Facultative Anaerobic Strain Research Articles

Halosquirtibacter laminarini gen. nov., sp. nov. and Halosquirtibacter xylanolyticus sp. nov., marine anaerobic laminarin and xylan degraders in the phylum Bacteroidota

The bacterial group of the phylum Bacteroidota greatly contributes to the global carbon cycle in marine ecosystems through its specialized ability to degrade marine polysaccharides. In this study, it is proposed that two novel facultative anaerobic strains, DS1-an-13321T and DS1-an-2312T, which were isolated from a sea squirt, represent a novel genus, Halosquirtibacter, with two novel species in the family Prolixibacteraceae. The 16S rRNA sequence similarities of these two strains were 91.26% and 91.37%, respectively, against Puteibacter caeruleilacunae JC036T, which is the closest recognized neighbor. The complete genomes of strains DS1-an-13321T and DS1-an-2312T each consisted of a single circular chromosome with a size of 4.47 and 5.19 Mb, respectively. The average amino acid identity and the percentage of conserved proteins against the type species of the genera in the family Prolixibacteraceae ranged from 48.33 to 52.35% and 28.34–37.37%, respectively, which are lower than the threshold for genus demarcation. Strains DS1-an-13321T and DS1-an-2312T could grow on galactose, glucose, maltose, lactose, sucrose, laminarin, and starch, and only DS1-an-2312T could grow on xylose and xylan under fermentation conditions. These strains produced acetic acid and propionic acid as the major fermentation products. Genome mining of the genomes of the two strains revealed 27 and 34 polysaccharide utilization loci, which included 155 and 249 carbohydrate-active enzymes (CAZymes), covering 57 and 65 CAZymes families, respectively. The laminarin-degrading enzymes in both strains were cell-associated, and showed exo-hydrolytic activity releasing glucose as a major product. The xylan-degrading enzymes of strain DS1-an-2312T was also cell-associated, and had endo-hydrolytic activities, releasing xylotriose and xylotetraose as major products. The evidence from phenotypic, biochemical, chemotaxonomic, and genomic characteristics supported the proposal of a novel genus with two novel species in the family Prolixibacteraceae, for which the names Halosquirtibacter laminarini gen. nov., sp. nov. and Halosquirtibacter xylanolyticus sp. nov. are proposed. The type strain of Halosquirtibacter laminarini is DS1-an-13321T (= KCTC 25031T = DSM 115329T) and the type strain of Halosquirtibacter xylanolyticus is DS1-an-2312T (= KCTC 25032T = DSM 115328T).

Isolation and Electrochemical Analysis of a Facultative Anaerobic Electrogenic Strain Klebsiella sp. SQ-1.

Electricigens decompose organic matter and convert stored chemical energy into electrical energy through extracellular electron transfer. They are significant biocatalysts for microbial fuel cells with practical applications in green energy generation, effluent treatment, and bioremediation. A facultative anaerobic electrogenic strain SQ-1 is isolated from sludge in a biotechnology factory. The strain SQ-1 is a close relative of Klebsiella variicola. Multilayered biofilms form on the surface of a carbon electrode after the isolated bacteria are inoculated into a microbial fuel cell device. This strain produces high current densities of 625 μA cm-2 by using acetate as the carbon source in a three-electrode configuration. The electricity generation performance is also analyzed in a dual-chamber microbial fuel cell. It reaches a maximum power density of 560 mW m-2 when the corresponding output voltage is 0.59 V. The facultative strain SQ-1 utilizes hydrous ferric oxide as an electron acceptor to perform extracellular electricigenic respiration in anaerobic conditions. Since facultative strains possess better properties than anaerobic strains, Klebsiella sp. SQ-1 may be a promising exoelectrogenic strain for applications in microbial electrochemistry.

Acute Ammonia Causes Pathogenic Dysbiosis of Shrimp Gut Biofilms.

