Complete genome sequence of the novel Antarctic Oceanisphaera sp. IT1-181 that carried five plasmids.

Bacteria of the genus Oceanisphaera in the class Gammaproteobacteria are widely distributed in marine environments. Oceanisphaera sp. IT1-181 was isolated from intertidal sediment in the coastal region of the Chinese Great Wall Station on the Fildes Peninsula, King George Island, Antarctica. Here, we sequenced the complete genome of strain IT1-181, which contained a single chromosome of 3,572,184 bp (G + C content of 49.89 mol%) with five plasmids. A total of 3229 protein-coding genes, 88 tRNA genes, and 25 rRNA genes were obtained. Genome sequence analysis revealed that strain IT1-181 was not only a potentially novel species of the genus Oceanisphaera, but also harbored genes involved in biosynthesizing ectoine as well as poly-ß-hydroxybutyric acid (PHB). In addition, genes of a complete type I-E CRISPR-Cas system were found in the bacterium. The results indicate the potential of strain Oceanisphaera sp. IT1-181 in biotechnology and are helpful for us understanding its ecological roles in the changing Antarctic intertidal zone environment.

Zobellella iuensis sp. nov., an aerobic denitrifying bacterium isolated from activated sludge.

An aerobic denitrifying bacterium, designated as strain CPY4T, was isolated from activated sludge treating urban sewage under alternating aerobic/anaerobic conditions by an enrichment culture technique. Cells of strain CPY4T were Gram-stain-negative, aerobic, long rod-shaped, motile by means of single polar flagellum and capable of aerobic denitrification with citrate as the carbon source. Growth of strain CPY4T was observed at 10-45 °C (optimum, 30-35 °C), at pH 6.0-10.5 (optimum, pH 8.0-8.5) and in 0-5 % NaCl (optimum, 0-3 %; w/v). The 16S rRNA gene sequence of strain CPY4T showed the highest similarity to Zobellella denitrificans ZD1T (97.9 %), followed by Zobellella endophytica 59N8T (97.6 %), Zobellella aerophila JC2671T (97.2 %), Zobellella taiwanensis ZT1T (97.1 %) and Zobellella maritima 102-Py4T (96.3 %). Genome comparisons between CPY4T and other Zobellella species showed highest digital DNA-DNA hybridization with Z. denitrificans ZD1T (43.8 %) and highest average nucleotide identity (ANIb and ANIm) of genome nucleotide sequences with Z. denitrificans ZD1T(90.7 and 92 %, respectively). Phylogenetic analysis revealed that strain CPY4T fell within the clade comprising the type strains of Zobellella species and formed a phyletic line with them, which was distinct from other members of the family Aeromonadaceae. The sole respiratory ubiquinone was quinone 8. The predominant fatty acids (>10 % of the total fatty acids) of strain CPY4T were summed feature 8 (C18 : 1 ω6c and/or C18 : 1 ω7c), summed feature 3 (C16 : 1 ω6c and/or C16 : 1 ω7c) and C16 : 0. The genomic DNA G+C content was 62.7 mol %. In the polar lipid profile, diphosphatidylglycerol, phosphatidylglycerol, phosphatidyl ethanolamine, phospholipids and aminolipids were the major compounds. Based on the genotypic and phenotypic data, strain CPY4T represents a novel species of the genus Zobellella, for which the name Zobellella iuensis sp. nov. is proposed. The type strain is CPY4T (=JCM 34456T=CGMCC 1.18722T).

Molecular basis of transcriptional repression of anti-CRISPR by anti-CRISPR-associated 2.

CRISPR-Cas systems are well known host defense mechanisms that are conserved in bacteria and archaea. To counteract CRISPR-Cas systems, phages and viruses have evolved to possess multiple anti-CRISPR (Acr) proteins that can inhibit the host CRISPR-Cas system via different strategies. The expression of acr genes is controlled by anti-CRISPR-associated (Aca) proteins that bind to an upstream promoter and regulate the expression of acr genes during transcription. Although the role of Aca as a transcriptional repressor has been demonstrated, the mechanism of action of Aca has not been determined. Here, the molecular mechanism underlying the Aca2-mediated transcriptional control of acr genes was elucidated by determining the crystal structure of Aca2 from Oceanimonas smirnovii at a high resolution of 1.92 Å. Aca2 forms a dimer in solution, and dimerization of Aca2 is critical for specific promoter binding. The promoter-binding strategy of dimeric Aca2 was also revealed by performing mutagenesis studies. The atomic structure of the Aca family shown in this study provides insights into the fine regulation of host defense and immune-escape mechanisms and also demonstrates the conserved working mechanism of the Aca family.

