Species Of Marine Bacteria Research Articles

Synthesis and Antibacterial Activity of Erythromycin 9-Acylhydrazone Derivates.

Some species of Marine bacteria pose great risks to human and mariculture organisms. Meanwhile, Vibrio harveyi and Vibrio parahaemolyticus strains have acquired resistance to many antibiotics. A novel series of erythromycin 9-acylhydrazone derivatives were synthesized and evaluated for their in vitro antibacterial activity against marine pathogens. The site-selective N-acylation of erythromycin hydrazone was achieved using acid chloride/ triethylamine in methanol as the reaction system. All the synthesized target compounds were evaluated for their antibacterial activity by determination of minimum inhibitory concentrations (MICs) using the broth microdilution method. All the tested acylhydrazone compounds showed moderate to high activity with MIC value 0.125-1 μg/mL against Vibrio parahaemolyticus and Vibrio harveyi. The introduction of the acylhydrazone moiety at the C-9 position of erythromycin improved its activity against the above-mentioned marine bacteria strains.

Optimization of Fermentation Conditions for Carrageenase Production by Cellulophaga Species: A Comparative Study.

Simple SummaryCellulophaga species are rarely studied marine bacteria with the potential for carrageenase production. We examined the carrageenase secretion ability of six bacterial species from the Cellulophaga genus. Among them, C. algicola produced the maximum amount of ι-carrageenase. Most of the bacteria produced their highest quantity of enzymes at 25 °C after 48 h of incubation time. The maximum enzyme production was achieved with the fermentation medium composition of 30 g/L sea salt, 1.4 g/L furcellaran and 3 g/L yeast extract. In addition, the properties of the ultrafiltered ι-carrageenase extracted from C. algicola were studied.Carrageenases appear in various species of marine bacteria and are widely used for the degradation of carrageenans, the commercially significant sulphated polysaccharides. The carrageenase production ability of six different Cellulophaga species was identified, with ι-carrageenase being the most abundant carrageenolytic enzyme. C. algicola was the most potent strain, followed by C. fucicola and C. geojensis, whereas C. pacifica was the least effective carrageenase producer among the studied strains. The enzyme production was maximized using the one-factor-at-a-time optimization method. The optimal incubation temperature was identified as 25 °C and the incubation time was set as 48 h for all tested species. The optimal medium composition for Cellulophaga strains was determined as 30 g/L sea salt, 1.4 g/L furcellaran, and 3 g/L yeast extract. An ultrafiltered enzyme extracted from C. algicola had the highest activity at around 40 °C. The optimal pH for enzymatic degradation was determined as 7.8, and the enzyme was fairly stable at temperatures up to 40 °C.

Ecological Fitness of Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus in a Small-Scale Population Dynamics Study

The potential spread of infectious diseases in response to climate change and rising sea surface temperatures in temperate regions has been a growing concern for the past several decades. Extreme heat waves in the North Atlantic and North Sea regions have been correlated with an increase in human Vibrio infections; of particular concern to human health are Vibrio cholerae, Vibrio parahaemolyticus, and Vibrio vulnificus. While these species are well-known to cause disease in humans, most environmental strains are not pathogenic. Studying not only the behavior of the pathogenic strains, but that of non-pathogenic environmental isolates, may better elucidate their ecological relationship in their native microbiome and the dispersal of these species in coastal regions. Using red fluorescent protein-tagged and gentamycin-resistant V. cholerae, V. parahaemolyticus, and V. vulnificus strains, we investigated whether increasing temperatures confer greater competitive fitness to these species when incubated within a natural North Sea water sample still containing its microbiome in a small-scale niche investigation. Increased incubation temperatures alone did not confer a competitive advantage to V. cholerae, V. parahaemolyticus, and V. vulnificus. The microbial community could limit Vibrio growth at all temperatures. To the best of our knowledge, we also demonstrate the first (albeit unintentional) genetic modification of multiple species of marine bacteria through the introduction of a genetically modified V. vulnificus strain into a natural water sample in a contained system.