Acute ammonia exposure has detrimental effects on shrimp, but the underlying mechanisms remain to be fully explored. In the present study, we investigated the impact of acute ammonia exposure on the gut microbiota of the white shrimp Litopenaeus vannamei and its association with shrimp mortality. Exposure to a lethal concentration of ammonia for 48 h resulted in increased mortality in L. vannamei, with severe damage to the hepatopancreas. Ammonia exposure led to a significant decrease in gut microbial diversity, along with the loss of beneficial bacterial taxa and the proliferation of pathogenic Vibrio strains. A phenotypic analysis revealed a transition from the dominance of aerobic to facultative anaerobic strains due to ammonia exposure. A functional analysis revealed that ammonia exposure led to an enrichment of genes related to biofilm formation, host colonization, and virulence pathogenicity. A species-level analysis and experiments suggest the key role of a Vibrio harveyi strain in causing shrimp disease and specificity under distinct environments. These findings provide new information on the mechanism of shrimp disease under environmental changes.

Complete genome sequence of Afipia carboxidovorans strain SH125, a non-denitrifying nitrous oxide-reducing bacterium isolated from anammox biomass.

Here, we report a genome sequence of Afipia carboxidovorans strain SH125 isolated from an anammox reactor. This facultative anaerobic strain possesses the clade I-type nitrous oxide (N2O) reductase gene, devoid of nitrite- and nitric oxide reductase genes. Deciphering the genome will help explore N2O reducers instrumental in N2O mitigation.

Mesorhizobium liriopis sp. nov., isolated from the fermented fruit of Liriope platyphylla a medicinal plant.

A facultative anaerobic and Gram-negative strain, designated RP14T, was isolated from the fruit of Liriope platyphylla fermented for 60 days at 25°C. Strain RP14T showed 98.0 % 16S rRNA similarity to Mesorhizobium huakuii IFO 15243T, but in the phylogenetic tree, Mesorhizobium terrae NIBRBAC000500504T was its closest neighbour. The average nucleotide identity and digital DNA-DNA hybridization values between strain RP14T and 15 genomes of type strains of Mesorhizobium, were 73.8-74.4% and 16.4-20.2 %, respectively, which were lower than the recommended thresholds for species delineation. The strain grew at 25-32°C (optimum, 28°C), at pH 7.0-12.0 (optimum, pH 9.0) and with 0-2% NaCl (optimum, 0 %; w/v). Cells of strain RP14T were catalase-positive, oxidase-negative, rod-shaped and formed yellow-coloured colonies. The major polar lipids were phosphatidylethanolamine, diphosphatidylglycerol and phosphatidylglycerol. The major fatty acid were C16 : 0, C19 : 0 cyclo ω8c and summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c). The DNA G+C content was 62.8 mol%. Based on polyphasic evidence, we propose Mesorhizobium liriopis sp. nov as a novel species within the genus Mesorhizobium. The type strain is RP14T (=KACC 22720T=TBRC 16341T).

The Isolation of Anaerobic and Facultative Anaerobic Sulfate-Reducing Bacteria (SRB) and a Comparison of Related Enzymes in Their Sulfate Reduction Pathways.

Sulfate-reducing bacteria (SRB) are an important group of microorganisms that cause microbial corrosion. In this study, culturable SRB were isolated and identified from the inner rust layer of three kinds of steel and from sediments, and a comparison of amino acid sequences encoding related enzymes in the sulfate reduction pathway between anaerobic and facultative anaerobic SRB strains was carried out. The main results are as follows. (1) Seventy-seven strains were isolated, belonging to five genera and seven species, with the majority being Desulfovibrio marinisediminis. For the first time, Holodesulfovibrio spirochaetisodalis and Acinetobacter bereziniae were separated from the inner rust layer of metal, and sulfate reduction by A. bereziniae, Virgibacillus dokdonensis, and Virgibacillus chiguensis, etc., was also demonstrated for the first time. (2) Three strains of strictly anaerobic bacteria and four strains of facultative anaerobic bacteria were screened from seven bacterial strains. (3) Most of the anaerobic SRB only contained enzymes for the dissimilatory sulfate reduction pathway, while those of facultative anaerobic bacteria capable of producing hydrogen sulfide included two possible ways: containing the related enzymes from the dissimilatory pathway only, or containing enzymes from both dissimilatory and assimilation pathways. This study newly discovered that some bacterial genera exhibit sulfate reduction ability and found that there are differences in the distribution of enzymes related to the sulfate reduction pathway between anaerobic and facultative anaerobic SRB type trains, providing a basis for the development and utilization of sulfate-reducing bacterial resources and furthering our understanding of the metabolic mechanisms of SRB.