Production of extracellular lipase from psychrotrophic bacterium Oceanisphaera sp. RSAP17 isolated from arctic soil.

Cold-active extracellular lipases produced by different psychrotrophs are important for various industrial applications. We have isolated a Gram-negative, rod-shaped, aerobe, non-pigment producing psychrotrophic bacterial strain RSAP17 (MTCC 12991, MCC 4275) from the unexplored Arctic soil sample of NyAlesund, Svalbard, Norway (78° 55″ N, 11° 54″ E). The detailed morphological, biochemical, and molecular characteristics were investigated to characterize the isolate RSAP17. Analyses of the 16S rDNA sequence of strain RSAP17 (Accession no. MK391379) shows the closest match with Oceanisphaera marina YM319T (99.45%) and Oceanisphaera sediminis TW92 JCM 17329T (97.40%). The isolate is capable of producing extracellular lipase but not amylase, cellulase or urease. The optimal parameters for lipase production have been found in tributyrin based (10 mL/L) agar media supplemented with 3% (w/v) NaCl after 2-3 days of incubation at 20-22 °C temperature and pH 9 at shaking condition. We have purified the extracellular lipase from the RSAP17 grown culture supernatant through 75% ammonium sulfate precipitation followed by dialysis and DEAE cellulose column chromatography. The invitro lipolytic activity of the purified lipase enzymes has been done through zymogram analysis. The molecular weight found for the lipase is 103.8 kD. The optimal activity of the purified lipase has been found at 25 °C and pH 9. MALDI-TOF-MS study of the purified lipase showed the highest match with the sequence of prolipoprotein diacylglyceryl transferase with 44% sequence coverage. Further study on large-scale production, substrate utilization and enzymatic kinetics of this lipase could unravel its possibility in future biotechnological applications.

High Water Density at Non-Ice-Binding Surfaces Contributes to the Hyperactivity of Antifreeze Proteins.

Antifreeze proteins (AFPs) can bind to ice nuclei thereby inhibiting their growth and their hydration shell is believed to play a fundamental role. Here, we use molecular dynamics simulations to characterize the hydration shell of four moderately-active and four hyperactive AFPs. The local water density around the ice-binding-surface (IBS) is found to be lower than that around the non-ice-binding surface (NIBS) and this difference correlates with the higher hydrophobicity of the former. While the water-density increase (with respect to bulk) around the IBS is similar between moderately-active and hyperactive AFPs, it differs around the NIBS, being higher for the hyperactive AFPs. We hypothesize that while the lower water density at the IBS can pave the way to protein binding to ice nuclei, irrespective of the antifreeze activity, the higher density at the NIBS of the hyperactive AFPs contribute to their enhanced ability in inhibiting ice growth around the bound AFPs.

Expression and characterization of catechol 1,2-dioxygenase from Oceanimonas marisflavi 102-Na3.

The gene of catechol 1, 2-dioxygenase was identified and cloned from the genome of Oceanimonas marisflavi 102-Na3. The protein was expressed in Escherichia coli BL21 (DE3) and purified to homogeneity of a dimer with molecular mass of 69.2 kDa. The enzyme was highly stable in pH 6.0-9.5 and below 45 °C and exhibited the maximum activity at pH 8.0 and 30 °C. Being the first characterized intradiol dioxygenase from marine bacteria Oceanimonas sp., the enzyme showed catalytic activity for catechol, 3-methylcatechol, 4-methylcatechol, 3-chlorocatechol, 4-chlorocatechol and pyrogallol. For catechol, Km and Vmax were 11.2 µM and 13.4 U/mg of protein, respectively. The enzyme also showed resistance to most of the metal ions, surfactants and organic solvents, being a promising biocatalyst for biodegradation of aromatic compounds in complex environments.

Discovery of α-Glucosidase Inhibitors from Marine Microorganisms: Optimization of Culture Conditions and Medium Composition.