NaCl Concentration-Dependent Aminoglycoside Resistance of Halomonas socia CKY01 and Identification of Related Genes.

Among various species of marine bacteria, those belonging to the genus Halomonas have several promising applications and have been studied well. However, not much information has been available on their antibiotic resistance. In our efforts to learn about the antibiotic resistance of strain Halomonas socia CKY01, which showed production of various hydrolases and growth promotion by osmolytes in previous study, we found that it exhibited resistance to multiple antibiotics including kanamycin, ampicillin, oxacillin, carbenicillin, gentamicin, apramycin, tetracycline, and spectinomycin. However, the H. socia CKY01 resistance pattern to kanamycin, gentamicin, apramycin, tetracycline, and spectinomycin differed in the presence of 10% NaCl and 1% NaCl in the culture medium. To determine the mechanism underlying this NaCl concentration-dependent antibiotic resistance, we compared four aminoglycoside resistance genes under different salt conditions while also performing time-dependent reverse transcription PCR. We found that the aph2 gene encoding aminoglycoside phosphotransferase showed increased expression under the 10% rather than 1% NaCl conditions. When these genes were overexpressed in an Escherichia coli strain, pETDuet-1::aph2 showed a smaller inhibition zone in the presence of kanamycin, gentamicin, and apramycin than the respective control, suggesting aph2 was involved in aminoglycoside resistance. Our results demonstrated a more direct link between NaCl and aminoglycoside resistance exhibited by the H. socia CKY01 strain.

Reviews and syntheses: Bacterial bioluminescence – ecology and impact in the biological carbon pump

Abstract. Around 30 species of marine bacteria can emit light, a critical characteristic in the oceanic environment is mostly deprived of sunlight. In this article, we first review current knowledge on bioluminescent bacteria symbiosis in light organs. Then, focusing on gut-associated bacteria, we highlight that recent works, based on omics methods, confirm previous claims about the prominence of bioluminescent bacterial species in fish guts. Such host–symbiont relationships are relatively well-established and represent important knowledge in the bioluminescence field. However, the consequences of bioluminescent bacteria continuously released from light organs and through the digestive tracts to the seawater have been barely taken into account at the ecological and biogeochemical level. For too long neglected, we propose considering the role of bioluminescent bacteria and reconsidering the biological carbon pump, taking into account the bioluminescence effect (“bioluminescence shunt hypothesis”). Indeed, it has been shown that marine snow and fecal pellets are often luminous due to microbial colonization, which makes them a visual target. These luminous particles seem preferentially consumed by organisms of higher trophic levels in comparison to nonluminous ones. As a consequence, the sinking rate of consumed particles could be either increased (due to repackaging) or reduced (due to sloppy feeding or coprophagy/coprorhexy), which can imply a major impact on global biological carbon fluxes. Finally, we propose a strategy, at a worldwide scale, relying on recently developed instrumentation and methodological tools to quantify the impact of bioluminescent bacteria in the biological carbon pump.

Hydrolytic Enzymes from Marine Organisms as Inhibitors of Biofilm Formation

The effects of some hydrolytic enzymes from marine organisms on the formation and destruction of bacterial biofilms have been studied. As the results show, the presence of α-D-galactosidase from the marine bacterium Pseudoalteromonas sp. KMM 701 stimulates the growth of biofilms formed by various species of marine bacteria, whereas the formation of biofilms by Bacillus subtilis and Yersinia pseudotuberculosis is inhibited by this enzyme. Treatment with α-galactosidase causes destruction of 5 to 35% of a mature biofilm of various bacterial species. Phosphodiesterase and alkaline phosphatase from the marine bacterium Cobetia amphilecti KMM 296 have an inhibitory effect on the biofilm formation by marine strains of Bacillus licheniformis, B. aegricola, and B. berkelogi, and also degrade already formed biofilms of these bacilli and Yersinia. The crab hepatopancreas DNase inhibits the biofilm formation by Y. pseudotuberculosis and B. subtilis by partially degrading a mature biofilm.