Arthrobacter caoxuetaonis sp. nov., Arthrobacter zhangbolii sp. nov. and Arthrobacter gengyunqii sp. nov., isolated from Marmota himalayana faeces from Qinghai-Tibet Plateau.

Six aerobic or facultative anaerobic, motile, Gram-stain-positive, catalase-positive and oxidase-negative strains (zg-Y453T, zg-Y324, zg-Y462T, zg-Y411, zg-Y809T and zg-Y786) were isolated from different faecal samples of Marmota himalayana from the Qinghai-Tibet Plateau. Pale yellow, round, raised and moist colonies appeared 48 h after incubation at 28 °C on brain-heart infusion plates supplemented with 5 % defibrinated sheep blood. According to the 16S rRNA gene sequence alignment, two strain pairs (zg-Y453T/zg-Y324 and zg-Y462T/zg-Y411) shared the highest similarities to Arthrobacter luteolus (99.5 and 99.2 %), and the other one (zg-Y809T/zg-Y786) to Arthrobacter citreus (99.5 %). Results of phylogenetic analysis based on the 16S rRNA gene and genome sequences showed that these six strains represented three separate species within the genus Arthrobacter. The average nucleotide identity and digital DNA-DNA hybridization values between the three novel type strains (zg-Y453T/zg-Y462T/zg-Y809T) and other known species in this genus were all below respective thresholds (70.2-81.5/19.6-24.2 %, 70.6-81.8/19.8-25.0 %, and 70.4-88.2/19.9-35.3 %). Although phylogenetically related, there were obvious chemotaxonomic and phenotypic differences: strain pair zg-Y462T/zg-Y411 had anteiso-C15 : 0 as the only major fatty acid; the three novel species had different dominant quinones, MK-8(H2) in strains zg-Y462T/zg-Y809T (74.8/81.1 %) and MK-8(H2)/MK-9(H2) (43.1/53.0 %) in zg-Y453T; similarly, the ability to reduce nitrate in strains zg-Y453T and zg-Y462T could differentiate them from zg-Y809T. All strains had diphosphatidylglycerol, phosphatidylglycerol and phosphatidylinositol, but differed slightly in the types of unidentified glycolipids, phospholipids and lipids. Based on the results of these polyphasic taxonomic analyses, three novel species within the genus Arthrobacter are proposed, namely Arthrobacter caoxuetaonis sp. nov. (type strain, zg-Y453T=GDMCC 1.2809T=JCM 35173T), Arthrobacter zhangbolii sp. nov. (type strain, zg-Y462T=GDMCC 1.2880T=JCM 35170T) and Arthrobacter gengyunqii sp. nov. (type strain, zg-Y809T=GDMCC 1.2808T=JCM 35168T).

Strengthening in microbiota dynamics and C, N, S transformation induced by novel synthesized pyrite/PHBV composites for advanced nitrogen and phosphate removal: Overlooked sulfate reduction process