Various studies showed that the suppression of α-glucosidase activity can impede the glucose absorption in our body, and therefore, it can be used to treat type 2 diabetes. Hence, the compounds with anti-α-glucosidase have gained considerable attention because of their potential application in diabetes treatment. In previous literature studies, these anti-α-glucosidase compounds were extracted from plants and fungus. Less studies are being conducted to identify the anti-α-glucosidase compounds in the microbial community. In this study, 23 marine bacterial strains were screened for their potential to suppress the α-glucosidase activity. The highest inhibitory activity was exhibited by isolated L06 which was identified as Oceanimonas smirnovii EBL6. The cultivation conditions, such as temperature and pH, were optimized to increase the production of α-glucosidase inhibitors by Oceanimonas smirnovii EBL6 strain. The result findings showed that the highest yield of α-glucosidase inhibitors can be obtained at the culture time of 120 h, fermentation temperature of 30 °C, and pH 4.6. Under these conditions, the inhibitory activity of α-glucosidase can reach 81%. The IC50 of n-butanol extract was 13.89 µg/ml, while standard acarbose was 31.16 µg/ml. Overall, these findings suggest that Oceanimonas smirnovii produces α-glucosidase inhibitors and could been applied in the biochemical and medicinal fields in the future.

Lignin induced iron reduction by novel sp., Tolumonas lignolytic BRL6-1.

Lignin is the second most abundant carbon polymer on earth and despite having more fuel value than cellulose, it currently is considered a waste byproduct in many industrial lignocellulose applications. Valorization of lignin relies on effective and green methods of de-lignification, with a growing interest in the use of microbes. Here we investigate the physiology and molecular response of the novel facultative anaerobic bacterium, Tolumonas lignolytica BRL6-1, to lignin under anoxic conditions. Physiological and biochemical changes were compared between cells grown anaerobically in either lignin-amended or unamended conditions. In the presence of lignin, BRL6-1 accumulates higher biomass and has a shorter lag phase compared to unamended conditions, and 14% of the proteins determined to be significantly higher in abundance by log2 fold-change of 2 or greater were related to Fe(II) transport in late logarithmic phase. Ferrozine assays of the supernatant confirmed that Fe(III) was bound to lignin and reduced to Fe(II) only in the presence of BRL6-1, suggesting redox activity by the cells. LC-MS/MS analysis of the secretome showed an extra band at 20 kDa in lignin-amended conditions. Protein sequencing of this band identified a protein of unknown function with homology to enzymes in the radical SAM superfamily. Expression of this protein in lignin-amended conditions suggests its role in radical formation. From our findings, we suggest that BRL6-1 is using a protein in the radical SAM superfamily to interact with the Fe(III) bound to lignin and reducing it to Fe(II) for cellular use, increasing BRL6-1 yield under lignin-amended conditions. This interaction potentially generates organic free radicals and causes a radical cascade which could modify and depolymerize lignin. Further research should clarify the extent to which this mechanism is similar to previously described aerobic chelator-mediated Fenton chemistry or radical producing lignolytic enzymes, such as lignin peroxidases, but under anoxic conditions.

Melatonin attenuates microbiota dysbiosis of jejunum in short-term sleep deprived mice.

Our study demonstrated that sleep deprivation resulted in homeostasis disorder of colon. Our study goes deeper into the positive effects of melatonin on small intestinal microbiota disorder caused by sleep deprivation. We successfully established a multiplatform 72 h sleep deprivation mouse model with or without melatonin supplementation, and analyzed the change of small intestinal microbiota using high-throughput sequencing of the 16S rRNA. We found melatonin supplementation suppressed the decrease of plasma melatonin level in sleep deprivation mice. Meanwhile, melatonin supplementation improved significantly the reduction in OTU numbers and the diversity and richness of jejunal microbiota and the abundance of Bacteroidaeae and Prevotellaceae, as well as an increase in the Firmicutes-to-Bacteroidetes ratio and the content of Moraxellaceae and Aeromonadaceae in the jejunum of sleep deprived-mice. Moreover, melatonin supplementation reversed the change of metabolic pathway in sleep deprived-mice, including metabolism, signal transduction mechanisms and transcription etc, which were related to intestinal health. Furthermore, melatonin supplementation inverted the sleep deprivation-induced a decline of anti-inflammatory cytokines (IL-22) and an increase of the ROS and proinflammatory cytokines (IL-17) in jejunum. These findings suggested that melatonin, similar to a probiotics agent, can reverse sleep deprivation-induced small intestinal microbiota disorder by suppressing oxidative stress and inflammation response.

