and 65 supernatants in co-culture conditions in different media to evaluate antibacterial and antibiofilm activities. About 5%–7% of the supernatants inhibited biofilm formation by at least 50% against Pseudomonas aeruginosa and Staphylococcus aureus. Co-culture enhanced the antibacterial activity against P. aeruginosa . Extraction methods strongly influenced bioactivity outcomes. Conventional extraction yielded antibiofilm activity (40%–80%) against S. aureus , though this was often accompanied by increased planktonic growth. Low or no activity was observed against P. aeruginosa . Notably, solid-phase extraction (SPE) enabled the recovery of highly active fractions. Among the isolates, strain 6, identified as Pseudomonas sputi MaRe06, exhibited the most promising profile by combining strong antibiofilm activity with the most apolar fraction (F100) against S. aureus (80% inhibition at 300 μg/mL) and robust tolerance to in vitro gastrointestinal conditions. These findings highlight the Restinga Ecosystems as a valuable source of bioactive metabolites and support the development of novel antibiofilm agents and NGPPs from marine bacteria.