Antifouling activity of bacterial extracts associated with soft coral and macroalgae from the Red Sea

Abstract

In marine environments where biofouling occurs and has an impact on the maritime economy and environment, compounds that inhibit the attachment, growth and survival of microorganisms in a biofilm complex as well as settlement of larvae are considered potential antifouling compounds. In this study, the extracellular metabolites from two surface- associated bacteria isolated from soft coral and macroalga were evaluated for antibiofilm and antisettlement activity. The bacteria were identified using 16S rRNA gene sequencing, and the culture supernatant extract of each strain was evaluated for antibiofilm activity. The compounds present in the extracts were analysed using GC-MS. The two bacterial strains were identified as Bacillus licheniformis MBR1 and Vibrio alginolyticus MBR4 for the isolates from soft coral and macroalgae, respectively. The extracts inhibited the growth of biofilm-forming bacteria, biofilm formation and barnacle larval settlement. The GC-MS analysis of the extract detected the presence of compounds such as tetrapentacontane, octadecanoic acid, 2,3-dihydroxypropyl ester, hexadecanoic acid, 2-hydroxy1-(hydroxymethyl) ethyl ester and 17-pentatriacontene. The results of the study show that extracellular metabolites of the bacteria associated with marine organisms could be used as natural antifouling compounds to control biofouling.

Use of Alteromonas sp. Ni1-LEM Supernatant as a Cleaning Agent for Reverse-Osmosis Membranes (ROMs) from a Desalination Plant in Northern Chile Affected by Biofouling

“…Biological approaches have been proposed to solve this problem, such as the use of molecules with quorum-quenching activity, isolated enzymes, and the use of bacterial supernatants with mixes of enzymatic activities [ 13 , 14 , 15 ]. Quorum quenching aims to inhibit communication between bacteria, preventing their settlement, which generates fouling [ 15 , 16 ]; on the other hand, the use of isolated enzymes or bacterial supernatants is intended to be applied as a ROM-cleaning treatment, either by eliminating the bacterial component [ 17 , 18 ] or degrading the EPS that allows biological settlement [ 19 ].…”