Complete genome sequence and comparative genome analysis of Alcanivorax sp. IO_7, a marine alkane-degrading bacterium isolated from hydrothermally-influenced deep seawater of southwest Indian ridge.

Genome of Alcanivorax sp. IO_7, an alkane degrading deep-sea bacteria isolated from hydrothermally-influenced Southwest Indian Ridge was sequenced and analysed. Genomic data mining revealed gene clusters for degrading n-alkane and cycloalkanes, including biosurfactant production. The strain was shown to grow on hexadecane as its sole carbon source, supporting the findings of genomic analysis. Presence of cyclohexanone monooxygenase among genomic islands suggest that this strain may have used gene transfer to enhance its hydrocarbon degradation ability. Genes encoding for heavy metal resistance, multidrug resistance and multiple natural product biosynthesis crucial for survival in the hydrothermally influenced deep sea environment were detected. In our comparative genome analysis, it was evident that marine Alcanivorax strains contain a suite of enzymes for n-alkane and haloalkanoate degradation. Comparative genome and genomic synteny analysis provided insights into the physiological features and adaptation strategies of Alcanivorax sp. IO_7 in the deep-sea hydrothermal environment.

Ketobacter nezhaii sp. nov., a marine bacterium isolated from coastal sediment.

A Gram-stain-negative, motile, aerobic and heterotrophic bacterium, designated as GYS_M3HT, was isolated from marine coastal sediment sampled at Xiamen Island. Cells were rod-shaped with one polar flagellum and weakly positive for oxidase and catalase. Growth of the strain occurred at pH 6-9 (optimum, pH 7-8), at 15-37 °C (optimum, 28 °C) and with NaCl concentrations of 1.0-6.0 % (optimum, 2.0 %). It had highest 16S rRNA similarity (97.7 %) to Ketobacter alkanivorans GI5T, followed by the members of the genus Alcanivorax (lower than 91.2 %). The results of phylogenetic analysis indicated that it belonged to the genus Ketobacter within the family Alcanivoracaceae. In addition, the average nucleotide identity and digital DNA-DNA hybridization values between strain GYS_M3HT and K. alkanivorans GI5T were 71.4 and 19.7 %, respectively, indicating that strain GYS_M3HT belonged to a novel species. Its genome consisted of 5 318 758 bp, with a genomic DNA G+C content of 50.0 mol%. The respiratory quinone was Q-8 and the dominant fatty acids were identified as iso-C15 : 0 (25.4 %), C16 : 1 ω6c/C16 : 1 ω7c (14.4 %) and iso-C13 : 0 (7.2 %). The main polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Therefore, based on phenotypic, chemotaxonomic and phylogenetic results, strain GYS_M3HT represents a novel species within the genus Ketobacter, for which the name Ketobacter nezhaii sp. nov. is proposed, with the type strain GYS_M3HT (=MCCC 1A13808T=KCTC 72247T).

Alcanivorax sediminis sp. nov., isolated from deep-sea sediment of the Pacific Ocean.

A taxonomic study was carried out on strain PA15-N-34T, which was isolated from deep-sea sediment of Pacific Ocean. The bacterium was Gram-stain-positive, oxidase- and catalase-positive and rod-shaped. Growth was observed at salinity of 0-15.0% NaCl and at temperatures of 10-45 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain PA15-N-34T belonged to the genus Alcanivorax, with the highest sequence similarity to Alcanivorax profundi MTEO17T (97.7 %), followed by Alcanivorax nanhaiticus 19 m-6T (97.3 %) and 12 other species of the genus Alcanivorax (93.4 %-97.0 %). The average nucleotide identity and DNA-DNA hybridization values between strain PA15-N-34T and type strains of the genus Alcanivorax were 71.46-81.78% and 18.7-25.2 %, respectively. The principal fatty acids (>10 %) were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 31.2 %), C16 : 0 (25.0 %) and summed feature 3 (14.6 %). The DNA G+C content was 57.15 mol%. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, four unidentified aminolipids and three unidentified lipids. The novel strain can be differentiated from its closest type strain by a negative test for urease and the presence of diphosphatidylglycerol and aminolipid. The combined genotypic and phenotypic data show that strain PA15-N-34T represents a novel species within the genus Alcanivorax, for which the name Alcanivorax sediminis sp. nov. is proposed, with the type strain PA15-N-34T (=MCCC 1A14738T=KCTC 72163T).

