High synthetic cost-amino acids reduce member interactions of acetate-degrading methanogenic microbial community.

Introduction: The cooperation among members of microbial communities based on the exchange of public goods such as 20 protein amino acids (AAs) has attracted widespread attention. However, little is known about how AAs availability affects interactions among members of complex microbial communities and the structure and function of a community. Methods: To investigate this question, trace amounts of AAs combinations with different synthetic costs (low-cost, medium-cost, high-cost, and all 20 AAs) were supplemented separately to acetate-degrading thermophilic methanogenic reactors, and the differences in microbial community structure and co-occurring networks of main members were compared to a control reactor without AA supplementation. Results: The structure of the microbial community and the interaction of community members were influenced by AAs supplementation and the AAs with different synthetic costs had different impacts. The number of nodes, links, positive links, and the average degree of nodes in the co-occurrence network of the microbial communities with AAs supplementation was significantly lower than that of the control without AAs supplementation, especially for all 20 AAs supplementation followed by the medium- and high-cost AAs supplementation. The average proportion of positive interactions of microbial members in the systems supplemented with low-cost, medium-cost, high-cost, all AAs, and the control group were 0.42, 0.38, 0.15, 0.4, and 0.45, respectively. In addition, the ecological functions of community members possibly changed with the supplementation of different cost AAs. Discussion: These findings highlight the effects of AAs availability on the interactions among members of complex microbial communities, as well as on community function.

Evaluation of physicochemical properties, bacterial community, and product fertility during rice straw composting supplemented with different nitrogen-rich wastes.

This study evaluated the compostability of rice straw as the main feedstock (75 % in dry weight), supplemented with three different nitrogen-rich wastes, namely food waste (FW), dairy manure (DM), and sewage sludge (SS). Organic matter (OM) degradation, maturity and fertility of the end-product, and bacterial community structure during the composting processes were compared. All composting processes generated mature end-product within 51 days. Notably, FW addition was more effective to accelerate rice straw OM degradation and significantly improved end-product fertility with a high yield of Chinese cabbage. The succession of the bacterial community was accelerated with FW supplementation. Genera Geobacillus, Chryseolinea, and Blastocatella were significantly enriched during the composting of rice straw with FW supplementation. Finally, temperature, total nitrogen, moisture, pH, and total carbon were the key factors affecting microorganisms. This study provides a promising alternative method to enhance the disposal of larger amounts of rice straw in a shorter time.

Microbial communities in crude oil phase and filter-graded aqueous phase from a Daqing oilfield after polymer flooding.

AIMS: The aim was to characterize indigenous micro-organisms in oil reservoirs after polymer flooding (RAPF). METHODS: The microbial communities in the crude oil phase (Oil) and in the filter-graded aqueous phases Aqu0.22 (>0.22 µm) and Aqu0.1 (0.1-0.22 µm) were investigated by 16S rRNA gene high-throughput sequencing. RESULTS: Indigenous micro-organisms related to hydrocarbon degradation prevailed in the three phases of each well. However, obvious differences in bacterial compositions were observed amongst the three phases of the same well and amongst the same phase of different wells. The crude oil and Aqu0.22 shared many dominant bacteria. Aqu0.1 contained a unique bacterial community in each well. Most bacteria in Aqu0.1 were affiliated to culturable genera, suggesting that they may adapt to the oil reservoir environment by reduction of cell size. Contrary to the bacterial genera, archaeal genera were similar in the three phases but varied in relative abundances. The observed microbial differences may be driven by specific environmental factors in each oil well. CONCLUSIONS: The results suggest an application potential of microbial enhanced oil recovery (MEOR) technology in RAPF. The crude oil and Aqu0.1 contain many different functional micro-organisms related to hydrocarbon degradation. Both should not be overlooked when investing and exploring the indigenous micro-organisms for MEOR. SIGNIFICANCE AND IMPACT OF THE STUDY: This work facilitates the understanding of microbial community structures in RAPF and provides information for microbial control in oil fields.

The complete genome of Dietzia timorensis ID05-A0528T revealed the genetic basis for its saline-alkali tolerance.

