Strains Of Marine Bacteria Research Articles

Precipitation of barite by marine bacteria: A possible mechanism for marine barite formation

Barite (BaSO 4 ) is found throughout the ocean, yet seawater is undersaturated with respect to barite, and organisms that could account for the abundance of barite have not yet been identifi ed. The mechanism for barite formation in seawater is not fully understood. Here we show that marine bacteria have the ability to precipitate barite through a metabolically mediated biomineralization process. We precipitated barite in laboratory experiments in the presence of several strains of marine bacteria grown on yeast media enriched with barium (Ba); barite did not precipitate under identical conditions in killed-bacteria controls. The crystals develop from amorphous, phosphorous-rich spherical precursors with fi brous internal textures, common in bacterial mineral precipitation. Bacterial mediation of barite precipitation can explain the distribution of barite in the water column and the occurrence of barite crystals in organic-rich sinking aggregates where bacteria are concentrated. This fi nding has implications for the use of barite and Ba proxies in paleoceanographic research.

Isolation of marine bacteria highly resistant to mercury and their bioaccumulation process

The marine bacteria strains S1, S2 and S3, were isolated on seawater culturing medium containing Hg2+, Cd2+, Cr6+ or Ni2+ at concentrations of 20mgL−1 and more. The isolates showed tolerance to these heavy metals. S1 grew in the presence of 120mgL−1 of Hg2+ and accumulated Hg2+ at pH 4–10. For the effect of co-existing cations on bioaccumulation of target metal, it was found that the effect depended on not only the variety and initial concentration of co-existing ions, but also the initial concentration of target metal and biomass dosage. A new parameter, the ratio of remaining bioaccumulation capacity (RRBC) of biomass, was therefore defined to evaluate such effect. Furthermore, the mechanism evaluation revealed that S1 bound about 70% Hg2+ on the cell surface, and carboxyl group played an important role in Hg2+ binding.

Distribution of α-N-acetylgalactosaminidases among marine bacteria of the phylum Bacteroidetes, epiphytes of marine algae of the Seas of Okhotsk and Japan

Occurrence of α-N-acetylgalactosaminidases among 177 strains of marine bacteria of the phylum Bacteroidetes, epiphytes of marine algae growing on the littoral of the Seas of Okhotsk and Japan, was studied. About 36% of the isolates studied contained α-N-acetylgalactosaminidase. All of the bacteria of the genus Arenibacter (species A. latericius, A. certesii, and A. palladensis), irrespective of the source of isolation, synthesized this enzyme. The greatest number of α-N-acetylgalactosaminidase producers was found among the isolates from the algae Neosiphonia japonica, Acrosiphonia sonderi, and Ulva fenestrata sampled in the Cove of Trinity, Posyet Bay, the Sea of Japan. These were mainly bacteria of the genera Zobellia (50%) and Maribacter (58%). Among the epibionts studied, the bacteria Arenibacter latericius KMM 3523, an epiphyte of the brown alga Chorda filum from the Sea of Okhotsk, and Cellulophaga sp. KMM 6488, an epiphyte of the green alga Acrosiphonia sonderi from the Sea of Japan, were marked as the most promising sources of the enzyme. The results of this study showed that aerobic nonpathogenic marine Bacteroidetes, algal associants not requiring special cultivation conditions, are the promising, economical, and ecologically pure sources of unique and biotechnologically significant α-N-acetylgalactosaminidases.

Design and field application of a UV-LED based optical fiber biofilm sensor

Detecting changes in the formation dynamics of biofilms stemming from bacteria and unicellular microorganisms in their natural environment is of prime interest for biological, ecological as well as anti-fouling technology research. We developed a robust optical fiber-based biofilm sensor ready to be applied in natural aquatic environments for on-line, in situ and non-destructive monitoring of large-area biofilms. The device is based on the detection of the natural fluorescence of microorganisms constituting the biofilm. Basically, the intrinsic fluorescence of the amino acid tryptophan is excited at a wavelength of λ=280nm and detected at λ=350nm utilising a numerically optimized sensor head equipped with a UV-LED light source and optical fiber bundles for efficient fluorescence light collection. Calibration was carried out with tryptophan solutions and two characteristic marine bacteria strains revealing linear signal response, satisfactory background suppression, wide dynamic range, and an experimental detection limit of 4×103cells/cm2. Successful field experiments in the Baltic Sea accomplished over a period of twenty-one days provided for the first time continuous observation of biofilm formation dynamics in a natural habitat. Starting from the first adhering bacteria, the measurement yielded the characteristic three phases of biofilm formation up to a fully developed biofilm. The sensor system holds potential for applications in aquatic sciences including deep sea research and, after further miniaturisation, in the industrial and biomedical field.