Genomic features and copper biosorption potential of a new Alcanivorax sp. VBW004 isolated from the shallow hydrothermal vent (Azores, Portugal).

A new Alcanivorax sp. VBW004 was isolated from a shallow hydrothermal vent in Azores Island, Portugal. In this study, we determined VBW004 was resistant to copper. This strain showed maximum tolerance of copper concentrations up to 600 µg/mL. Based on 16S rRNA gene sequencing and phylogeny revealed that this strain was more closely related to Alcanivorax borkumensis SK2. We sequenced the genome of this strain that consist of 3.8 Mb size with a G + C content of 58.4 %. In addition, digital DNA-DNA hybridizations (dDDH) and the average nucleotide identities (ANI) analysis between Alcanivorax borkumensis SK2 and Alcanivorax jadensis T9 revealed that Alcanivorax sp. VBW004 belongs to new species. Functional annotation revealed that the genome acquired multiple copper resistance encoding genes that could assist VBW004 to respond to high Cu toxicity. Our results from biosorption analysis presumed that the VBW004 is an ecologically important bacterium that could be useful for copper bioremediation.

Marinicella rhabdoformis sp. nov., isolated from coastal sediment.

A Gram-stain-negative, rod-shaped, facultative anaerobic bacterium, designated strain 3539T, was isolated from coastal sediment of Weihai, PR China. Optimal growth occurred at 28 °C, pH 7.5-8.0 and in the presence of 3.0 % (w/v) NaCl. Results of phylogenetic analysis based on 16S rRNA gene sequences revealed that strain 3539T formed a robust clade with members of the genus Marinicella and was closely related to Marinicella litoralis JCM 16154T, Marinicella sediminis F2T and Marinicella pacifica sw153T with 97.7, 96.2 and 95.4 % sequence similarity, respectively. The average amino acid identity, percentage of conserved proteins, average nucleotide identity and digital DNA-DNA hybridization values between strain 3539T and M. litoralis JCM 16154T were 64.9, 68.3, 72.8 and 18.9 %, respectively. The genomic DNA G+C content of strain 3539T was 42.0 mol%. The dominant respiratory quinone was ubiquinone-8, and the major fatty acids were iso-C15 : 0 and summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c). The polar lipids of strain 3539T consisted of phosphatidyldimethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unidentified aminophospholipid, one unidentified lipid and three unidentified phospholipids. Based on the combination of phylogenetic, phenotypic and chemotaxonomic data, strain 3539T is considered to represent a novel species within the genus Marinicella in he family Alcanivoracaceae, for which the name Marinicella rhabdoformis sp. nov. is proposed. The type strain of the new species is 3539T (=KCTC 72414T=MCCC 1H00388T).

Alcanivorax profundi sp. nov., isolated from deep seawater of the Mariana Trench.

A Gram-stain-negative, rod-shaped, non-motile, strictly aerobic strain, designated as MTEO17T, was isolated from a 1000 m deep seawater sample of the Mariana Trench. Growth was observed at 10-45 °C (optimum, 37 °C), in the presence of 0.0-12.0 % NaCl (w/v; optimum, 3.0 %) and at pH 6.0-10.0 (optimum, pH 7.0-8.0). Phylogenetic analysis, based on the 16S rRNA gene sequence, revealed that strain MTEO17T belonged to the genus Alcanivorax and showed the highest sequence similarity of 97.9 % to Alcanivorax nanhaiticus MCCC 1A05629T. The estimated average nucleotide identity and DNA-DNA hybridization values between strain MTEO17T and A. nanhaiticus MCCC 1A05629T were 78.98 and 23.80 %, respectively. The significant dominant fatty acids were C16 : 0, summed feature 8 (C18 : 1ω6c and/or C18 : 1ω7c) and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The polar lipids comprised two phosphatidylethanolamines, one phosphatidylglycerol, one unidentified phospholipid and four unidentified polar lipids. The DNA G+C content of strain MTEO17T was 57.5 %. On the basis of the polyphasic evidence, strain MTEO17T is proposed to represent a novel species of the genus Alcanivorax, for which the name Alcanivorax profundi sp. nov. is proposed. The type strain is MTEO17T (=KCTC 52694T=MCCC 1K03252T).