Growth associated polyhydroxybutyrate production by the novel Zobellellae tiwanensis strain DD5 from banana peels under submerged fermentation.

In view of environmental pollution by fossil fuel-based plastics, it has become imperative to find out an alternative biodegradable plastic for sustainability. In this context, polyhydroxy butyrate (PHB) production was carried out by the Zobellella sp. DD5 using inexpensive banana peels as the carbon source. Under optimized condition, 1.13 g/L (47.3%) of PHB was produced by the bacteria in growth associated mechanism. The CO group of PHB was detected from the high intense absorption band (1719 cm-1) of FTIR spectroscopic analysis. NMR and GC-MS results are also identical with the chemical shift signal CH, CH2 and CH3 group of PHB. The PHB is crystalline in nature and degree of crystallinity (Xc) - 34.38%, melting temperature (Tm) - 169 °C, thermal decomposition temperature (Td) - 248 °C as detected by XRD and DTA respectively. Rough surface morphology of PHB film was validated by AFM and SEM imaging that improves biodegradability of the PHB. The Young's modulus, tensile strength and elongation at break depicted hard and brittle nature of PHB. Fluorescence-activated cell sorting (FACS) confirmed cytocompatibility of PHB at 500 µg/mL in human embryonic kidney (HEK-293) cell line. The non-cytotoxic PHB can be used for various biomedical and agricultural applications in future.

Analysis of Zobellella denitrificans ZD1 draft genome: Genes and gene clusters responsible for high polyhydroxybutyrate (PHB) production from glycerol under saline conditions and its CRISPR-Cas system.

Polyhydroxybutyrate (PHB) is biodegradable and renewable and thus considered as a promising alternative to petroleum-based plastics. However, PHB production is costly due to expensive carbon sources for culturing PHB-accumulating microorganisms under sterile conditions. We discovered a hyper PHB-accumulating denitrifying bacterium, Zobellella denitrificans ZD1 (referred as strain ZD1 hereafter) capable of using non-sterile crude glycerol (a waste from biodiesel production) and nitrate to produce high PHB yield under saline conditions. Nevertheless, the underlying genetic mechanisms of PHB production in strain ZD1 have not been elucidated. In this study, we discovered a complete pathway of glycerol conversion to PHB, a novel PHB synthesis gene cluster, a salt-tolerant gene cluster, denitrifying genes, and an assimilatory nitrate reduction gene cluster in the ZD1 genome. Interestingly, the novel PHB synthesis gene cluster was found to be conserved among marine Gammaproteobacteria. Higher levels of PHB accumulation were linked to higher expression levels of the PHB synthesis gene cluster in ZD1 grown with glycerol and nitrate under saline conditions. Additionally, a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas type-I-E antiviral system was found in the ZD1 genome along with a long spacer list, in which most of the spacers belong to either double-stranded DNA viruses or unknown phages. The results of the genome analysis revealed strain ZD1 used the novel PHB gene cluster to produce PHB from non-sterile crude glycerol under saline conditions.

Aquatic bacterial contamination associated with sugarplant sewage outfalls as a microbial hazard for fish.

The aim of the study was to compare bacterial composition and load in waters and fish related to the wastewater treatment plant (WWTP), particularly waters and wild fish affected by sugarplant processing (sugar cane and sugar beet). Aeromonads were the most frequently isolated group from water and fish. A. hydrophila was a prevailing species in isolates from water, followed by A. veronii, Rheinheimera soli and Ochrobactrum anthropi. Of indicator bacteria for aquatic contamination from fish tissues, the most prominent were V. cholerae, Enterobacter cloacae and E. sakazakii. Sugar cane processing contributed to high viable cell counts at 37 °C while sugar beet processing contributed to high bacterial counts at 22 °C. Heterotrophs from gills of effluent fish were highest during sugar cane processing. Counts retrieved from fish skin were more uniform between effluent fish and fish from downstream waters. Antimicrobial resistance of bacteria isolated from water was high against amoxicillin, sulfamethoxazole, flumequine, norfloxacin and oxolinic acid in samples from the inflow of raw municipal wastewaters to WWTP, while resistance found in bacteria from the inflow of sugarplant mostly related to sulfamethoxazole and amoxicillin. The PCA analysis associated the occurrence of high heterotroph counts, P. aeruginosa, and intestinal enterococci on skin and gills with sugar cane, and yeasts and molds with sugar beet processing. Fish living in treated wastewaters and related water bodies could pose a microbial hazard if fished for human consumption, possibly causing infection when being handled and processed, as a risk of human pathogens penetrating fish tissues.