D N / d S does not show positive selection drives separation of polar‐tropical SAR11 populations

Mol Syst Biol. 8: 625 Large‐scale sequencing of environmental microorganisms (including genomes, metagenomes, and metatranscriptomes) now allows researchers to apply sequence‐based evolutionary genetics approaches to microbial ecology questions, including studying how microbes adapt to a diversity of natural environments. There is, however, a danger for misapplication and misinterpretation if the caveats and limitations of these evolutionary methods are not fully appreciated. Here, we highlight an example of such problems in an evolutionary analysis of potential positive selection within strains of SAR11 marine bacteria (Brown et al , 2012). We feel that these issues deserve wider recognition, particularly as evolutionary approaches become more widespread among environmental microbiologists. In the vast majority of genes, the ratio (ω) of non‐synonymous substitutions per non‐synonymous site ( d N ) to synonymous substitutions per synonymous site ( d S ) is 1, then this may be indicative of positive selection favoring amino‐acid replacements (Hughes and Nei, 1988, Hughes, 1999). If ω is not statistically different from 1, then there is evidence for neither purifying nor positive selection. Positive selection is not the only factor that can cause ω to be >1; since ω is a ratio, an unusually high ω value may indicate either an unusually high d N or an unusually low d S . For example, purifying selection on synonymous mutations can lead to a low d S and thus high ω (Parmley and Hurst, 2007). Approaches for calculating d S and d N can be classified into two categories, based on whether the underlying nucleotide evolutionary model takes into account the base/codon frequency bias (Supplementary Table S1; Zhang et al , 2006). For instance, the Yang and Nielsen method (YN00) considers the base/codon …

Booster biocides and microfouling

Antifouling (AF) paints are used to prevent the attachment of living organisms to the submerged surfaces of ships, boats and aquatic structures, usually by the release of biocides. Apart from copper, organic booster biocides are the main active components in AF paints, but their use can have a negative impact on the marine environment. The direct effects of biocides on marine bacteria are poorly known. This work investigates the impact of two biocides, viz. diuron and tolylfluanid, on the growth and the viability of marine microorganisms and on their ability to form biofilms. The biocides in solution were found to inhibit growth of two strains of marine bacteria, viz. Pseudoalteromonas and Vibrio vulnificus, at a high concentration (1000 μg ml−1), but only a small effect on viability was observed. Confocal laser scanning microscopy (CLSM) showed that the booster biocides decreased biofilm formation by both bacteria. At a concentration of 10 μg ml−1, the biocides inhibited cell attachment and reduced biofilm thickness on glass surfaces. The percentage of live cells in the biofilms was also reduced. The effect of the biocides on two diatoms, Fragilaria pinnata and Cylindrotheca closterium, was also evaluated in terms of growth rate, biomass, chlorophyll a content and attachment to glass. The results demonstrate that diuron and tolylfluanid are more active against diatoms than bacteria.

Bacterias marinas productoras de compuestos antibacterianos aisladas a partir de invertebrados intermareales

Prospective sampling activities of intertidal invertebrates in the Ancon Bay (Lima, Peru) were done in order to select marine bacteria producing antimicrobial substances. The study included the isolation of bacteria in marine agar, in vitro antimicrobial susceptibility testing and electronic microscopic observations. We report the isolation, phenotypical characterization and antimicrobial properties of 10 strains of marine bacteria including the genus Vibrio, Pseudomonas, and Flavobacterium, and the order Actinomycetae that inhibit human pathogens. The results indicate that the marine invertebrates would be sources of bacteria producing antibiotic substances.