Periodic and Spatial Spreading of Alkanes and Alcanivorax Bacteria in Deep Waters of the Mariana Trench.

In subduction zones, serpentinization and biological processes may release alkanes to the deep waters, which would probably result in the rapid spread of Alcanivorax However, the timing and area of the alkane distribution and associated enrichment of alkane-degrading microbes in the dark world of the deep ocean have not been explored. In this study, we report the richness (up to 17.8%) of alkane-degrading bacteria, represented by Alcanivorax jadensis, in deep water samples obtained at 3,000 to 6,000 m in the Mariana Trench in two cruises. The relative abundance of A. jadensis correlated with copy numbers of functional almA and alkB genes, which are involved in alkane degradation. In these water samples, we detected a high flux of alkanes, which probably resulted in the prevalence of A. jadensis in the deep waters. Contigs of A. jadensis were binned from the metagenomes for examination of alkane degradation pathways and deep sea-specific pathways, which revealed a lack of nitrate and nitrite dissimilatory reduction in our A. jadensis strains. Comparing the results for the two cruises conducted close to each other, we suggest periodic release of alkanes that may spread widely but periodically in the trench. Distribution of alkane-degrading bacteria in the world's oceans suggests the periodic and remarkable contributions of Alcanivorax to the deep sea organic carbon and nitrogen sources.IMPORTANCE In the oligotrophic environment of the Mariana Trench, alkanes as carbohydrates are important for the ecosystem, but their spatial and periodic spreading in deep waters has never been reported. Alkane-degrading bacteria such as Alcanivorax spp. are biological signals of the alkane distribution. In the present study, Alcanivorax was abundant in some waters, at depths of up to 6,000 m, in the Mariana Trench. Genomic, transcriptomic, and chemical analyses provide evidence for the presence and activities of Alcanivorax jadensis in deep sea zones. The periodic spreading of alkanes, probably from the subductive plates, might have fundamentally modified the local microbial communities, as well as perhaps the deep sea microenvironment.

Alcanivorax indicus sp. nov., isolated from seawater.

A Gram-stain-negative, motile, rod-shaped bacterium, designated SW127T, was isolated from a seawater sample collected from the Indian Ocean. Strain SW127T was aerobic, catalase- and oxidase-positive, and grew at 8-42 °C (optimum, 30 °C), at pH 5.5-9.0 (optimum, pH 7.5) and in the presence of 0.5-11.0 % (w/v) NaCl (optimum, 3.0-4.0 %). Comparative analysis of 16S rRNA gene sequences indicated that strain SW127T belonged to the genus Alcanivorax, and closely related to Alcanivorax pacificus MCCC 1A00474T (96.7 % sequence similarity). The predominant cellular fatty acids of strain SW127T were C16 : 0 and summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c). Strain SW127T contained phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids. The genomic DNA G+C content of strain SW127T was 62.8 mol%. On the basis of its phenotypic characteristics and phylogenetic data, strain SW127T represents a novel species of the genus Alcanivorax, for which the name Alcanivorax indicus sp. nov. is proposed. The type strain is SW127T (=CGMCC 1.16233T=KCTC 62652T).

Marinicella sediminis sp. nov., isolated from marine sediment.

A novel heterotrophic, Gram-stain-negative, aerobic, rod-shaped, pale yellow, non-motile and non-spore-forming bacterium, designated strain F2T, was isolated from marine sediment collected from the Weihai coast, Shandong Province, PR China. Optimal growth occurred at 33 °C (range, 10-37 °C), with 3.0-4.0 % (w/v) NaCl (1.0-8.0 %) and at pH 7.5-8.0 (pH 6.5-9.0). Q-8 was the sole respiratory quinone. The major polar lipids of strain F2T were phosphatidylmonomethylethanolamine, phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, two unidentified phospholipids and two unidentified polar lipids. The major cellular fatty acid in strain F2T was iso-C15 : 0. The genomic DNA G+C content of the strain was 48.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequencing revealed that strain F2T is most closely related to Marinicella litoralis JCM 16154T (97.5 %) and Marinicella pacifica sw153T (96.0 %). Based on the results of our polyphasic analysis, we conclude that strain F2T represents a novel species of the genus Marinicella, for which the name Marinicella sediminis sp. nov. is proposed. The type strain of the new species is F2T (=KCTC 42953T=MCCC 1H00149T).