The type strain Dietzia timorensis ID05-A0528T, was reported to be able to survive in the highly saline and alkaline environments with diverse carbon sources. In order to more pertinently understand the genetic mechanisms of its environmental tolerance and crude oil emulsification, we reported the complete genome sequence of the strain in the study. The genome contains only one circular chromosome, with the total size of 3,607,892 bps, and the G+C content of this strain is 65.58%, much lower than other type strains of this genus. It was found that strain ID05-A0528T contains genes involved in transportation and biosynthesis of compatible solutes, as well as genes encoding monovalent cation/proton antiporters, which could explain its abilities to tolerate high salinity and alkalinity. Various central metabolic routes and complete alkane hydroxylation pathway were also identified in the genome of strain ID05-A0528T, which is in accordance with its ability to use a wide spectrum of carbon sources and to degrade n-alkanes.

Crude oil as a microbial seed bank with unexpected functional potentials.

It was widely believed that oil is a harsh habitat for microbes because of its high toxicity and hydrophobicity. However, accumulating evidence has revealed the presence of live microbes in crude oil. Therefore, it's of value to conduct an in-depth investigation on microbial communities in crude oil. To this end, microorganisms in oil and water phases were collected from four oil-well production mixtures in Qinghai Oilfield, China, and analyzed for their taxonomic and functional compositions via pyrosequencing and GeoChip, respectively. Hierarchical clustering of 16S rRNA gene sequences and functional genes clearly separated crude oil and water phases, suggestive of distinct taxonomic and functional gene compositions between crude oil and water phases. Unexpectedly, Pseudomonas dominated oil phase where diverse functional gene groups were identified, which significantly differed from those in the corresponding water phases. Meanwhile, most functional genes were significantly more abundant in oil phase, which was consistent with their important roles in facilitating survival of their host organisms in crude oil. These findings provide strong evidence that crude oil could be a "seed bank" of functional microorganisms with rich functional potentials. This offers novel insights for industrial applications of microbial-enhanced oil recovery and bioremediation of petroleum-polluted environments.

Negadavirga shengliensis gen. nov., sp. nov., a novel member of the family Cyclobacteriaceae isolated from oil-contaminated saline soil.

Four novel Gram-stain-negative, rod-shaped, and non-motile bacterial strains, SLG210-21(T), SLG210-4, SLG210-5 and SLG210-14, were isolated from oil-contaminated saline soil in Shengli Oilfield, China. Growth were observed at 25-42 °C (optimum 37 °C), in the presence of 0-10 % (w/v) NaCl (optimum 0-1 %) and at pH 4.0-10.0 (optimum pH 7.6-8.6). All the strains were positive for catalase and α, ß-galactosidase activities and nitrogen reduction, and negative for oxidase activity, glucose fermentation and hydrolysis of agar, starch, gelatin, Tween 40, 60 and 80. The DNA G+C contents of the four strains were 41.3-43.0 mol% and the predominant respiratory quinones were all menaquinone-7. The major fatty acids were iso-C15:0, anteiso-C15:0, summed feature 3 (C16:1 ω7c and/or C16:1 ω6c), C16:1 ω5c and summed feature 9 (iso-C17:1 ω9c and/or 10-methyl C16:0), while the polar lipids consisted of phosphatidylcholine, phosphatidylethanolamine, glycolipid, two unidentified phospholipids and two unidentified amino lipids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the four strains clustered together to form a stable branch in the family Cyclobacteriaceae, and were most closely related to the genera Cyclobacterium and Echinicola with the 16S rRNA gene sequence similarities being 88.6-90.3 and 89.6-91.4 %, respectively. DNA-DNA hybridization between SLG210-21(T) and the other three strains showed the relatedness of 93.8 ± 4.5, 96.2 ± 4.2 and 82.3 ± 4.8 %, respectively. Based on the polyphasic analysis, a novel species in a new genus, Negadavirga Shengliensis gen. nov., sp. nov., is proposed with SLG210-21(T) (=LMG 27737(T) = CGMCC1.12768(T)) [corrected] as the type strain.

Glycocaulis alkaliphilus sp. nov., a dimorphic prosthecate bacterium isolated from crude oil.