Fine-grained pyrites are difficult to be denitrified under natural environment due to chemical oxidation with O2. In this study, the pyrite/PHBV composites were synthesized through high-temperature melting and realized nitrogen and phosphate removal under natural aerobic conditions. Results showed that pyrite/PHBV-40 composites had the highest denitrification rate of 0.61 mg NO3−–N /(L·h) with low SO42− production, and its removal efficiency of nitrogen and phosphorus was 98% and 41%, respectively. Microbial community structure analysis revealed that the enrich sulfate-reducing bacteria (SRB) on the pyrite/PHBV-40 composites demonstrated that the sulfate reduction driven by SRB enhanced denitrification process, and thereby the S cycle could underpin the potential self-sustainability of pyrite/PHBV-40 composites. Co-occurrence network analysis showed that Fe oxidizers/reducers (e.g., Ferruginibacter/Geobacter) and SRB (e.g., Desulfovibrio) were the keystone species in microbial community. Bugbase analysis showed that formed biofilms mainly consisted of aerobic and facultative anaerobic strains, which was corresponding to structure of biofilm including aerobic and anoxic layer. Partial mantel test revealed the total Fe and nutrients (e.g., N and P) are the drivers in OTU and phenotype composition, respectively. Metabolic pathway analysis suggested that pyrite/PHBV composites may not only accelerate glycolysis with rapid hydrolysis of PHBV, but also enhance the TCA cycle with high production of ATP and NADH. The final product of nitrate reduction is N2O or NO, and the cysJ gene play an important role in sulfate reduction in pyrite/PHBV systems. Overall, the novel synthesized pyrite/PHBV composites are an ideal functional material with high denitrification rate, no secondary pollution and long service life. Our study highlights pyrite/PHBV-induced strength in microbiota dynamics and C, N, S transformation, therein, the sulfate reduction process cannot be overlooked.

Levilactobacillus yiduensis sp. nov., Isolated from Zha-chili in Yidu County, Hubei Province, China

The zha-chili isolate HBUAS62285T is a facultative anaerobic strain. This bacterium was gram-positive, but it could not generate catalase, was not motile, did not form spores, had no flagella, and produced gamma-aminobutyric acid (GABA). Comparing of HBUAS62285T with its related type strains Levilactobacillus suantsaiihabitans BCRC 81129T, Levilactobacillus angrenensis M1530-1T, Levilactobacillus cerevisiae DSM 100836T, Levilactobacillus wangkuiensis 6-5(1)T, Levilactobacillus lanxiensis 13B17T, and Levilactobacillus mulengensis 112-3T showed that the similarity of 16S rRNA gene sequence was less than 99.13%. Strain HBUAS62285T has a G+C content of 50.57mol%, an ANI value of less than 86.61%, an AAI value of less than 92.9%, and a dDDH value of less than 32.9% when compared to the aforementioned closely related strains. In the end, the most major fatty acids in cells were determined to be C16:0, C18:1 ω9c, C19:1 cyclo ω9,10c, and summed feature 10. Overall, the results of the phenotypic, genomic, chemotaxonomic, and phylogenetic studies indicate that strains HBUAS62285T and CD0817 constitute a new species within the genus Levilactobacillus, and the name Levilactobacillus yiduensis sp. nov. is proposed. The type strain is HBUAS62285T (= JCM 35804T = GDMCC 1.3507T).

In vitro efficacy of antibiotic loaded calcium sulfate beads (Stimulan Rapid Cure) against polymicrobial communities and individual bacterial strains derived from diabetic foot infections.

Introduction. Diabetic foot infection (DFI) is the main reason for diabetes-related hospitalisation and is a major cause of diabetes-related amputation. DFIs are often complicated by ischaemia in the affected limb, the presence of polymicrobial biofilms and increasingly the occurrence of antibiotic resistant bacteria.Hypothesis/Gap statement. Antibiotic loaded beads could inhibit the growth of polymicrobial DFI communities with differing compositions in vitro.Aim. This study investigates the in vitro efficacy of antibiotic loaded calcium sulfate beads (Stimulan Rapid Cure, Biocomposites Ltd., UK) against polymicrobial DFI communities and individual bacterial strains derived from DFIs.Methodology. Debrided tissue obtained from the base of infected diabetic foot ulcers was homogenised and spread over the surface of Columbia blood agar (CBA) and fastidious anaerobe agar (FAA) plates. Calcium sulfate beads containing a combination of vancomycin and gentamicin were then placed on the surface of the agar and following incubation, zones of inhibition (ZOI) were measured. For individual bacterial strains isolated from the infected tissue, calcium sulfate beads containing vancomycin, gentamicin, flucloxacillin or rifampicin and beads containing a combination of vancomycin and gentamicin or flucloxacillin and rifampicin were tested for their ability to inhibit growth.Results. Calcium sulfate beads loaded with a combination of vancomycin and gentamicin were able to inhibit bacterial growth from all polymicrobial tissue homogenates tested, with ZOI diameters ranging from 15 to 40 mm. In the case of individual bacterial strains, beads containing combinations of vancomycin and gentamicin or flucloxacillin and rifampicin were able to produce ZOI with Gram-positive facultatitive anaerobic strains such as Staphylococcus aureus and Enterococcus faecalis, Gram-negative facultative anaerobic strains such as Pseudomonas aeruginosa and obligate anaerobic strains such as Finegoldia magna even where acquired resistance to one of the antibiotics in the combination was evidenced.Conclusion. The local use of calcium sulfate beads containing a combination of two antibiotics demonstrated high efficacy against polymicrobial DFI communities and individual DFI bacterial strains in in vitro zone of inhibition tests. These results show promise for clinical application, but further research and clinical studies are required.