Ketobacter alkanivorans gen. nov., sp. nov., an n-alkane-degrading bacterium isolated from seawater.

Strain GI5T was isolated from a surface seawater sample collected from Garorim Bay (West Sea, Republic of Korea). The isolated strain was aerobic, Gram-stain-negative, rod-shaped, motile by means of a polar flagellum, negative for catalase and weakly positive for oxidase. The optimum growth pH, salinity and temperature were determined to be pH 7.5-8.0, 3 % NaCl (w/v) and 25 °C, respectively; the growth ranges were pH 6.0-9.0, 1-7 % NaCl (w/v) and 18-40 °C. The results of phylogenetic analysis of 16S rRNA gene sequences indicated that GI5T clustered within the family Alcanivoracaceae, and most closely with Alcanivorax dieseloleiB-5T and Alcanivorax marinusR8-12T (91.9 % and 91.6 % similarity, respectively). The major cellular fatty acids in GI5T were C18 : 1ω7c/C18 : 1ω6c (44.45 %), C16 : 1ω6c/C16 : 1ω7c (14.17 %) and C16 : 0 (10.19 %); this profile was distinct from those of the closely related species. The major respiratory quinone of GI5T was Q-8. The main polar lipids were phosphatidylethanolamine and phosphatidylglycerol. Two putative alkane hydroxylase (alkB) genes were identified in GI5T. The G+C content of the genomic DNA of GI5T was determined to be 51.2 mol%. On the basis of the results of phenotypic, chemotaxonomic and phylogenetic studies, strain GI5T represents a novel species of a novel genus of the family Alcanivoracaceae, for which we propose the name Ketobacter alkanivorans gen. nov., sp. nov.; the type strain is GI5T (=KCTC 52659T=JCM 31835T).

Alcanivorax mobilis sp. nov., a new hydrocarbon-degrading bacterium isolated from deep-sea sediment.

A taxonomic study was carried out on strain MT13131T, which was isolated from deep-sea sediment of the Indian Ocean during the screening of oil-degrading bacteria. The chain length range of n-alkanes (C8 to C32) oxidized by strain MT13131T was determined in this study. The bacterium was Gram-negative, oxidase- and catalase-positive, single rod shaped, and motile by peritrichous flagella. Growth was observed at salinities of 1-12 % and at temperatures of 10-42 °C. The isolate was capable of Tween 20, 40 and 80 hydrolysis, but incapable of gelatin, cellulose or starch hydrolysis. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain MT13131T belonged to the genus Alcanivorax, with highest sequence similarity to Alcanivorax marinus R8-12T (96.92 %), other species of genus Alcanivorax shared 92.96-96.69 % sequence similarity. The principal fatty acids were summed feature 3 (C16 : 1ω6c/ω7c), summed feature 8 (C18 : 1ω7c/ω6c), C16 : 0 and C12 : 0 3OH. The G+C content of the chromosomal DNA was 64.2 mol%. Phosphatidylglycerol, phosphatidylethanolamine, three aminolipids and three phospholipids were present. The combined genotypic and phenotypic data showed that strain MT13131T represents a novel species within the genus Alcanivorax, for which the name Alcanivorax mobilis sp. nov. is proposed, with the type strain MT13131T (=MCCC 1A11581T=KCTC 52985T).

Periodically spilled-oil input as a trigger to stimulate the development of hydrocarbon-degrading consortia in a beach ecosystem.