A bacterial strain designated 6B-8(T) was isolated from crude oil from Daqing oilfield, China. Cells of strain 6B-8(T) were Gram-negative, aerobic, dimorphic and reproduced by means of binary fission. Strain 6B-8(T) could grow at 20-37 °C, pH 8-10 and 1-5 % (w/v) NaCl. Its genomic DNA G+C content was 62.0 mol%. The predominant cellular fatty acids were C18 : 1ω7c, C17 : 0, C18 : 0 and 11-methyl C18 : 1ω7c and the main hydroxy fatty acids were C12 : 0 3-OH and C12 : 1 3-OH when grown on marine agar 2216. The major quinone was Q-10 and the major polar lipids were three unidentified glycolipids. Phylogenetic analysis revealed that strain 6B-8(T) was a member of the family Hyphomonadaceae, sharing 99.6 and 99.4 % 16S rRNA gene sequence similarity with Glycocaulis abyssi LMG 27140(T) and Glycocaulis albus SLG210-30A1(T), respectively, and less than 94.4 % similarity with the type strains of other members of the family Hyphomonadaceae. However, the DNA-DNA relatedness between strain 6B-8(T) and related strains G. abyssi LMG 27140(T) and G. albus SLG210-30A1(T) was 36±5 and 42±5 %, respectively. In addition, several phenotypic and genotypic features allowed differentiation of strain 6B-8(T) from G. abyssi LMG 27140(T) and G. albus SLG210-30A1(T). Therefore, strain 6B-8(T) represents a novel species of genus Glycocaulis, for which the name Glycocaulis alkaliphilus sp. nov. is proposed. The type strain is 6B-8(T) ( = CGMCC 1.12428(T) = LMG 27410(T)).

Halodurantibacterium flavum gen. nov., sp. nov., a non-phototrophic bacterium isolated from an oil production mixture.

Three Gram-negative bacterial strains, DQW12E6-69-1(T), DQW12E61-22-1, and DQW12E6-22-1-1, were isolated from an oil production mixture from Daqing Oilfield, northeastern China. The phylogenetic analysis based on the 16S rRNA gene sequences revealed that the three strains formed a stable cluster different from the known genus in Rhodobacteraceae of Alphaproteobacteria. In addition, they were most closely related to species in genera Pararhodobacter, Rhodobacter ,and Rhodobaca with the 16S rRNA gene sequence similarities being 95.1-95.9 %. Cells of the three strains were aerobic; they do not require salt to grow but are resistant to high salinity. They could conduct chemoorganoheterotrophic growth on various carbon sources, with non-phototrophic growth observed. The genomic DNA G+C contents of the strains DQW12E6-69-1(T), DQW12E6-22-1-1, and DQW12E61-22-1 were 63.8, 63.7, and 63.6 mol%, respectively. The predominant respiratory ubiquinone of DQW12E6-69-1(T) was Q-10, and the major fatty acids were C18:1 ω7c, C(18:0), and C(10:0) 3-OH. Photosynthetic pigments and photosynthetic reaction center gene pufM were not detected. The polar lipids were phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, unidentified glycolipid, and unidentified phospholipid. On the basis of phenotypic, genotypic, and chemotaxonomic characteristics, strains DQW12E6-69-1(T), DQW12E61-22-1, and DQW12E6-22-1-1 represent a novel genus and a novel species of the family Rhodobacteraceae. The name Halodurantibacterium flavum gen. nov., sp. nov. is proposed with strain DQW12E6-69-1(T) (=LMG 27742(T) = CGMCC 1.12756(T)) as the type strain.

Glycocaulis albus sp. nov., a moderately halophilic dimorphic prosthecate bacterium isolated from petroleum-contaminated saline soil.