Characteristics of bacterial isolates in Swiss farmed and ornamental fish from a retrospective study from 2000 to 2017.

INTRODUCTION: Aquaculture is a rapidly growing field of food production of high economic importance. Bacterial infections are an important threat to aquaculture growth and also a common problem in ornamental fish. Some pathogenic agents and aquaculture production types are reported to be associated with increased disease. However, a detailed description of bacterial pathogens causing disease in Swiss aquaculture and ornamental pet fish is still missing. In this study we describe 1448 bacterial isolations originating from 1134 diagnostic laboratory submissions from farmed and ornamental fish in Switzerland for the period from 2000 to 2017. A strong seasonality was observed with submissions peaking in spring and summer. Bacterial isolations in fish submitted from organic farms were approximately six times more frequent than in conventional fish farms. Flavobacteriaceae, aeromonads and Yersinia ruckeri were the most common isolates from aquaculture, and motile aeromonads and Vibrio spp. were most often isolated from ornamental fish. The results of this study provide some interesting hypotheses, but further research is needed to better characterize risk factors for bacterial diseases in both aquaculture and aquarium fish in Switzerland.

INTRODUCTION: L'aquaculture est un secteur de la production alimentaire en pleine croissance et d'une grande importance économique. Les infections bactériennes constituent une menace importante pour la croissance de l'aquaculture mais également un problème courant chez les poissons d'ornement. Certains agents pathogènes et types de production aquacole seraient associés à une plus forte incidence de certaines maladies. Une description complète des agents pathogènes bactériens responsables de maladies chez les poissons d'élevage et d'ornement en Suisse fait cependant défaut. Nous décrivons dans cette étude 1448 isolats bactériens provenant de 1134 soumissions de poissons d'élevage et de poissons d'ornement en Suisse à un laboratoire de diagnostic entre 2000 et 2017. Une forte saisonnalité a été observée au printemps et en été. Les infections bactériennes chez les poissons de fermes biologiques étaient environ six fois plus fréquentes que dans les exploitations conventionnelles. Flavobacteriaceae, Aeromonas spp. et Yersinia ruckeri sont les isolats qui ont été les plus communément isolés des soumissions des piscicultures. Vibrio spp. ainsi que les espèces motiles d'Aeromonas spp. ont été les principaux isolats mis en évidence chez les poissons d'ornement. Les résultats de cette étude fournissent des hypothèses intéressantes, mais des recherches supplémentaires sont nécessaires pour mieux caractériser les facteurs de risque des maladies bactériennes chez les poissons d'aquaculture et d'aquarium en Suisse.

Dongshaea marina gen. nov., sp. nov., a facultatively anaerobic marine bacterium that ferments glucose with gas production.

Two isolates of heterotrophic, facultatively anaerobic, marine bacteria, designated DM1 and DM2T, were recovered from a lagoon sediment sample of Dongsha Island, Taiwan. Cells were Gram-reaction-negative rods. Nearly all of the cells were non-motile and non-flagellated during the late exponential to early stationary phase of growth, while a few of the cells exhibited motility with monotrichous flagellation. The two isolates required NaCl for growth and grew optimally at about 30 °C, 2-3 % NaCl and pH 7-8. They grew aerobically and could achieve anaerobic growth by fermenting d-glucose or other carbohydrates with production of acids and the gases, including CO2 and H2. Ubiquinone Q-8 was the only respiratory quinone. Cellular fatty acids were predominated by C16 : 0, C18 : 1ω7c and C16 : 1ω7c. The major polar lipid was phosphatidylethanolamine. Strains DM1 and DM2T had DNA G+C contents of 52.0 and 51.8 mol%, respectively, as determined by HPLC analysis. Phylogenetic analyses based on 16S rRNA gene sequences clearly indicated that the two isolates formed a distinct genus-level lineage in the family Aeromonadaceae of the class Gammaproteobacteria and was an outgroup with respect to a stable supragenic clade comprising species of the genera Oceanimonas, Oceanisphaera and Zobellella. The phylogenetic data and those from chemotaxonomic, physiological and morphological characterizations support the establishment of a novel species and genus inside the family Aeromonadaceae, for which the name Dongshaea marina gen. nov., sp. nov. is proposed. The type strain is DM2T (=BCRC 81069T=JCM 32096T).