In this study, time-series samples were taken from a gravel beach to ascertain whether a periodic oil input induced by tidal action at the early stage of an oil spill can be a trigger to stimulate the development of hydrocarbon-degrading bacteria under natural in situ attenuation. High-throughput sequencing shows that the microbial community in beach sediments is characterized by the enrichment of hydrocarbon-degrading bacteria, including Alcanivorax, Dietzia, and Marinobacter. Accompanying the periodic floating-oil input, dynamic successions of microbial communities and corresponding fluctuations in functional genes (alkB and RDH) are clearly indicated in a time sequence, which keeps pace with the ongoing biodegradation of the spilled oil. The microbial succession that accompanies tidal action could benefit from the enhanced exchange of oxygen and nutrients; however, regular inputs of floating oil can be a trigger to stimulate an in situ "seed bank" of hydrocarbon-degrading bacteria. This leads to the continued blooming of hydrocarbon-degrading consortia in beach ecosystems. The results provide new insights into the beach microbial community structure and function in response to oil spills.

Diversity and antimicrobial activity of bacteria isolated from different Brazilian coral species.

Corals harbor a wide diversity of bacteria associated with their mucus. These bacteria can play an important role in nutrient cycling, degradation of xenobiotics and defense against pathogens by producing antimicrobial compounds. However, the diversity of the cultivable heterotrophic bacteria, especially in the Brazilian coral species, remains poorly understood. The present work compares the diversity of cultivable bacteria isolated from the mucus and surrounding environments of four coral species present along the Brazilian coast, and explores the antibacterial activity of these bacteria. Bacteria belonging to the phyla Proteobacteria, Firmicutes, Actinobacteria and Bacteroidetes were isolated. The mucus environment presented a significantly different bacteria composition, compared to the water and sediment environments, with high abundance of Alcanivorax, Acinetobacter, Aurantimonas and Erythrobacter. No difference in the inhibition activity was found between the isolates from mucus and from the surrounding environment. Eighty-three per cent of the bacteria isolated from the mucus presented antimicrobial activity against Serratia marcescens, an opportunistic coral pathogen, suggesting that they might play a role in maintaining the health of the host. Most of the bacteria isolates that presented positive antimicrobial activity belonged to the genus Bacillus.

Alcanivorax nanhaiticus sp. nov., isolated from deep sea sediment.

A taxonomic study was carried out on strain 19-m-6T, which was isolated from deep sea sediment of the South China Sea during the screening of alkane-degrading bacteria. The isolate was Gram-reaction-negative, and oxidase- and catalase- positive. On the basis of 16S rRNA gene sequence similarity, strain 19-m-6T was shown to belong to the genus Alcanivorax, related to Alcanivorax jadensis T9T (97.5 %), Alcanivorax hongdengensis A-11-3T (97.3 %), A. lcanivorax borkumensis SK2T (96.6 %) and seven other species of the genus Alcanivorax(93.9-95.4 %). Average nucleotide identity values between strain 19-m-6T and A. jadensis T9T, A. hongdengensis A-11-3T and A. borkumensis SK2T were 85.12, 85.87 and 84.35 %, respectively. The estimated DNA-DNA hybridization values between strain 19-m-6T and these three type strains were 22.0, 22.6 and 21.2 %, respectively. Four alkane hydroxylase (alkB) genes were obtained from the draft genome sequence. The G+C content of the chromosomal DNA was 56.44 mol%. The major fatty acids were C16 : 0, C18 : 1ω7c and summed feature 3 (C16 : 1ω6c and/or C16 : 1ω7c). The polar lipids were phosphatidylglycerol, phosphatidylethanolamine, one aminolipid, three phospholipids, two glycolipids and two aminophospholipids. According to its phenotypic features, fatty acid composition and 16S rRNA gene sequence, the novel strain fitted well into the genus Alcanivorax, but could be clearly distinguished from all other known Alcanivorax species described to date. The nameAlcanivorax nanhaiticus sp. nov. is thus proposed, with 19-m-6T (=MCCC 1A05629T=KCTC 52137T) as the type strain.

Biodegradation of crude oil by individual bacterial strains and a mixed bacterial consortium.