Psychroserpens luteolus sp. nov., isolated from Gelidium, reclassification of Ichthyenterobacterium magnum as Psychroserpens magnus comb. nov., Flavihalobacter algicola as Psychroserpens algicola comb. nov., Arcticiflavibacter luteus as Psychroserpens luteus comb. nov.

A Gram-stain-negative, motile by gliding, catalase positive, facultative anaerobic strain, designated strain XSD401T, was isolated from an unidentified Gelidium species of Xiaoshi Island, Shandong Province, China. The 16S rRNA gene sequence comparisons indicated strain XSD401T had a sequence similarity of 96.9% with Psychroserpens damuponensis KCTC 23539T and 96.3% with Psychroserpens burtonensis DSM 12212T. The G + C content of the genomic DNA was 33.9%. The ANI values between strain XSD401T and P. damuponensis KCTC 23539T, P. burtonensis DSM 12212T, were 76.9% and 76.9%, respectively. The dDDH values between strain XSD401T and P. damuponensis KCTC 23539T, P. burtonensis DSM 12212T, were 20.4% and 20.3%, respectively. The AAI values and POCP values of these 8 species were all over 72% and 50%. Combined with the results of comparative genomic analysis, Ichthyenterobacterium magnum, Flavihalobacter algicola and Arcticiflavibacter luteus were reclassified into Psychroserpens. Furthermore, the differences in morphology, physiology and genotype from the previously described taxa support the classification of strain XSD401T as a representative of the genus Psychroserpens, for which the name Psychroserpens luteolus sp. nov. is proposed. The type strain is XSD401T (= MCCC 1H00396T = KCTC 72684T = JCM 33931T).

Fundicoccus fermenti sp. nov., an indigo-reducing facultative anaerobic alkaliphile isolated from indigo fermentation liquor used for dyeing.

Two facultative anaerobic and facultative alkaliphilic indigo-reducing strains, designated F-1T and F-2, were isolated from indigo fermentation liquor produced from couched woad fermentation-based Indian indigo fermentation fluid. The 16S rRNA gene phylogeny showed that Fundicoccus ignavus WS4937T (99.5%) was the closest neighbour of F-1T. The isolated bacterial cells were Gram-stain-positive and facultative anaerobic coccoids. Strain F-1T grew at between 5 and 37 °C with optimum growth between 28‒32 °C. The isolate grew in a pH range of 7.0‒10.5, with optimum growth between pH 9.0‒10.5. The DNA G+C content was 37.6 mol% (HPLC). The whole-cell fatty acid profile mainly consisted (>10 %) of C16 : 0, C16 : 1 ω9c, C18 : 0 and C18 : 1 ω9c. The digital DNA-DNA hybridization value between strain F-1T and F. ignavus WS4937T was 52.9 %. Based on their physiological and biochemical characteristics, and phylogenetic and genomic data, the isolates can be discriminated from F. ignavus WS4937T. The name Fundicoccus fermenti sp. nov. is proposed. The type strain of this species is F-1T (JCM 34140T=NCIMB 15255T).

Commensal Bacteria in the Cystic Fibrosis Airway Microbiome Reduce P. aeruginosa Induced Inflammation.