A rapid method for the isolation of eicosapentaenoic acid-producing marine bacteria

Bacterial production of long chain polyunsaturated fatty acids (LC-PUFAs) is a promising biotechnological approach for the mass production of these valuable compounds, but extensive screening is currently needed to select a strain that meets industrial requirements. A method was developed for the rapid screening and isolation of eicosapentaenoic acid (EPA)-producing marine bacteria from mixed cultures using the dye 2,3,5-triphenyltetrazolium chloride (TTC). The method was first validated using two bacteria from the Shewanella genus, S. gelidimarina (known to contain EPA) and S. fidelis (known not to contain EPA), and subsequently applied to a range of bacterial samples collected from seven randomly selected New Zealand fish species. By incorporating TTC in both solid and liquid state fermentation treatments, a clear association between the reduction of TTC to the red-coloured triphenyl formazan (TF) and the presence of EPA within Gram-negative bacteria was confirmed. Incubation in 0.1% w/v TTC was optimal for colour response and cell growth in agar plates and liquid cultures. Bacteria that produce EPA reduced TTC to TF, but a number of non-EPA-producing bacteria also showed this capacity. By conducting a subsequent Gram staining, all EPA-producing strains were revealed to be G (−) rod bacteria while the non-producing ones were all G (+) cocci. The fatty acid methyl esters of the isolated bacteria that reduced TTC to TF were analysed using gas chromatography–mass spectrometry and the content of EPA was confirmed by gas chromatography. From a pool of 2.0 × 10 8 CFU/ml, this method allowed the rapid isolation of 16 bacteria capable of producing EPA. This new approach significantly reduces the number of samples submitted for GC analysis and therefore the time, effort and cost of screening and isolating strains of EPA-producing marine bacteria.

Estudio químico y evaluación de la actividad antifouling del octocoral caribeño Eunicea laciniata

The bioassay guided purification of the octocoral Eunicea laciniata organic extract, collected at Santa Marta bay, Colombia, allowed the isolation of the new compound (-)-3β-pregna-5,20-dienyl-β-D-arabinopyranoside (1), along with the known compounds 1(S*),11(R*)-dolabell-3(E),7(E),12(18)-triene (2), 13-keto-1(S),11(R)-dolabell-3(E ),7(E),12(18)-triene (3), cholest- 5,22-dien-3β-ol (4), cholesterol (5), y brassicasterol (6). The structure and absolute configuration of 1 was determined on based spectroscopic analyses (NMR and CD). The extract showed antifouling activity against five strains of marine bacteria associated to heavy fouled surfaces. Also showed activity against the cypris of the cosmopolitan barnacle Balanus amphitrite, and low toxicity in Artemia salina test.

Aliagarivorans marinus gen. nov., sp. nov. and Aliagarivorans taiwanensis sp. nov., facultatively anaerobic marine bacteria capable of agar degradation

Two agarolytic strains of Gram-negative, heterotrophic, facultatively anaerobic, marine bacteria, designated AAM1T and AAT1T, were isolated from seawater samples collected in the shallow coastal region of An-Ping Harbour, Tainan, Taiwan. Cells grown in broth cultures were straight rods that were motile by means of a single polar flagellum. The two isolates required NaCl for growth and grew optimally at about 25-30 degrees C, in 2-4% NaCl and at pH 8. They grew aerobically and could achieve anaerobic growth by fermenting D-glucose or other sugars. The major isoprenoid quinone was Q-8 (79.8-92.0%) and the major cellular fatty acids were summed feature 3 (C16:1omega7c and/or iso-C15:0 2-OH; 26.4-35.6%), C18:1omega7c (27.1-31.4%) and C16:0 (14.8-16.3%) in the two strains. Strains AAM1T and AAT1T had DNA G+C contents of 52.9 and 52.4 mol%, respectively. The two strains had a 16S rRNA gene sequence similarity of 98.6% and shared 84.9-92.4% sequence similarity with the type strains of Agarivorans albus (91.2-92.4%), eight Alteromonas species (84.9-87.1%), two Aestuariibacter species (86.0-87.0%), Bowmanella denitrificans (86.1-86.7%), eight Glaciecola species (85.0-87.9%) and Salinimonas chungwhensis (85.9-86.1%). Despite their high sequence similarity, strains AAM1T and AAT1T had a DNA-DNA relatedness value of only 4.5%. The data obtained from these polyphasic taxonomic studies revealed that the two agarolytic isolates could be classified as representatives of two novel species in a new genus, Aliagarivorans gen. nov., with Aliagarivorans marinus sp. nov. [type strain is AAM1T (=BCRC 17888T=JCM 15522T)] as the type species and Aliagarivorans taiwanensis sp. nov. [type strain is AAT1T (=BCRC 17889T=JCM 15537T)] as a second species.