Two novel bacterial strains, SLG210-30A1(T) and SLG210-19A2, which shared 99.9 % 16S rRNA gene sequence similarity with each other, were isolated from petroleum-contaminated saline soil in Shengli Oilfield, eastern China. Cells were Gram-stain-negative, motile, aerobic, mesophilic and moderately halophilic. They could grow chemoheterotrophically with oxygen as an electron acceptor. Morphologically, cells were typical Caulobacteria-type dimorphic prosthecate bacteria. The genomic DNA G+C contents of strains SLG210-30A1(T) and SLG210-19A2 were 61.8 mol% and 61.6 mol% respectively. Strain SLG210-30A1(T) had Q10 as the predominant respiratory ubiquinone, and C16 : 0 (28.4 %), C17 : 0 (11.6 %), C18 : 0 (22.1 %) and C18 : 1ω7c (14.0 %) as the major cellular fatty acids. The polar lipids of the two isolates were some glycolipids, a lipid, a phospholipid, an aminoglycolipid and an aminophospholipid (all unidentified). The 16S rRNA gene sequences of strains SLG210-30A1(T) and SLG210-19A2 showed the highest similarities with Glycocaulis abyssi MCS 33(T) (99.8-99.9 %), but low sequence similarities (<94.7 %) with type strains of other members of the family Hyphomonadaceae. However, the DNA-DNA relatedness of G. abyssi MCS 33(T) to strains SLG210-30A1(T) and SLG210-19A2 was 37.4±4.4 % and 36.1±1.1 %, respectively. Based on different physiological, biochemical, and phylogenetic characteristics, strains SLG210-30A1(T) and SLG210-19A2 represent a novel species of the genus Glycocaulis. The name Glycocaulis albus is therefore proposed with strain SLG210-30A1(T) ( = LMG 27741(T) = CGMCC 1.12766(T)) as the type strain. An emended description of the genus Glycocaulis is also provided.

Diverse bacteria isolated from microtherm oil-production water.

In total, 435 pure bacterial strains were isolated from microtherm oil-production water from the Karamay Oilfield, Xinjiang, China, by using four media: oil-production water medium (Cai medium), oil-production water supplemented with mineral salt medium (CW medium), oil-production water supplemented with yeast extract medium (CY medium), and blood agar medium (X medium). The bacterial isolates were affiliated with 61 phylogenetic groups that belong to 32 genera in the phyla Actinobacteria, Firmicutes, and Proteobacteria. Except for the Rhizobium, Dietzia, and Pseudomonas strains that were isolated using all the four media, using different media led to the isolation of bacteria with different functions. Similarly, nonheme diiron alkane monooxygenase genes (alkB/alkM) also clustered according to the isolation medium. Among the bacterial strains, more than 24 % of the isolates could use n-hexadecane as the sole carbon source for growth. For the first time, the alkane-degrading ability and alkB/alkM were detected in Rhizobium, Rhodobacter, Trichococcus, Micrococcus, Enterococcus, and Bavariicoccus strains, and the alkM gene was detected in Firmicutes strains.

Impacts of different nanoparticles on functional bacterial community in activated sludge.

Rapidly developing industry raises concerns about the environmental impacts of nanoparticles, but the effects of inorganic nanoparticles on functional bacterial community in wastewater treatment remain unclear. The discriminated effects of silver nanoparticles (Ag-NP) and zinc oxide nanoparticles (ZnO-NP) in a simulated sequencing batch reactor (SBR) system were therefore evaluated by the RNA-based terminal restricted fragment length polymorphism (T-RFLP), 16S rcDNA gene clone library and real-time reverse transcription-PCR (RT-PCR) analyses. Although the COD and NH4-N removal efficiencies were not or slightly reduced by the addition of ZnO-NP and Ag-NP, the functional bacterial community changed remarkably. The denitrification related species were inhibited by high dosage of ZnO-NP and Ag-NP, including Diaphorobacter species, Thauera species and those in the Sphaerotilus-Leptothrix group. However, the bacteria related to sludge bulking, heavy metal resistant and biosorption were increased, especially by ZnO-NPs treatment, including those closely related to Haliscomenobacter hydrossis, Zoogloea ramigera and Methyloversatilis universalis. In addition, Ag-NP and ZnO-NP treatments influenced the functional bacterial community differently. Increasing of bulking related bacteria may help to compensate the COD removal efficiency and to maintain functional redundancy, but could lead to operation failure of activated sludge system when expose to ZnO-NPs.

The genome of the moderate halophile Amycolicicoccus subflavus DQS3-9A1(T) reveals four alkane hydroxylation systems and provides some clues on the genetic basis for its adaptation to a petroleum environment.