Chronic Pseudomonas aeruginosa infections play an important role in the progress of lung disease in patients suffering from cystic fibrosis (CF). Recent studies indicate that polymicrobial microbiome profiles in the airway are associated with less inflammation. Thus, the hypothesis was raised that certain commensal bacteria might protect the host from inflammation. We therefore performed a screening study with commensals isolated from CF airway microbiome samples to identify potential beneficial commensals. We isolated more than 80 aerobic or facultative anaerobic commensal strains, including strains from genera Streptococcus, Neisseria, Actinomyces, Corynebacterium, Dermabacter, Micrococcus and Rothia. Through a screening experiment of co-infection in human epithelial cell lines, we identified multiple commensal strains, especially strains belonging to Streptococcus mitis, that reduced P. aeruginosa triggered inflammatory responses. The results were confirmed by co-infection experiments in ex-vivo precision cut lung slices (PCLS) from mice. The underlying mechanisms of the complex host-pathogen-commensal crosstalk were investigated from both the host and the bacterial sides with a focus on S. mitis. Transcriptome changes in the host in response to co-infection and mono-infection were evaluated, and the results indicated that several signalling pathways mediating inflammatory responses were downregulated by co-infection with S. mitis and P. aeruginosa compared to P. aeruginosa mono-infection, such as neutrophil extracellular trap formation. The genomic differences among S. mitis strains with and without protective effects were investigated by whole genome sequencing, revealing genes only present in the S. mitis strains showing protective effects. In summary, through both in vitro and ex vivo studies, we could identify a variety of commensal strains that may reduce host inflammatory responses induced by P. aeruginosa infection. These findings support the hypothesis that CF airway commensals may protect the host from inflammation.

Bioelectrochemical processes of oxidation of dicarboxylic amino acids by strain Micrococcus luteus 1-I in a biofuel cell

A facultative anaerobic strain was isolated and studied from the activated sludge of the treatment facilities of a petrochemical enterprise. Its morphological and cultural, physiological and biochemical, tinctorial, molecular genetic characteristics have been investigated. Based on the data obtained, strain 1-I was assigned to the species Micrococcus luteus. The electrogenic activity of this bacterium in BFC was shown using dicarboxylic amino acids - glutamic and aspartic. The open-circuit voltage indices in the BFC with M. luteus 1-I increased in 6 days to 511.5 mV with the addition of aspartic acid, and 419 ± 38.5 mV with the addition of glutamic acid. In this case, the short-circuit current increased to 3.17 ± 0.12 and 1.6 ± 0.14 mA, respectively. The specific power of BFCs based on M. luteus 1-I was the highest with the addition of aspartic acid (40-50 mW / m2 at a current density of 0.15 to 0.4 A / m2). The indicated indicator in a similar BFC with glutamic acid was 26-32 mW / m2 (at a current density of 0.08 to 0.28 A / m2). The oxidation of these compounds by the studied bacterial strain was also confirmed by the methods of cyclic voltammetry.

Characterization of Vibrio sp. strain AB15 and Pseudomonas fluorescens strain NB14 from the biofloc of shrimp culture ponds capable of high ammonia and nitrite removal efficiency

AbstractThe development of intensive aquaculture industry has aggravated the dangers of ammonia and nitrite in aquatic ecosystems. Probiotics have been widely used to maintain and improve water quality by removal of ammonia and nitrite in aquaculture. In this study, two facultative anaerobic strains AB15 and NB14, capable of efficient ammonia and nitrite removal, were isolated from biofloc, which acts as a natural micro‐flora storeroom in shrimp culture ponds, and were identified as Vibrio sp. and Pseudomonas fluorescens, respectively. The removal efficiency of ammonia and nitrite by AB15 and NB14 was 96.8 and 89.6%, respectively. The optimum conditions of AB15 and NB14 were as follows: temperature (25°C vs. 30°C), salinity (25‰ both), initial pH (7.5 vs. 8.0), C/N ratio (15 vs. 10). The two strains had great performance on inhibiting the common pathogens (Vibrio harveyi, Vibrio splendidus, Vibrio anguillarum) in aquaculture at concentrations of 105–108 CFU/mL. Biosecurity assessment indicated that both AB15 and NB14 were harmless for survival and could be beneficial for the growth and immune enhancement of Litopenaeus vannamei. All results demonstrate that the two isolated strains have high promise for future applications of removing ammonia and nitrite and maintaining biosecurity in shrimp culture ponds.

