title: Antiadhesive activity of poly-hydroxy butyrate biopolymer from a marine Brevibacterium casei MSI04 against shrimp pathogenic vibrios.
abstract: BACKGROUND
  Vibrio pathogens are causative agents of mid-culture outbreaks, and early mortality syndrome and secondary aetiology of most dreadful viral outbreaks in shrimp aquaculture. Among the pathogenic vibrios group, Vibrio alginolyticus and V. harveyi are considered as the most significant ones in the grow-out ponds of giant black tiger shrimp Penaeus monodon in India. Use of antibiotics was banned in many countries due to the emergence of antibiotic-resistant strains and accumulation of residual antibiotics in harvested shrimp. There is an urgent need to consider the use of alternative antibiotics for the control of vibriosis in shrimp aquaculture. Biofilm formation is a pathogenic and/or establishment mechanism of Vibrio spp. This study aims to develop novel safe antibiofilm and/or antiadhesive process using PHB to contain vibrios outbreaks in shrimp aquaculture.
  
  
  RESULTS
  In this study a poly-hydroxy butyrate (PHB) polymer producing bacterium Brevibacterium casei MSI04 was isolated from a marine sponge Dendrilla nigra and production of PHB was optimized under submerged-fermentation (SmF) conditions. The effect of carbon, nitrogen and mineral sources on PHB production and enhanced production of PHB by response surface methods were demonstrated. The maximum PHB accumulation obtained was 6.74 g/L in the optimized media containing 25 g/L starch as carbon source, 96 h of incubation, 35°C and 3% NaCl. The highest antiadhesive activity upto 96% was recorded against V. vulnificus, and V. fischeri, followed by 92% against V. parahaemolyticus and V. alginolyticus and 88% inhibition was recorded against V. harveyi.
  
  
  CONCLUSIONS
  In this study, a thermostable biopolymer was chemically characterized as PHB based on 1HNMR spectra, FT-IR and GC-MS spectra. The NMR spectra revealed that the polymer was an isocratic homopolymer and it also confirmed that the compound was PHB. The antiadhesive activity of PHB was determined in microtitre plate assay and an effective concentration (EC) of PHB (200 μl containing 0.6 mg PHB) was confirmed by confocal laser scanning microscopic analysis of vibrio biofilm on pre-treated glass and polystyrene surfaces. This is a first report on anti-adhesive activity of PHB against prominent vibrio pathogens in shrimp aquaculture.
authors.forename: George Seghal
authors.initials: GS
authors.lastname: Kiran
authors.forename: Anuj Nishanth
authors.initials: AN
authors.lastname: Lipton
authors.forename: Sethu
authors.initials: S
authors.lastname: Priyadharshini
authors.forename: Kumar
authors.initials: K
authors.lastname: Anitha
authors.forename: Lucia Elizabeth Cruz
authors.initials: LE
authors.lastname: Suárez
authors.forename: Mariadhas Valan
authors.initials: MV
authors.lastname: Arasu
authors.forename: Ki Choon
authors.initials: KC
authors.lastname: Choi
authors.affiliation: Department of Microbiology, Pondicherry University, Puducherry 605 024, India. josephselvinss@gmail.com.
authors.forename: Joseph
authors.initials: J
authors.lastname: Selvin
authors.forename: Naif Abdullah
authors.initials: NA
authors.lastname: Al-Dhabi
mesh_terms: D000818:Animals; D001422:Bacterial Adhesion / Q000187:drug effects*; D001483:Base Sequence; D001704:Biopolymers / Q000494:pharmacology*; D001951:Brevibacterium / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D002087:Butyrates / Q000737:chemistry / Q000494:pharmacology*; D002152:Calorimetry, Differential Scanning; D003460:Crystallization; D005285:Fermentation / Q000187:drug effects; D006885:Hydroxybutyrates / Q000737:chemistry / Q000494:pharmacology*; D018613:Microscopy, Confocal; D033561:Penaeidae / Q000821:virology*; D010802:Phylogeny; D011091:Polyesters / Q000737:chemistry / Q000494:pharmacology*; D066244:Proton Magnetic Resonance Spectroscopy; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology*; D013696:Temperature; D014733:Vibrio / Q000187:drug effects*; D014961:X-Ray Diffraction; D000094122:Polyhydroxybutyrates
chemical_list: D001704:Biopolymers; D002087:Butyrates; D006885:Hydroxybutyrates; D011091:Polyesters; D012336:RNA, Ribosomal, 16S; C003182:poly-beta-hydroxybutyrate; D000094122:Polyhydroxybutyrates