The moderate halophile Amycolicicoccus subflavus DQS3-9A1(T) is the type strain of a novel species in the recently described novel genus Amycolicicoccus, which was isolated from oil mud precipitated from oil produced water. The complete genome of A. subflavus DQS3-9A1(T) has been sequenced and is characteristic of harboring the genes for adaption to the harsh petroleum environment with salinity, high osmotic pressure, and poor nutrient levels. Firstly, it characteristically contains four types of alkane hydroxylases, including the integral-membrane non-heme iron monooxygenase (AlkB) and cytochrome P450 CYP153, a long-chain alkane monooxygenase (LadA) and propane monooxygenase. It also accommodates complete pathways for the response to osmotic pressure. Physiological tests proved that the strain could grow on n-alkanes ranging from C10 to C36 and propane as the sole carbon sources, with the differential induction of four kinds of alkane hydroxylase coding genes. In addition, the strain could grow in 1-12% NaCl with the putative genes responsible for osmotic stresses induced as expected. These results reveal the effective adaptation of the strain DQS3-9A1(T) to harsh oil environment and provide a genome platform to investigate the global regulation of different alkane metabolisms in bacteria that are crucially important for petroleum degradation. To our knowledge, this is the first report to describe the co-existence of such four types of alkane hydroxylases in a bacterial strain.

Bacteria in crude oil survived autoclaving and stimulated differentially by exogenous bacteria.

Autoclaving of crude oil is often used to evaluate the hydrocarbon-degrading abilities of bacteria. This may be potentially useful for bioaugmentation and microbial enhanced oil recovery (MEOR). However, it is not entirely clear if "endogenous" bacteria (e.g., spores) in/on crude oil survive the autoclaving process, or influence subsequent evaluation of the hydrocarbon-degradation abilities of the "exogenous" bacterial strains. To test this, we inoculated autoclaved crude oil medium with six exogenous bacterial strains (three Dietzia strains, two Acinetobacter strains, and one Pseudomonas strain). The survival of the spore-forming Bacillus and Paenibacillus and the non-spore-forming mesophilic Pseudomonas, Dietzia, Alcaligenes, and Microbacterium was detected using a 16S rRNA gene clone library and terminal restriction fragment length polymorphism (T-RFLP) analysis. However, neither bacteria nor bacterial activity was detected in three controls consisting of non-inoculated autoclaved crude oil medium. These results suggest that detection of endogenous bacteria was stimulated by the six inoculated strains. In addition, inoculation with Acinetobacter spp. stimulated detection of Bacillus, while inoculation with Dietzia spp. and Pseudomonas sp. stimulated the detection of more Pseudomonas. In contrast, similar exogenous bacteria stimulated similar endogenous bacteria at the genus level. Based on these results, special emphasis should be applied to evaluate the influence of bacteria capable of surviving autoclaving on the hydrocarbon-degrading abilities of exogenous bacteria, in particular, with regard to bioaugmentation and MEOR. Bioaugmentation and MEOR technologies could then be developed to more accurately direct the growth of specific endogenous bacteria that may then improve the efficiency of treatment or recovery of crude oil.

Corn stover saccharification with concentrated sulfuric acid: effects of saccharification conditions on sugar recovery and by-product generation.

Although concentrated sulfuric acid saccharification is not a novel method for breaking down lignocellulosic biomass, the process by which saccharification affects biomass decomposition, sugar recovery, and by-product generation is not well studied. The present study employed Taguchi experimental design to study the effects of seven parameters on corn stover concentrated sulfuric acid saccharification. The concentration of sulfuric acid and the temperature of solubilization significantly affect corn stover decomposition. They also have significant effects on glucose and xylose recoveries. Low generation of furfural and 5-hydroxymethyl-2-furfural (5HMF) was noted and organic acids were the main by-products detected in the hydrolysate. Temperature also significantly affected the generation of levulinic acid and formic acid; however, acetic acid generation was not significantly influenced by all seven parameters. The ratio of acid to feedstock significantly affected glucose recovery, but not total sugar recovery. The corn stover hydrolysate was well fermented by both glucose- and xylose-fermenting yeast strains.

Microbial communities in long-term, water-flooded petroleum reservoirs with different in situ temperatures in the Huabei Oilfield, China.