Zobellella endophytica sp. nov., isolated from the roots of Phragmites communis in the Kumtag Desert.

A Gram-negative, aerobic, non-spore-forming, rod-shaped, motile bacterium, named strain 59N8T, was isolated from Phragmites communis roots in the Kumtag Desert. Phylogenetic analysis based on the 16S rRNA gene sequence showed that the isolate belongs to the genus Zobellella within the family Aeromonadaceae. The analysis showed that strain 59N8T was most closely related to Zobellella taiwanensis ZT1T. The average nucleotide identity value with Zobellella taiwanensis ZT1T was 88.2 %, and the digital DNA-DNA hybridization value was 29.7±2.4 %, which was calculated using the Genome-to-Genome Distance Calculator. The G+C content of strain 59N8T was 62.8 mol%. Strain 59N8T grew at 0-5 % (w/v) NaCl (optimum, 0-4 %), pH 6.0-9.0 (optimum, 7.0-8.0) and at 10-45 °C. The major cellular fatty acids were summed feature 8 (C18 : 1ω7c/C18 : 1ω6c), summed feature 3 (C16 : 1ω7c/C16 : 1ω6c) and C16 : 0. The major polar lipids in strain 59N8T were phosphatidylethanolamine and phosphatidylglycerol. Based on the chemotaxonomic, phylogenetic and phenotypic data, strain 59N8T represents a novel species in the genus Zobellella, for which the name Zobellellaendophytica sp. nov. is proposed. The type strain is 59N8T (=ACCC 60074T=KCTC 62456T).

[Isolation and Nitrogen Removal Characteristics of Salt-tolerant Heterotrophic Nitrification and Aerobic Denitrification Bacteria Zobellella sp. B307].

A heterotrophic nitrification and aerobic denitrification strain, B307, was isolated from the sediment of Jiaozhou Bay. The strain was identified by 16S rRNA sequence analysis, and its optimization condition and salt-tolerance characteristics were studied by single factor experiment. The denitrification effect in single or mixed nitrogen sources was investigated under optimum conditions. The results allowed the strain to be identified as Zobellella sp., based on 16S rRNA sequence analysis. The best carbon source was sodium succinate, and the optimum C/N was 5, the optimal initial pH was 9, and the optimal temperature was 35-40℃ respectively. After 12 hours, the NH4+-N and the NO3--N removal efficiencies were 98.35% and 99.75% in a mixed nitrogen source system. The removal efficiencies for NH4+-N and NO3--N were 97.67% and 94.39% within 24 hours when salinity was 75 g·L-1. The strain has highly efficient heterotrophic nitrification-aerobic denitrification ability and strong salt tolerance, which demonstrated that the strain has potential for extensive application for nitrogen removal in high salt wastewater.

Potential Anticoagulant Activity of Trypsin Inhibitor Purified from an Isolated Marine Bacterium Oceanimonas Sp. BPMS22 and its Kinetics.

Protease inhibitors control major biological protease activities to maintain physiological homeostasis. Marine bacteria isolated from oligotrophic conditions could be taxonomically distinct, metabolically unique, and offers a wide variety of biochemicals. In the present investigation, marine sediments were screened for the potential bacteria that can produce trypsin inhibitors. A moderate halotolerant novel marine bacterial strain of Oceanimonas sp. BPMS22 was isolated, identified, and characterized. The effect of various process parameters like salt concentration, temperature, and pH was studied on the growth of the bacteria and production of trypsin inhibitor. Further, the trypsin inhibitor was purified to near homogeneity using anion exchange, size exclusion, and affinity chromatography. The purified trypsin inhibitor was found to competitively inhibit trypsin activity with an inhibition coefficient, Ki, of 3.44 ± 0.13 µM and second-order association rate constant, kass, of 1.08 × 103 M-1 S-1. The proteinaceous trypsin inhibitor had a molecular weight of approximately 30 kDa. The purified trypsin inhibitor showed anticoagulant activity on the human blood samples.