Sediminibacterium soli sp. nov., isolated from soil.

A Gram-stain-negative, facultative anaerobic strain, designated WSJ-3T, was isolated from soil. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain WSJ-3T belongs to genus Sediminibacterium and exhibits the highest sequence similarities to Sediminibacterium roseum SYL130T (97.0%), Sediminibacterium goheungense DSM 28323T (96.9%), Sediminibacterium aquarii AA5T (96.7%), and Sediminibacterium salmoneum NBRC 103935T (95.2%). The average nucleotide identity values of strain WSJ-3T/S. roseum SYL130T and strain WSJ-3T/S. goheungense DSM 28323T are 72.2% and 70.4%, respectively, and digital DNA-DNA hybridization values for these are 19.2% and 19.1%, respectively. Strain WSJ-3T has a genome size of 3.88Mb, with a DNA G + C content of 50.1mol% and comprises of 3263 predicted genes. A phylogenetic tree constructed using the genomic core protein coding sequences revealed that strain WSJ-3T clusters with S. roseum SYL130T. Strain WSJ-3T has menaquinone-7 as the only respiratory quinone and phosphatidylethanolamine, three unidentified phospholipids, four unidentified aminophospholipids, two unidentified aminolipids, and three unidentified lipids as the polar lipids. The major fatty acids of strain WSJ-3T are iso-C15:0, iso-C17:0 3-OH, and iso-C15:1 G. On the basis of the polyphasic results, the isolate represents a novel species of the genus Sediminibacterium, for which the name Sediminibacterium soli sp. nov. is proposed. The type strain is WSJ-3T (= KCTC 72839T = CCTCC AB 2019408T).

The incidence of anaerobic bacteria in adult patients with chronic sinusitis: A prospective, single-centre microbiological study.

IntroductionChronic sinusitis caused by anaerobes is a particular concern clinically, because many of the complications are associated with infections caused by these organisms. The aim of this study was to evaluate the incidence of anaerobic bacteria in chronic sinusitis in adults as a part of a prospective microbiological study.Materials and methodsOver a one-year period, aspirations of maxillary sinus secretions and/or ethmoid cavities were derived in n = 79 adult patients with chronic sinusitis by endoscopy in a tertiary-care teaching hospital in Hungary. The qualitative and quantitative compositions of the total cultivable aerobic and anaerobic bacterial and fungal flora cultured on the samples were compared. Correct anaerobic species level identifications were carried out according to standard methods.ResultsBacteria were recovered for all of the 79 aspirates and the numbers of the significant cultured isolates (with colony forming units ≥103) were between 1 and 10. A total of 206 isolates, 106 anaerobic and 100 aerobic or facultative-anaerobic strains were isolated. The most common aerobic bacteria were Streptococcus pneumoniae (n = 40), Haemophilus influenzae (n = 29), Moraxella catarrhalis (n = 6), Staphylococcus aureus (n = 7) and Streptococcus pyogenes (n = 6). The anaerobic bacteria included black-pigmented Prevotella spp. and Porphyromonas spp. (n = 27), Actinomyces spp. (n = 13), Gram-positive anaerobic cocci (n = 16), Fusobacterium spp. (n = 19) and Cutibacterium acnes (n = 8).ConclusionsThis study illustrates the microbial dynamics in which anaerobic and aerobic bacteria prevail and highlights the importance of obtaining cultures from patients with chronic sinusitis for guidance in selection of proper antimicrobial therapy.