Fluorination of poly(dimethylsiloxane) surfaces by low pressure CF4 plasma – physicochemical and antifouling properties

Fluorinated surface groups were introduced into poly(dimethylsiloxane) (PDMS) coatings by plasma treatment using a low pressure radio frequency discharge operated with tetrafluoromethane. Substrates were placed in a remote position downstream the discharge. Discharge power and treatment time were tuned to alter the chemical composition of the plasma treated PDMS surface. The physicochemical properties and stability of the fluorine containing PDMS were characterized by X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM) and contact angle measurements. Smooth PDMS coatings with a fluorine content up to 47% were attainable. The CF4 plasma treatment generated a harder, non-brittle layer at the top-most surface of the PDMS. No changes of surface morphology were observed upon one week incubation in aqueous media. Surprisingly, the PDMS surface was more hydrophilic after the introduction of fluorine. This may be explained by an increased exposure of oxygen containing moieties towards the surface upon re-orientation of fluorinated groups towards the bulk, and/or be a consequence of oxidation effects associated with the plasma treatment. Experiments with strains of marine bacteria with different surface energies, Cobetia marina and Marinobacter hydrocarbonoclasticus, showed a significant decrease of bacteria attachment upon fluorination of the PDMS surface. Altogether, the CF4 plasma treatments successfully introduced fluorinated groups into the PDMS, being a robust and versatile surface modification technology that may find application where a minimization of bacterial adhesion is required.

Pseudidiomarina marina sp. nov. and Pseudidiomarina tainanensis sp. nov. and reclassification of Idiomarina homiensis and Idiomarina salinarum as Pseudidiomarina homiensis comb. nov. and Pseudidiomarina salinarum comb. nov., respectively

Two Gram-negative strains of heterotrophic, aerobic, marine bacteria, designated PIM1T and PIN1T, were isolated from seawater samples collected from the shallow coastal region of An-Ping Harbour, Tainan, Taiwan. Cells grown in broth cultures were straight rods and non-motile. The two isolates required NaCl for growth and grew optimally at 30-35 degrees C and 2-5 % NaCl. They grew aerobically and were not capable of anaerobic growth by fermentation of glucose or other carbohydrates. The cellular fatty acids were predominantly iso-branched, with iso-C(15 : 0) (17.0-21.4 %), iso-C(17 : 0) (18.2-21.0 %) and iso-C(17 : 1)omega9c (15.7-16.6 %) as the most abundant components. The predominant isoprenoid quinone was Q-8 (95.2-97.1 %). Strains PIM1T and PIN1T had DNA G+C contents of 46.6 and 46.9 mol%, respectively. Phylogeny based on 16S rRNA gene sequences and DNA-DNA hybridization, together with data from physiological, morphological and chemotaxonomic characterizations, indicated that the two isolates should be classified as representatives of two novel species of the genus Pseudidiomarina of the family Idiomarinaceae, for which the names Pseudidiomarina marina sp. nov. (type strain PIM1T=BCRC 17749T=JCM 15083T) and Pseudidiomarina tainanensis sp. nov. (type strain PIN1T=BCRC 17750T=JCM 15084T) are proposed. In addition, based on the characterization data obtained in this study, it is proposed that Idiomarina homiensis and Idiomarina salinarum should be reclassified as Pseudidiomarina homiensis comb. nov. and Pseudidiomarina salinarum comb. nov., respectively.

Distributions of phospholipid and glycolipid fatty acids in two strains of different functional Erythrobacter sp. isolated from South China Sea

The comparison of the fatty acids between aerobic anoxygenic phototrophic bacteria (AAPB) and their phylogenetic relatives has been a fascinating but yet enigmatic topic, enhancing our understanding of physiological variations between these evolutionarily related microorganisms. Two strains of marine bacteria, both phylogenetically falling into Erythrobacter sp., were isolated from the South China Sea, and demonstrated, respectively, to be an aerobic anoxygenic phototrophic bacteria (AAPB) (JL475) which is capable of anoxygenic photosynthesis via BChl a, and an obligate heterotroph (JL316) with a lack of BChl a, on the basis of phylogenetic analysis and pure culture cultivation. Phospholipid fatty acids (PLFA) and glycolipid fatty acids (GLFA) of the two strains were extracted and analyzed by gas chromatographymass spectrometry. The PLFA in JL475 AAPB are characterized by C18:1 C18:2ω7,13 and C18:1, with the C18:2ω7,13 being a specific compound for AAPB and in particular for Erythrobacter longus and some of its phylogenetically closely related relatives. The JL316 strain is characterized in PLFA by the presence of C18:1, C16:1 and C16:0, and in particular C17:1. GLFA do not show any discrimination between the two strains. Four α,ω-dicarboxylic acids, including 1,8-octanedioic acid, 1,9-nonanedioic acid, 1,10-decanedioic acid and 1,11-undecanedioic acid, are present only in JL316 GLFA, presumably derived from metabolic products. C14-C16 2-hydroxy fatty acids were found in the two strains, probably assuming a similar function of their LPS in outer membranes.