Three bacterial isolates identified as Alcanivorax borkumensis SK2, Rhodococcus erythropolis HS4 and Pseudomonas stutzeri SDM, based on 16S rRNA gene sequences, were isolated from crude oil enrichments of natural seawater. Single strains and four bacterial consortia designed by mixing the single bacterial cultures respectively in the following ratios: (Alcanivorax: Pseudomonas, 1:1), (Alcanivorax: Rhodococcus, 1:1), (Pseudomonas: Rhodococcus, 1:1), and (Alcanivorax: Pseudomonas: Rhodococcus, 1:1:1), were analyzed in order to evaluate their oil degrading capability. All experiments were carried out in microcosms systems containing seawater (with and without addition of inorganic nutrients) and crude oil (unique carbon source). Measures of total and live bacterial abundance, Card-FISH and quali-, quantitative analysis of hydrocarbons (GC-FID) were carried out in order to elucidate the co-operative action of mixed microbial populations in the process of biodegradation of crude oil. All data obtained confirmed the fundamental role of bacteria belonging to Alcanivorax genus in the degradation of linear hydrocarbons in oil polluted environments.

Biodegradation of crude oil by individual bacterial strains and a mixed bacterial consortium

Three bacterial isolates identified as Alcanivorax borkumensis SK2, Rhodococcus erythropolis HS4 and Pseudomonas stutzeri SDM, based on 16S rRNA gene sequences, were isolated from crude oil enrichments of natural seawater. Single strains and four bacterial consortia designed by mixing the single bacterial cultures respectively in the following ratios: (Alcanivorax: Pseudomonas, 1:1), (Alcanivorax: Rhodococcus, 1:1), (Pseudomonas: Rhodococcus, 1:1), and (Alcanivorax: Pseudomonas: Rhodococcus, 1:1:1), were analyzed in order to evaluate their oil degrading capability. All experiments were carried out in microcosms systems containing seawater (with and without addition of inorganic nutrients) and crude oil (unique carbon source). Measures of total and live bacterial abundance, Card-FISH and quali-, quantitative analysis of hydrocarbons (GC-FID) were carried out in order to elucidate the co-operative action of mixed microbial populations in the process of biodegradation of crude oil. All data obtained confirmed the fundamental role of bacteria belonging to Alcanivorax genus in the degradation of linear hydrocarbons in oil polluted environments.

Alcanivorax gelatiniphagus sp. nov., a marine bacterium isolated from tidal flat sediments enriched with crude oil.

A Gram-reaction-negative, rod-shaped marine bacterium, designated MEBiC08158(T), was isolated from sediments collected from Taean County, Korea, near the Hebei Spirit tanker oil spill accident. 16S rRNA gene sequence analysis revealed that strain MEBiC08158(T) was closely related to Alcanivorax marinus R8-12(T) (99.5% similarity) but was distinguishable from other members of the genus Alcanivorax (93.7-97.1%). The DNA-DNA hybridization value between strain MEBiC08158(T) and A. marinus R8-12(T) was 58.4%. Growth of strain MEBiC08158(T) was observed at 15-43 °C (optimum 37-40 °C), at pH 6.0-9.5 (optimum pH 7.0-8.0) and with 0.5-16% NaCl (optimum 1.5-3.0%). The dominant fatty acids were C16 : 0, C19 : 0 cyclo ω8c, C12 : 0, C18 : 1ω7c, C12 : 0 3-OH and summed feature 3 (comprising C15 : 0 2-OH and/or C16 : 1ω7c). Several phenotypic characteristics differentiate strain MEBiC08158(T) from phylogenetically close members of the genus Alcanivorax. Therefore, strain MEBiC08158(T) should be classified as representing a novel species of the genus Alcanivorax, for which the name Alcanivorax gelatiniphagus sp. nov. is proposed. The type strain is MEBiC08158(T) ( = KCCM 42990(T) = JCM 18425(T)).

Kangiella profundi sp. nov., isolated from deep-sea sediment.