Polyhydroxyalkanoate Production from Two Species of Marine Bacteria: A Comparative Study

There are few reports of polyhydroxyalkanoates production from marine microorganisms. This work aimed to explore the marine bacteria Cobetia sp. INV PRT122 and Bacillus sp. INV FIR18 isolated from the Colombian Caribbean Sea as polyhydroxyalkanoates producers. The polymers were extracted, and structural analyses were completed to confirm their nature. Growth, accumulation, and sugar consumption kinetic studies were then conducted using glucose as a carbon source at 2%, 4%, 8%, 12% (w/v). A high degree of purity could be seen in the spectroscopy analysis through its signals, and the results indicated that the isolated polysaccharides had the same chemical structure as that of polyhydroxybutyrate. The results of the growth of the microorganisms and production of polyhydroxyalkanoates confirm that an excess of carbon affects the polymer production. The highest production was obtained from Bacillus sp. INV FIR18 using glucose at 2%, 30 °C, 140 rpm, and 144 h.

Alkaline guts contribute to immunity during exposure to acidified seawater in the sea urchin larva.

Larval stages of members of the Abulacraria superphylum including echinoderms and hemichordates have highly alkaline midguts. To date, the reason for the evolution of such extreme pH conditions in the gut of these organisms remains unknown. Here, we test the hypothesis that, analogous to the acidic stomachs of vertebrates, these alkaline conditions may represent a first defensive barrier to protect from environmental pathogens. pH-optimum curves for five different species of marine bacteria demonstrated a rapid decrease in proliferation rates by 50-60% between pH8.5 and 9.5. Using the marine bacterium Vibrio diazotrophicus, which elicits a coordinated immune response in the larvae of the sea urchin Strongylocentrotus purpuratus, we studied the physiological responses of the midgut pH regulatory machinery to this pathogen. Gastroscopic microelectrode measurements demonstrate a stimulation of midgut alkalization upon infection with V. diazotrophicus accompanied by an upregulation of acid-base transporter transcripts of the midgut. Pharmacological inhibition of midgut alkalization resulted in an increased mortality rate of larvae during Vibrio infection. Reductions in seawater pH resembling ocean acidification conditions lead to moderate reductions in midgut alkalization. However, these reductions in midgut pH do not affect the immune response or resilience of sea urchin larvae to a Vibrio infection under ocean acidification conditions. Our study addressed the evolutionary benefits of the alkaline midgut of Ambulacraria larval stages. The data indicate that alkaline conditions in the gut may serve as a first defensive barrier against environmental pathogens and that this mechanism can compensate for changes in seawater pH.

Artificial covalent linkage of bacterial acyl carrier proteins for fatty acid production

Acyl carrier proteins (ACPs) are essential to the production of fatty acids. In some species of marine bacteria, ACPs are arranged into tandem repeats joined by peptide linkers, an arrangement that results in high fatty acid yields. By contrast, Escherichia coli, a relatively low producer of fatty acids, uses a single-domain ACP. In this work, we have engineered the native E. coli ACP into tandem di- and tri-domain constructs joined by a naturally occurring peptide linker from the PUFA synthase of Photobacterium profundum. The size of these tandem fused ACPs was determined by size exclusion chromatography to be higher (21 kDa, 36 kDa and 141 kDa) than expected based on the amino acid sequence (12 kDa, 24 kDa and 37 kDa, respectively) suggesting the formation of a flexible extended conformation. Structural studies using small-angle X-ray scattering (SAXS), confirmed this conformational flexibility. The thermal stability for the di- and tri-domain constructs was similar to that of the unfused ACP, indicating a lack of interaction between domains. Lastly, E. coli cultures harboring tandem ACPs produced up to 1.6 times more fatty acids than wild-type ACP, demonstrating the viability of ACP fusion as a method to enhance fatty acid yield in bacteria.