Purification and characterization of antibacterial substances produced by a marine bacteriumPseudoalteromonas haloplanktisstrain

To purify and characterize compounds with antimicrobial activity from Pseudoalteromonas haloplanktis inhibition (INH) strain. The P. haloplanktis isolated from a scallop hatchery was used to analyse antibacterial activities. Crude extracts were obtained with ethyl acetate of the cultured broth, after separation of bacterial cells, and assays against six strains of marine bacteria and nine clinically important pathogenic bacteria. The active compounds were purified from ethyl acetate extracts, by a combination of SiO(2) column and thin layer chromatography. Two active fractions were isolated, and chemical structures of two products from the major one were unambiguously identified as isovaleric acid (3-methylbutanoic acid) and 2-methylbutyric acid (2-methylbutanoic acid), by comparing their mass spectra and (1)H- and (13)C-nuclear magnetic resonance spectra to those of authentic compounds. In the antibacterial activity of P. haloplanktis INH strain, extra cell compounds are involucred, mainly isovaleric and 2-methylbutyric acids. Production of antimicrobial compounds by marine micro-organisms has been widely reported; however, the efforts not always are conducted to purification and applications of these active compounds. This study is a significant contribution to the knowledge of compounds unique from marine bacteria as potential sources of new drugs in the pharmacological industry.

Isolation and Characterization of Two Groups of Novel Marine Bacteria Producing Violacein

Thirteen strains of novel marine bacteria producing a purple pigment were isolated from the Pacific coast of Japan. They were divided into two groups based on their 16S ribosomal RNA gene sequences, and both groups of bacteria belonged to the genus Pseudoalteromonas. The UV-visible spectrum of the pigment was identical to those of violacein, a pigment produced by several species of bacteria including Chromobacterium violaceum, an opportunistic pathogen. Further analysis of the chemical structure of the pigment by mass spectroscopy and nuclear magnetic resonance spectroscopy showed that the pigment was violacein. The high purity of violacein in the crude extract enabled us to employ simple and nonpolluting procedures to purify the pigment. Isolated bacteria may be useful as a C. violaceum substitute for the safe production of violacein.

Cloning of complete genes for novel hydrolytic enzymes from Antarctic sea water bacteria by use of an improved genome walking technique

The increased demand for enzymes with new properties makes indispensable the development of easy and rapid strategies to obtain complete genes of new enzymes. Here a strategy is described which includes screening by PCR of new subtilases mediated by Consensus-Degenerate Hybrid Oligonucleotide Primers (CODEHOP) and an improved genome walking method to obtain the complete sequence of the identified genes. Existing methods of genome walking have many limitations, which make them inefficient and time consuming. We have developed an improved genome walking method with novel advances to get a simple, rapid and more efficient procedure based on cassette-ligation. Improvements consist basically in the possibility of a genomic DNA digestion with any restriction enzyme, blunting and 3′ adenylation of digested DNA by Taq DNA polymerase to avoid self-circularization, followed by TA ligation of the adenine 3′ overhanging end to the same unphosphorylated oligo-cassette. The efficiency of the genome walking method was demonstrated by finding the unknown ends of all gene fragments tested, previously obtained by CODEHOP-mediated PCR, including three subtilases (P4, P6 and P7), one xylanase and one lipase, from different strains of Antarctic marine bacteria.

Iron effects on colonization behavior, motility, and enzymatic activity of marine bacteria

Iron availability in the ocean has been shown to affect the growth and production of phytoplankton and free-living bacteria. A large fraction of marine bacteria are specialized in colonizing and living on particles and aggregates, but the effects of iron limitation on these bacteria are not fully known. We conducted laboratory experiments to study the effects of iron availability on particle colonization behavior, motility, and enzymatic activities of 4 strains of marine bacteria. Iron depletion reduced the bacterial particle colonization rate by 1.7%-43.1%, which could be attributed to reduced swimming speeds in 2 of the 4 strains. Protease activity was not affected by iron availability. However, attached bacteria did show higher protease activities than their free counterparts. Our results suggest that iron limitation in the ocean could in some cases reduce bacteria-particle interactions by reducing bacterial motility and colonization rate.