The distribution of microbial communities in the Menggulin (MGL) and Ba19 blocks in the Huabei Oilfield, China, were studied based on 16S rRNA gene analysis. The dominant microbes showed obvious block-specific characteristics, and the two blocks had substantially different bacterial and archaeal communities. In the moderate-temperature MGL block, the bacteria were mainly Epsilonproteobacteria and Alphaproteobacteria, and the archaea were methanogens belonging to Methanolinea, Methanothermobacter, Methanosaeta, and Methanocella. However, in the high-temperature Ba19 block, the predominant bacteria were Gammaproteobacteria, and the predominant archaea were Methanothermobacter and Methanosaeta. In spite of shared taxa in the blocks, differences among wells in the same block were obvious, especially for bacterial communities in the MGL block. Compared to the bacterial communities, the archaeal communities were much more conserved within blocks and were not affected by the variation in the bacterial communities.

The genome sequence of Polymorphum gilvum SL003B-26A1(T) reveals its genetic basis for crude oil degradation and adaptation to the saline soil.

Polymorphum gilvum SL003B-26A1(T) is the type strain of a novel species in the recently published novel genus Polymorphum isolated from saline soil contaminated with crude oil. It is capable of using crude oil as the sole carbon and energy source and can adapt to saline soil at a temperature of 45°C. The Polymorphum gilvum genome provides a genetic basis for understanding how the strain could degrade crude oil and adapt to a saline environment. Genome analysis revealed the versatility of the strain for emulsifying crude oil, metabolizing aromatic compounds (a characteristic specific to the Polymorphum gilvum genome in comparison with other known genomes of oil-degrading bacteria), as well as possibly metabolizing n-alkanes through the LadA pathway. In addition, COG analysis revealed Polymorphum gilvum SL003B-26A1(T) has significantly higher abundances of the proteins responsible for cell motility, lipid transport and metabolism, and secondary metabolite biosynthesis, transport and catabolism than the average levels found in all other genomes sequenced thus far, but lower abundances of the proteins responsible for carbohydrate transport and metabolism, defense mechanisms, and translation than the average levels. These traits support the adaptability of Polymorphum gilvum to a crude oil-contaminated saline environment. The Polymorphum gilvum genome could serve as a platform for further study of oil-degrading microorganisms for bioremediation and microbial-enhanced oil recovery in harsh saline environments.

Two novel alkane hydroxylase-rubredoxin fusion genes isolated from a Dietzia bacterium and the functions of fused rubredoxin domains in long-chain n-alkane degradation.

Two alkane hydroxylase-rubredoxin fusion gene homologs (alkW1 and alkW2) were cloned from a Dietzia strain, designated DQ12-45-1b, which can grow on crude oil and n-alkanes ranging in length from 6 to 40 carbon atoms as sole carbon sources. Both AlkW1 and AlkW2 have an integral-membrane alkane monooxygenase (AlkB) conserved domain and a rubredoxin (Rd) conserved domain which are fused together. Phylogenetic analysis showed that these two AlkB-fused Rd domains formed a novel third cluster with all the Rds from the alkane hydroxylase-rubredoxin fusion gene clusters in Gram-positive bacteria and that this third cluster was distant from the known AlkG1- and AlkG2-type Rds. Expression of the alkW1 gene in DQ12-45-1b was induced when cells were grown on C(8) to C(32) n-alkanes as sole carbon sources, but expression of the alkW2 gene was not detected. Functional heterologous expression in an alkB deletion mutant of Pseudomonas fluorescens KOB2Δ1 suggested the alkW1 could restore the growth of KOB2Δ1 on C(14) and C(16) n-alkanes and induce faster growth on C(18) to C(32) n-alkanes than alkW1ΔRd, the Rd domain deletion mutant gene of alkW1, which also caused faster growth than KOB2Δ1 itself. In addition, the artificial fusion of AlkB from the Gram-negative P. fluorescens CHA0 and the Rds from both Gram-negative P. fluorescens CHA0 and Gram-positive Dietzia sp. DQ12-45-1b significantly increased the degradation of C(32) alkane compared to that seen with AlkB itself. In conclusion, the alkW1 gene cloned from Dietzia species encoded an alkane hydroxylase which increased growth on and degradation of n-alkanes up to C(32) in length, with its fused rubredoxin domain being necessary to maintain the functions. In addition, the fusion of alkane hydroxylase and rubredoxin genes from both Gram-positive and -negative bacteria can increase the degradation of long-chain n-alkanes (such as C(32)) in the Gram-negative bacterium.