Characterization of Marine Bioflocculant-producing Bacteria Isolated From Biofloc of Pacific Whiteleg Shrimp, Litopenaeus vannamei Culture Ponds

Characterization of marine bioflocculant-producing bacteria isolated from bioflocs of Pacific whiteleg shrimp, Litopenaeus vannamei culture ponds was prompted to explore the bacteria that enhanced bioflocculation process in aquaculture wastewater treatment. Certain marine bacteria were potentially secreted extracellular polymeric substances (EPS) which response to the physiological stress encountered in the natural environment that can act as bioflocculants. This study aimed to identify marine bioflocculant-producing bacteria isolated from biofloc; to evaluate their flocculating activities; and to characterize their protein in EPS. Phenotypic and genotypic identification of the bacteria including morphological and molecular approaches were employed, while their flocculating activities were examined via Kaolin clay suspension method and statistically analyzed. The EPS that acted as bioflocculants were extracted using cold ethanol precipitation method. Protein concentration was determined by Bradford assay and protein profiling was finally completed with Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis (SDS-PAGE) method. Six species of marine bacteria known as Halomonas venusta, Bacillus cereus, Bacillus subtilis, Bacillus pumilus, Nitratireductor aquimarinus and Pseudoalteromonas sp. were successfully identified as bioflocculant-producing bacteria. The highest flocculating activity was exhibited by Bacillus cereus at 93%, while Halomonas venusta showed the lowest record at 59%. All bioflocculant -producing bacteria species showed different protein concentration that ranged between 1.377 μg/mL to 1.455 μg/mL. Several protein bands with different molecular weight that ranged between 16 kDa to 100 kDa were observed. This study revealed that all the identified bacteria species have high potential characteristics to initiate aquaculture wastewater treatment and may play important roles in bioflocculation process.

Mechanisms and Origin of Bacterial Biolumenescence

The origin of bioluminescence in living organisms was first mentioned by Charles Darwin (1859) and remains obscure despite significant success achieved over the past decades. Here we discuss the mechanisms of bacterial bioluminescence. We have the main results from structural and functional analysis of the genes of lux operons, enzymes (luciferase), and mechanisms of bioluminescence in several species of marine bacteria, which belong to three genera, Vibrio, Aliivibrio, and Photobacterium (A. fischeri, V. harveyi, P. leiognathi, and P. phosphoreum), and in terrestrial bacteria of the genus Photorhabdus (Ph. luminescens). The structure and mechanisms for the regulation of the expression of the lux operons are discussed. The fundamental characteristics of luciferase and luciferase-catalyzed reactions (stages of FMNH2 and tetradecanal oxidation, dimensional structure, as well as folding and refolding of the macromolecule) are described. We also discuss the main concepts of the origin of bacterial bioluminescence and its role in the ecology of modern marine fauna, including its involvement in the processes of detoxification of the reactive oxygen species and DNA repair, as well as the bait hypothesis.

Potential Threats Posed by Tetrodotoxins in UK Waters: Examination of Detection Methodology Used in Their Control.

Tetrodotoxin is a neurotoxin responsible for many human fatalities, most commonly following the consumption of pufferfish. Whilst the source of the toxin has not been conclusively proven, it is thought to be associated with various species of marine bacteria. Whilst the toxins are well studied in fish and gastropods, in recent years, there have been a number of reports of tetrodotoxin occurring in bivalve shellfish, including those harvested from the UK and other parts of Europe. This paper reviews evidence concerning the prevalence of tetrodotoxins in the UK together with methodologies currently available for testing. Biological, biomolecular and chemical methods are reviewed, including recommendations for further work. With the recent development of quantitative chromatographic methods for these and other hydrophilic toxins, as well as the commercial availability of rapid testing kits, there are a number of options available to ensure consumers are protected against this threat.