A taxonomic study employing a polyphasic approach was carried out on strain FT102(T), which was isolated from a deep-sea sediment sample collected in the south-west Indian Ocean at a depth of 2784 m. The strain was Gram-stain-negative, non-motile, rod-shaped and non-spore-forming. It grew optimally at 37-42 °C, pH 6.5-8.5 and in the presence of 1-4% (w/v) NaCl. Phylogenetic analysis of 16S rRNA gene sequences confirmed the separation of the novel strain from recognized members of the genus Kangiella that are available in public databases. Strain FT102(T) exhibited 95.5-98.6% 16S rRNA gene sequence similarity to the type strains of the eight recognized species of the genus Kangiella. The chemotaxonomically characteristic fatty acid iso-C15:0 and ubiquinone Q-8 were also detected. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylmonomethylethanolamine. The DNA G + C content of strain FT102(T) was 45.0 mol%. The mean DNA-DNA relatedness values between strain FT102(T) and the type strains of Kangiella aquimarina and Kangiella koreensis were 47.3% and 13.7%, respectively. The combined results of phylogenetic, physiological and chemotaxonomic studies indicated that strain FT102(T) was affiliated with the genus Kangiella but differed from the recognized species of the genus Kangiella. Therefore, strain FT102T represents a novel species of the genus Kangiella, for which the name Kangiella profundi sp. nov. is proposed. The type strain is FT102(T) ( = CGMCC 1.12959(T) = KCTC 42297(T) = JCM 30232(T)).

Characterization of alcohol dehydrogenase from Kangiella koreensis and its application to production of all-trans-retinol.

A recombinant alcohol dehydrogenase (ADH) from Kangiella koreensis was purified as a 40 kDa dimer with a specific activity of 21.3 nmol min(-1) mg(-1), a K m of 1.8 µM, and a k cat of 1.7 min(-1) for all-trans-retinal using NADH as cofactor. The enzyme showed activity for all-trans-retinol using NAD (+) as a cofactor. The reaction conditions for all-trans-retinol production were optimal at pH 6.5 and 60 °C, 2 g enzyme l(-1), and 2,200 mg all-trans-retinal l(-1) in the presence of 5% (v/v) methanol, 1% (w/v) hydroquinone, and 10 mM NADH. Under optimized conditions, the ADH produced 600 mg all-trans-retinol l(-1) after 3 h, with a conversion yield of 27.3% (w/w) and a productivity of 200 mg l(-1) h(-1). This is the first report of the characterization of a bacterial ADH for all-trans-retinal and the biotechnological production of all-trans-retinol using ADH.

Alcanivorax xenomutans sp. nov., a hydrocarbonoclastic bacterium isolated from a shrimp cultivation pond.

Two bacterial strains (JC109(T) and JC261) were isolated from a sediment sample collected from a shrimp cultivation pond in Tamil Nadu (India). Cells were Gram-stain-negative, motile rods. Both strains were positive for catalase and oxidase, hydrolysed Tween 80, and grew chemo-organoheterotrophically with an optimal pH of 6 (range pH 4-9) and at 30 °C (range 25-40 °C). Based on 16S rRNA gene sequence analysis, strains JC109(T) and JC261 were identified as belonging to the genus Alcanivorax with Alcanivorax dieselolei B-5(T) (sequence similarity values of 99.3 and 99.7%, respectively) and Alcanivorax balearicus MACL04(T) (sequence similarity values of 98.8 and 99.2%, respectively) as their closest phylogenetic neighbours. The 16S rRNA gene sequence similarity between strains JC109(T) and JC261 was 99.6%. The level of DNA-DNA relatedness between the two strains was 88%. Strain JC109(T) showed 31 ± 1 and 26 ± 2% DNA-DNA relatedness with A. dieselolei DSM 16502(T) and A. balearicus DSM 23776(T), respectively. The DNA G+C content of strains JC109(T) and JC261 was 54.5 and 53.4 mol%, respectively. Polar lipids of strain JC109(T) included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unidentified aminophospholipids, two unidentified phospholipids and two unidentified lipids. The major fatty acids were C10:0, C12:0, C16:0, C12:0 3-OH, C16:1ω7c, C18:1ω7c and C19:0 cyclo ω8c. Both strains could utilize diesel oil and a variety of xenobiotics as carbon and energy sources. The results of physiological, biochemical, chemotaxonomic and molecular analyses allowed the clear differentiation of strains JC109(T) and JC261 from all other members of the genus Alcanivorax. Strains JC109(T) and JC261 are thus considered to represent a novel species, for which the name Alcanivorax xenomutans sp. nov. is proposed. The type strain is JC109(T) ( = KCTC 23751(T) = NBRC 108843(T)).