Degradation of petroleum hydrocarbons (C6-C40) and crude oil by a novel Dietzia strain.

A novel bacterial strain, DQ12-45-1b, was isolated from the production water of a deep subterranean oil-reservoir. Morphological, physiological and phylogenetic analyses indicated that the strain belonged to the genus Dietzia with both alkB (coding for alkane monooxygenase) and CYP153 (coding for P450 alkane hydroxylase of the cytochrome CYP153 family) genes and their induction detected. It was capable of utilizing a wide range of n-alkanes (C6-C40), aromatic compounds and crude oil as the sole carbon sources for growth. In addition, it preferentially degraded short-chain hydrocarbons (≤C25) in the early cultivation phase and accumulated hydrocarbons with chain-lengths from C23 to C27 during later cultivation stage with crude oil as the sole carbon source. This is the first study to report the different behaviors of a bacterial species toward crude oil degradation as well as a species of Dietzia degrading a wide range of hydrocarbons.

Complete genome sequence of Polymorphum gilvum SL003B-26A1T, a crude oil-degrading bacterium from oil-polluted saline soil.

Polymorphum gilvum SL003B-26A1(T) is a type strain of a newly published novel species in the novel genus Polymorphum. It was isolated from a crude oil-polluted saline soil in Shengli Oilfield, China, and was able to use the crude oil as the sole carbon source. Here we report the complete genome of SL003B-26A1(T) and the genes likely to be involved in oil degradation and ecological adaption.

Salinarimonas ramus sp. nov. and Tessaracoccus oleiagri sp. nov., isolated from a crude oil-contaminated saline soil.

Four bacterial strains, SL014B-41A4(T), SL014B-20A1(T), SL014B-76A1 and SL014B-79A, isolated from a crude oil-contaminated saline soil of Shengli Oilfield, China, were investigated using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain SL014B-41A4(T) belonged to the genus Salinarimonas in the order Rhizobiales, with the highest sequence similarity with Salinarimonas rosea YIM YD3(T) (98.3 %). The DNA-DNA relatedness of strain SL014B-41A4(T) to S. rosea YIM YD3(T) was 27.03 ± 3.0 %. Strain SL014B-41A4(T) was Gram-negative staining, facultatively anaerobic and produced deep red pigment in artificial seawater medium. Cells of strain SL014B-41A4(T) were rod-shaped (0.6-4.0 × 1.25-25 µm), motile with a single polar flagellum and often formed branches. The strain contained Q-10 as the predominant respiratory ubiquinone and C(18 : 1)ω7c (57.5 %), C(16 : 0) (16.4 %) and 10-methyl C(19 : 0) (9.1 %) as the major fatty acids. Strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A were actinobacteria and belonged to the genus Tessaracoccus in the family Propionibacteriaceae of the order Actinomycetales with the highest 16S rRNA gene sequence similarities with Tessaracoccus flavescens SST-39(T) (96.4 %), Tessaracoccus lubricantis KISS-17Se(T) (96.2 %) and Tessaracoccus bendigoensis Ben 106(T) (94.7 %). Strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A were Gram-positive staining, facultatively anaerobic, non-endospore-forming, non-motile, acid-fast and oval to rod-shaped (0.48 × 0.5-1.0 µm). These three novel strains had ll-diaminopimelic acid (DAP) as the diagnostic diamino acid in the cell-wall peptidoglycan, MK-9(H(4)) as the only menaquinone and anteiso-C(15 : 0) (67.11-76.14 %) as the major cellular fatty acid. The G+C contents of the genomic DNA of strain SL014B-41A4(T) and strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A were 67.68 mol% and 65.65-67.17 mol%, respectively. Based on phenotypic and genotypic characteristics, strain SL014B-41A4(T) represents a novel species of the genus Salinarimonas, for which the name Salinarimonas ramus is proposed, with strain SL014B-41A4(T) ( = DSM 22962(T) = CGMCC 1.9161(T)) as the type strain. Strains SL014B-20A1(T), SL014B-76A1 and SL014B-79A represent a novel species of the genus Tessaracoccus, for which the name Tessaracoccus oleiagri is proposed, with strain SL014B-20A1(T) ( = DSM 22955(T) = CGMCC 1.9159(T)) as the type strain.