Competitive strategies differentiate closely related species of marine actinobacteria.

Although competition, niche partitioning, and spatial isolation have been used to describe the ecology and evolution of macro-organisms, it is less clear to what extent these principles account for the extraordinary levels of bacterial diversity observed in nature. Ecological interactions among bacteria are particularly challenging to address due to methodological limitations and uncertainties over how to recognize fundamental units of diversity and link them to the functional traits and evolutionary processes that led to their divergence. Here we show that two closely related marine actinomycete species can be differentiated based on competitive strategies. Using a direct challenge assay to investigate inhibitory interactions with members of the bacterial community, we observed a temporal difference in the onset of inhibition. The majority of inhibitory activity exhibited by Salinispora arenicola occurred early in its growth cycle and was linked to antibiotic production. In contrast, most inhibition by Salinispora tropica occurred later in the growth cycle and was more commonly linked to nutrient depletion or other sources. Comparative genomics support these differences, with S. arenicola containing nearly twice the number of secondary metabolite biosynthetic gene clusters as S. tropica, indicating a greater potential for secondary metabolite production. In contrast, S. tropica is enriched in gene clusters associated with the acquisition of growth-limiting nutrients such as iron. Coupled with differences in growth rates, the results reveal that S. arenicola uses interference competition at the expense of growth, whereas S. tropica preferentially employs a strategy of exploitation competition. The results support the ecological divergence of two co-occurring and closely related species of marine bacteria by providing evidence they have evolved fundamentally different strategies to compete in marine sediments.

Vitroprocines, new antibiotics against Acinetobacter baumannii, discovered from marine Vibrio sp. QWI-06 using mass-spectrometry-based metabolomics approach.

A robust and convenient research strategy integrating state-of-the-art analytical techniques is needed to efficiently discover novel compounds from marine microbial resources. In this study, we identified a series of amino-polyketide derivatives, vitroprocines A-J, from the marine bacterium Vibrio sp. QWI-06 by an integrated approach using imaging mass spectroscopy and molecular networking, as well as conventional bioactivity-guided fractionation and isolation. The structure-activity relationship of vitroprocines against Acinetobacter baumannii is proposed. In addition, feeding experiments with 13C-labeled precursors indicated that a pyridoxal 5′-phosphate-dependent mechanism is involved in the biosynthesis of vitroprocines. Elucidation of amino-polyketide derivatives from a species of marine bacteria for the first time demonstrates the potential of this integrated metabolomics approach to uncover marine bacterial biodiversity.

Compositional similarities and differences between transparent exopolymer particles (TEPs) from two marine bacteria and two marine algae: Significance to surface biofouling

Transparent-exopolymer-particles (TEPs) have been recently identified as a significant contributor to surface biofouling, such as on reverse osmosis (RO) membranes. TEP research has mainly focused on algal TEP/TEP precursors while limited investigations have been conducted on those released by bacteria. In this study, TEP/TEP precursors derived from both algae and bacteria were isolated and then characterized to investigate their similarities and/or differences using various advanced analytical techniques, thus providing a better understanding of their potential effect on biofouling. Bacterial TEP/TEP precursors were isolated from two species of marine bacteria (Pseudidiomarina homiensis and Pseudoalteromonas atlantica) while algal TEP/TEP precursors were isolated from two marine algae species (Alexandrium tamarense and Chaetoceros affinis).Results indicated that both isolated bacterial and algal TEP/TEP precursors were associated with protein-like materials, and most TEP precursors were high-molecular-weight biopolymers. Furthermore all investigated algal and bacterial TEP/TEP precursors showed a lectin-like property, which can enable them to act as a chemical conditioning layer and to agglutinate bacteria. This property may enhance surface biofouling. However, both proton nuclear magnetic resonance (NMR) spectra and the nitrogen/carbon (N/C) ratios suggested that the algal TEP/TEP precursors contained much less protein content than the bacterial TEP/TEP precursors. This difference may influence their initial deposition and further development of surface biofouling.

