title: Antioxidant and antimicrobial potential of the Bifurcaria bifurcata epiphytic bacteria.
abstract: Surface-associated marine bacteria are an interesting source of new secondary metabolites. The aim of this study was the isolation and identification of epiphytic bacteria from the marine brown alga, Bifurcaria bifurcata, and the evaluation of the antioxidant and antimicrobial activity of bacteria extracts. The identification of epiphytic bacteria was determined by 16S rRNA gene sequencing. Bacteria extracts were obtained with methanol and dichloromethane (1:1) extraction. The antioxidant activity of extracts was performed by quantification of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and oxygen radical absorbance capacity (ORAC). Antimicrobial activities were evaluated against Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Salmonella enteritidis, Staphylococcus aureus, Saccharomyces cerevisiae and Candida albicans. A total of 39 Bifurcaria bifurcata-associated bacteria were isolated and 33 were identified as Vibrio sp. (48.72%), Alteromonas sp. (12.82%), Shewanella sp. (12.26%), Serratia sp. (2.56%), Citricoccus sp. (2.56%), Cellulophaga sp. (2.56%), Ruegeria sp. (2.56%) and Staphylococcus sp. (2.56%). Six (15.38%) of the 39 bacteria Bifurcaria bifurcata-associated bacteria presented less than a 90% Basic Local Alignment Search Tool (BLAST) match, and some of those could be new. The highest antioxidant activity and antimicrobial activity (against B. subtilis) was exhibited by strain 16 (Shewanella sp.). Several strains also presented high antimicrobial activity against S. aureus, mainly belonging to Alteromonas sp. and Vibrio sp. There were no positive results against fungi and Gram-negative bacteria. Bifurcaria bifurcata epiphytic bacteria were revealed to be excellent sources of natural antioxidant and antimicrobial compounds.
authors.affiliation: Marine Resources Research Group (GIRM), School of Tourism and Maritime Technology (ESTM), Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal. andre.horta@ipleiria.pt.
authors.forename: André
authors.initials: A
authors.lastname: Horta
authors.affiliation: Marine Resources Research Group (GIRM), School of Tourism and Maritime Technology (ESTM), Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal. susete.pinteus@ipleiria.pt.
authors.forename: Susete
authors.initials: S
authors.lastname: Pinteus
authors.affiliation: Marine Resources Research Group (GIRM), School of Tourism and Maritime Technology (ESTM), Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal. celso.alves@ipleiria.pt.
authors.forename: Celso
authors.initials: C
authors.lastname: Alves
authors.affiliation: Marine Resources Research Group (GIRM), School of Tourism and Maritime Technology (ESTM), Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal. nadia.fino@ipleiria.pt.
authors.forename: Nádia
authors.initials: N
authors.lastname: Fino
authors.affiliation: Marine Resources Research Group (GIRM), School of Tourism and Maritime Technology (ESTM), Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal. joana.m.silva@ipleiria.pt.
authors.forename: Joana
authors.initials: J
authors.lastname: Silva
authors.affiliation: Higher School of Agricultural Engineering (ETSEA), University of Lleida, E-25003 Lleida, Spain. sara_lofer@hotmail.com.
authors.forename: Sara
authors.initials: S
authors.lastname: Fernandez
authors.affiliation: Marine Resources Research Group (GIRM), School of Tourism and Maritime Technology (ESTM), Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal. arodrigues@ipleiria.pt.
authors.forename: Américo
authors.initials: A
authors.lastname: Rodrigues
authors.affiliation: Marine Resources Research Group (GIRM), School of Tourism and Maritime Technology (ESTM), Polytechnic Institute of Leiria, 2520-641 Peniche, Portugal. rpedrosa@ipleiria.pt.
authors.forename: Rui
authors.initials: R
authors.lastname: Pedrosa
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry* / Q000302:isolation & purification; D000975:Antioxidants / Q000737:chemistry* / Q000302:isolation & purification; D001412:Bacillus subtilis / Q000187:drug effects; D001419:Bacteria / Q000737:chemistry* / Q000302:isolation & purification; D044822:Biodiversity; D001713:Biphenyl Compounds / Q000737:chemistry; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D016166:Free Radical Scavengers / Q000737:chemistry / Q000494:pharmacology; D005609:Free Radicals / Q000737:chemistry; D008826:Microbial Sensitivity Tests; D000459:Phaeophyceae / Q000382:microbiology*; D010636:Phenols / Q000737:chemistry; D010851:Picrates / Q000737:chemistry; D012623:Seawater / Q000382:microbiology; D013211:Staphylococcus aureus / Q000187:drug effects; D014871:Water Microbiology
chemical_list: D000890:Anti-Infective Agents; D000975:Antioxidants; D001713:Biphenyl Compounds; D004269:DNA, Bacterial; D016166:Free Radical Scavengers; D005609:Free Radicals; D010636:Phenols; D010851:Picrates; C004931:1,1-diphenyl-2-picrylhydrazyl