Oceanimonas marisflavi sp. nov., a polycyclic aromatic hydrocarbon-degrading marine bacterium.

A Gram-stain-negative, strictly aerobic, motile and rod-shaped bacterial strain, designated 102-Na3T, was isolated from sediment of Sinduri beach in Taean, Republic of Korea. Strain 102-Na3T grew optimally at 28-37 °C, at pH 7.0-11.0 and in the presence of 1-3 % (w/v) NaCl, but NaCl was not an absolute requirement for growth. The neighbour-joining phylogenetic tree based on 16S rRNA gene sequences showed that strain 102-Na3T joined the clade comprising the type strains of Oceanimonasspecies. Strain 102-Na3T exhibited 16S rRNA gene sequence similarity values of 98.8, 98.3 and 98.0 % to the type strains of Oceanimonas doudoroffii MBIC1298T, Oceanimonas baumannii GB6T and Oceanimonas smirnovii 31-13T, respectively. Strain 102-Na3T contained summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0 and C12 : 0 as major fatty acids. The major quinone was ubiquinone-8. The polar lipids were composed of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol and two unidentified amino lipids. The DNA G+C content was 56.8 mol%. Strain 102-Na3T exhibited DNA-DNA relatedness values of 25.7, 21.7 and 14.8 % to the type strains of O. doudoroffii, O. baumannii and O. smirnovii, respectively. Differential phenotypic properties, together with its phylogenetic and genetic distinctiveness, revealed that strain 102-Na3T is separated from recognized species of the genus Oceanimonas. On the basis of the data presented, strain 102-Na3T (=KCTC 62271T=JCM 32358T=DSM 106032T) is considered the type strain of a novel species of the genus Oceanimonas, for which the name Oceanimonas marisflavi sp. nov. is proposed.

Modeling of growth kinetics for an isolated marine bacterium, Oceanimonas sp. BPMS22 during the production of a trypsin inhibitor.

Protease inhibitors significantly control physiologically relevant protease activities. Protease inhibitors from marine microbial sources are unique due to their rough living environmental conditions. In the present study, a protein protease inhibitor (PI) was produced from marine Oceanimonas sp. BPMS22. Seven different media were screened for the growth of the bacterium and production of PI. Different carbon and nitrogen sources were screened and optimized for the specific protease inhibitor activity. Three different growth models were checked for the best fit of the bacterial growth. A modified Gompertz model was selected as the best model for the growth of Oceanimonas sp. BPMS22 with the maximum specific growth rate of 0.165 hr-1 and doubling time of 4.2 hr. The production of PI takes place during the non-growing phase of the bacterial growth. A kinetic model for the production of PI during non-growing phase was used for studying various process parameters. From the model, the maximum trypsin inhibitor formation rate of 0.3802 IU per mg of biomass per hour was observed at 49.91 hr.

Zobellella maritima sp. nov., a polycyclic aromatic hydrocarbon-degrading bacterium, isolated from beach sediment.

A novel Gram-stain-negative, motile, rod-shaped bacterium, designated strain 102-Py4T, was isolated from Sinduri beach sediment in Taean, Republic of Korea. Cells were aerobic, oxidase-positive and catalase-positive. The isolate grew optimally with 1-3 % (w/v) NaCl, but NaCl is not an absolute requirement for growth. 16S rRNA gene sequence analysis revealed that strain 102-Py4T clustered together with Zobellella aerophila and fell within the clade formed by recognized species of the genus Zobellella. Its closest phylogenetic neighbours were Z. aerophila JC2671T (98.1 % 16S rRNA gene sequence similarity), Zobellella denitrificans ZD1T (96.4 %) and Zobellella taiwanensis ZT1T (96.0 %). The major fatty acids were summed feature 3 (comprising C16 : 1ω7c and/or C16 : 1ω6c), C12 : 0, summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c) and C16 : 0. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol and two unidentified amino lipids. The DNA G+C content was 62.1 mol%. The DNA-DNA relatedness value between strain 102-Py4T and Z. aerophila JC2671T was 12.4±1.3 %. The phenotypic properties of 102-Py4T demonstrated that this strain could be distinguished from other Zobellella species. On the basis of the data presented, strain 102-Py4T (=KCTC 62272T=JCM 32359T=DSM 106043T) is considered to represent a novel species of the genus Zobellella, for which the name Zobellella maritima sp. nov. is proposed.