Improving UV seawater disinfection with immobilized TiO2: Study of the viability of photocatalysis (UV254/TiO2) as seawater disinfection technology

Abstract Industries located in coastal areas and maritime transport are economic activities that use large amounts of seawater. In most cases, this water requires disinfection treatment to avoid fouling problems in industrial facilities or to prevent environmental impacts after used seawater is released. This study proposes the photocatalysis with immobilized TiO 2 as a disinfection treatment for seawater and evaluate its efficacy by comparing with UV 254 radiation treatment. The experiments were carried out employing artificial seawater and using an annular UV reactor in the laboratory scale tests. Two species of marine bacteria were used as microbial indicators of the treatment efficacy: Alteromonas sp and Corynebacterium stationis . The photocatalytic treatment had faster disinfection kinetics than that using UV 254 light for both bacteria species, being necessary between 30 and 33% less UV dose to achieve the same level of disinfection. The catalyst used for photocatalytic treatment showed a progressive decay of activity until its complete inactivation after 215 h of treatment, due to factors such as fouling or catalyst loss.

Marine compounds with therapeutic potential in gram-negative sepsis.

This paper concerns the potential use of compounds, including lipid A, chitosan, and carrageenan, from marine sources as agents for treating endotoxemic complications from Gram-negative infections, such as sepsis and endotoxic shock. Lipid A, which can be isolated from various species of marine bacteria, is a potential antagonist of bacterial endotoxins (lipopolysaccharide (LPSs)). Chitosan is a widespread marine polysaccharide that is derived from chitin, the major component of crustacean shells. The potential of chitosan as an LPS-binding and endotoxin-neutralizing agent is also examined in this paper, including a discussion on the generation of hydrophobic chitosan derivatives to increase the binding affinity of chitosan to LPS. In addition, the ability of carrageenan, which is the polysaccharide of red alga, to decrease the toxicity of LPS is discussed. We also review data obtained using animal models that demonstrate the potency of carrageenan and chitosan as antiendotoxin agents.

Integrating conjugative elements of the SXT/R391 family from fish-isolatedVibriosencode restriction-modification systems that confer resistance to bacteriophages

Integrating conjugative elements (ICEs) of the SXT/R391 family have been described in Vibrios, mainly Vibrio cholerae, and other bacteria as carriers of variable gene content conferring adaptive advantages upon their hosts, including antimicrobial resistance and motility regulation. However, our knowledge on their host range and ecological significance is still limited. Here, we report the identification and characterization of ICEVspPor3 and ICEValSpa1, two novel ICEs of the SXT/R391 family from fish-isolated Vibrio splendidus and Vibrio alginolyticus, respectively. We found that ICEVspPor3 carries tetracycline and HgCl(2) resistance determinants and can be transferred by conjugation to Escherichia coli and to several species of marine bacteria including some of the major bacterial fish pathogens in marine aquaculture, whereas ICEValSpa1 lacks resistance genes. Interestingly, both ICEs harbor genes encoding distinct restriction-modification (RM) systems. We demonstrate here that these RM systems, when expressed in E.coli, confer protection to infection by T1 bacteriophage and by environmental water bacteriophages. Our results provide evidences that the variable gene content of ICEs of the SXT/R391 family encodes fitness functions beyond those related to antimicrobial resistance and motility regulation and suggest that the host range of these elements in the marine environment might be broader than expected.