Alteromonas tagae sp. nov. and Alteromonas simiduii sp. nov., mercury-resistant bacteria isolated from a Taiwanese estuary

Two mercury-resistant strains of heterotrophic, aerobic, marine bacteria, designated AT1(T) and AS1(T), were isolated from water samples collected from the Er-Jen River estuary, Tainan, Taiwan. Cells were Gram-negative rods that were motile by means of a single polar flagellum. Buds and prosthecae were produced. The two isolates required NaCl for growth and grew optimally at about 30 degrees C, 2-4 % NaCl and pH 7-8. They grew aerobically and were incapable of anaerobic growth by fermenting glucose or other carbohydrates. They grew and expressed Hg(2+)-reducing activity in liquid media containing HgCl(2). Strain AS1(T) reduced nitrate to nitrite. The predominant isoprenoid quinone was Q(8) (91.3-99.9 %). The polar lipids of strain AT1(T) consisted of phosphatidylethanolamine (46.6 %), phosphatidylglycerol (28.9 %) and sulfolipid (24.5 %), whereas those of AS1(T) comprised phosphatidylethanolamine (48.2 %) and phosphatidylglycerol (51.8 %). The two isolates contained C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH (22.4-33.7 %), C(16 : 0) (19.0-22.7 %) and C(18 : 1)omega7c (11.3-11.7 %) as the major fatty acids. Strains AT1(T) and AS1(T) had DNA G+C contents of 43.1 and 45.3 mol%, respectively. Phylogeny based on 16S rRNA gene sequences, together with data from morphological, physiological and chemotaxonomic characterization, indicated that the two isolates could be classified as representatives of two novel species in the genus Alteromonas, for which the names Alteromonas tagae sp. nov. (type strain AT1(T)=BCRC 17571(T)=JCM 13895(T)) and Alteromonas simiduii sp. nov. (type strain AS1(T)=BCRC 17572(T)=JCM 13896(T)) are proposed.

Distribution of intracellular fucoidan hydrolases among marine bacteria of the family Flavobacteriaceae

A search for fucoidan-degrading enzymes and other O-glycosylhydrolases has been performed among 51 strains of marine bacteria of the family Flavobacteriaceae isolated from red, green, and brown algae, as well as from the sea urchin Strongylocentrotus intermedius and the holothurian Apostichopus japonicus. Over 40% of the studied strains synthesized fucoidanases. The marine bacteria Mesonia algae KMM 3909(T) (an isolate from green alga Acrosiphonia sonderi), as well as Maribacter sp. KMM 6211 and Gramella sp. KMM 6054 (associants of the sea urchin S. intermedius), were the best producers of fucoidanases. Xylose effectively induced the biosynthesis of fucoidanases in these strains. None of the 15 strains of marine bacteria belonging to the genus Arenibacter produced polysaccharide hydrolases.

The study of antagonistic interactions among pelagic bacteria: a promising way to coin environmental friendly antifouling compounds

Ten strains of marine bacteria (SCH0401–SCH0410) were isolated from Ayajin, the east coast of South Korea. In spectrophotometer based chemotaxis assay the ethyl acetate extract (300 μg) of SCH0402 decreased the optical density (OD) of the motile target strains SCH0401, SCH0402, SCH0407 and SCH0408 by two to six times when compared to control. Tributyltin oxide (TBTO) decreased the OD of all target strains by only two times. The most active strain SCH0402 was identified as Shewanella oneidensis by using 16S rDNA gene sequence analysis. Similarly, the target motile strains SCH0401, SCH0402, SCH0407 and SCH0408 were identified as Alteromonas marina, Shewanella oneidensis, Roseobacter gallaeciensis and Bacillus atrophaeus, respectively. The growth inhibition zone produced by the test bacterial extracts against the target strains were three to eight times smaller when compared to that of TBTO. Even though, SCH0402 showed six times weaker antibacterial activity, the repellent activity was three times stronger than TBTO. Therefore, the higher negative chemotactic activity would be better to select eco-friendly antifouling compounds than the other antibacterial activities.