Bioaugmentation with Enterococcus casseliflavus: A Hydrogen-Producing Strain Isolated from Citrus Peel Waste

To isolate, identify and characterize an anaerobic strain from in natura CPW, in relation to the consumption of different carbon sources, growth kinetics and H2 production after bioaugmentation. Several substrates were evaluated (glucose, fructose, sucrose, xylose, starch, cellobiose, cellulose and lactose), and its optimal concentration was evaluated by Experimental Design method, besides the application of the isolated strain in citrus peel waste (CPW). A facultative anaerobic strain, similar (99%) to Enterococcus casseliflavus, was isolated from in natura citrus pulp and bagasse. Xylose was the monomer from which there was greater H2 production (10.3 mmol L−1). For 0.5 to 6.5 gxylose L−1, 3.0 to 12.9 mmol H2 L−1 was obtained, respectively. Generation time (Tg) of 0.35 h and specific growth (µ) of 1.98 h−1 for pH 7.0, 37 °C and 2 g glucose L−1 was obtained for E. casseliflavus. In bioaugmentation assays (CPW + E. casseliflavus), highest maximum H2 production potential (P = 13.9 mmol L−1), maximum H2 production rate (Rm = 1.09 mmol h−1) and time to start the H2 production (λ = 2.12 h−1) was observed when compared to glucose (P = 9.1 mmol L−1; Rm = 1.99 mmol h−1; λ = 4.08 h−1). From glucose, there was prevalence of butyric acid pathway (759 mg L−1) in relation to acetic acid (303 mg L−1). From CPW, there was higher production of acetic acid (878 mg L−1) in relation to butyric (147 mg L−1). The application of E. casseliflavus by bioaugmentation is an alternative for biodigestion of complex substrates, such as CPW, to obtain products of biotechnological interest.

Chryseobacterium lacus sp. nov. Isolated From the Surface Water of Two Lakes With Light-Induced Carotenoid Production.

Two Gram-stain-negative, rod-shaped, gliding, catalase-positive, and facultative anaerobic strains, YLOS41T and XH07, were isolated from surface water of Yilong Lake and West Lake of Dali in Yunnan Province, respectively. Both strains were yellow-colored under light conditions and white-colored under dark conditions. The results of physiological and chemotaxonomic characterization, sequencing and phylogenetic analysis, and draft genome sequence comparison demonstrated that the two strains represented a single novel species within the genus Chryseobacterium, for which the name Chryseobacterium lacus sp. nov. is proposed. The type strain is YLOS41T (= KCTC 62352T = MCCC 1H00300T), and the second strain is XH07 (= KCTC 62993). During the cultivation process, we found that the colony color of the two strains changed from white to yellow with illumination. The study investigated the effects of light irradiation on the strain YLOS41T. Results showed that light irradiation did not affect the growth of cells but significantly increased carotenoid synthesis, which caused the change of colony color. In-depth metabolic analysis was conducted by transcriptome. The predominant changes were found for genes involved in carotenoid synthesis as protection from light damage. Based on the genome and transcriptome, we proved that strain YLOS41T possessed a complete synthetic pathway of carotenoid and speculated that the production was zeaxanthin. This was the first report of Chryseobacterium species with light-induced carotenoid synthesis. This study enhances our present knowledge on how Chryseobacterium species isolated from surface water responds to light damage.

Denitrification characteristics and pathways of a facultative anaerobic denitrifying strain, Pseudomonas denitrificans G1

Excessive nitrate in aquaculture systems has attracted wide attention. To isolate novel aerobic denitrifying strain and characterize its nitrogen removal processes, a facultative anaerobic denitrification bacterium, identified as Pseudomonas denitrificans G1, was isolated from marine sediments. Strain G1 could grow and remove 90-98% of nitrate and 97-99% of nitrite under an aerobic or anaerobic condition in 24h, with the total nitrogen removal rate of 33-38% (87-100mg/L). The highest denitrification rate could reach 15.1 mg/(L·h). The suitable condition for the denitrification of G1 is C/N ratio 5-22, dissolved oxygen 0-4.68mg/L, salinity 0-30g NaCl/L, pH 7-9.5. Under the aerobic condition, G1 grew fast; however, the mass spectrographic analysis showed that the gas product was N2O. Under the anaerobic conditions, G1 grow relatively slowly, but could also achieve effective denitrification and the final product was N2. In denitrification of aquaculture wastewater, strain G1 can remove 60.57% of nitrate and 36.36% of total nitrogen; meanwhile, there was a slight accumulation of ammonia nitrogen. P.denitrificans strain G1 has potential in denitrification processes for the treatment of aquaculture wastewater. However, the regulation of reaction conditions and gas products needs to be further studied.