Pseudoalteromonas strains are potent immunomodulators owing to low-stimulatory LPS

Many species of marine bacteria elicit a weak immune response. In this study, the aim was to assess the immunomodulatory properties of Gram-negative Pseudoalteromonas strains compared with other marine Gram-negative bacteria and to identify the molecular cause of the immunomodulation. Using murine bone-marrow derived dendritic cells (DCs), it was found that Pseudoalteromonas strains induced low cytokine production and modest up-regulation of surface markers CD40 and CD86 compared with other marine bacteria and Escherichia coli LPS. Two strains, Ps. luteoviolacea and Ps. ruthenica, were further investigated with respect to their immunomodulatory properties in DCs. Both inhibited IL-12 and increased IL-10 production induced by E. coli LPS. LPS isolated from the two Pseudoalteromonas strains had characteristic lipid A bands in SDS-PAGE. Stimulation of HEK293 TLR4/MD2 cells with the isolated LPS confirmed the involvement of LPS and TLR4 and established Pseudoalteromonas LPS as TLR4 antagonists. The isolated LPS was active in the endotoxin limulus amoebocyte lysate assay and capable of inducing increased endocytosis in DCs. This study highlights that antagonistic LPS from Pseudoalteromonas strains has potential as a new candidate of therapeutic agent capable of modulating immune responses.

광양만 해역에서의 고효율 질소-인 제거 해양박테리아 탐색 및 분리

371 균주의 해양박테리아를 광양만에서 분리하였다. 우점종은 Pseudomonas aeruginosa, Aeromonas hydrophila, P. fluorescens, P. paucimobilis, Chryseomonas luteola, P. vescularis 등이었다. 영양염과 유기물을 제거할 수 있는 해양박테리아를 탐색하기 위하여 암모니아성 질소(100 mg/L), 질산성 질소(100 mg/L) 및 인(10 mg/L)이 각각 포함된 10 mL의 marine broth 2216 (DIFCO)에 해양박테리아를 접종(1.0%, v/v)하고 12시간 배양하였다. 스크리닝 테스트 결과 25% 이상 $COD_{Cr}$ 을 제거하는 해양박테리아는 16종, 15% 이상의 암모니아 질소를 제거하는 해양박테리아는 9종, 60% 이상의 질산 질소를 제거하는 해양박테리아는 11종 그리고 90% 이상의 인을 제거하는 해양박테리아는 13종이 분리되었다. Aeromonas hydrophila, Chryseomonas indologenes, Pseudomonas diminuta, Vibrio parahaemolyticus 균주가 유기물 및 영양염류 제거실험을 위해 선정되었다. 회분식 시험을 위해 4종의 해양박테리아를 $COD_{Cr}$ 250 mg/L, $NH_3-N$ 40 mg/L, ${NO_3}^{-}-N$ 40 mg/L, ${PO_4}^{3-}-P$ 10 mg/L이 각각 첨가되어 있는 변형 marine broth에 접종하고, 10시간 배양하면서 제거효율을 측정하였다. 【371 strains of marine bacteria were isolated from Gwangyang bay in Korea. The dominant species were identified as Pseudomonas aeruginosa, Aeromonas hydrophila, P. fluorescens, P. paucimobilis, Chryseomonas luteola and P. vescularis. To screen marine bacteria capable of removing nutrients and organics, marine bacteria was inoculated in 10 mL of marine broth 2216 (DIFCO) with $NH_3-N$ (100 mg/L), ${NO_3}^{-}-N$ (100 mg/L), and ${PO_4}^{-3}-P$ (10 mg/L) with 1.0% (v/v), and incubated for 12 h. Results from the screening test, showed that the removal efficiencies for $COD_{Cr}$ , ammonia niterogen, nitrate nitrogen, and phosphate were over 25% for 16 strains, 15% for 9 strains, 50% for 63 strains, and 15% for 80 strains, respectively. Aeromonas hydrophila, Chryseomonas indologenes, Pseudomonas diminuta, Vibrio parahaemolyticus were selected for nutrients removal experiments. For the batch test, 4 species of marine bacteria were inoculated in modified marine broth containing with nutrients( $COD_{Cr}$ 250 mg/L, $NH_3-N$ 40 mg/L, ${NO_3}^{-}-N$ 40 mg/L, ${PO_4}^{3-}-P$ 10 mg/L, respectively), incubated for 10 hr and the removal efficiencies were measured.】