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Environmental abuses and subsequent array of health hazards by petroleum products have emerged as a global concern that warrants proper remediation. Pyrene (PYR), a polycyclic aromatic hydrocarbon, is a xenobiotic by-product during crude petroleum processing. Biodegradation potential of two bacterial isolates (MK4 and MK9) of Brevibacterium sediminis from oil contaminated sites was explored. MK4 and MK9 could degrade PYR up to 23 and 59% (1000 mg.L − 1 ), respectively. A first-order formalism with the rate constant for MK4 and MK9 were found to be 0.022 ± 0.001 and 0.081 ± 0.005 day − 1 , respectively with the corresponding half life period of 31.4 ± 1.4 and 8.6 ± 0.60 days respectively. Both the isolates produce biosurfactants as established by drop collapse assay, oil spreading and emulsification activity studies. Decrease in pH, change in absorbance (bacterial growth), and catechol formation support adaptation capability of the isolates to degrade PYR by using it as a source of carbon. PYR ring cleavage was induced by the ring hydroxylating dioxogenase enzyme present in the strains, as identified by PCR assay. In silico analyses of the PYR degrading enzyme revealed its higher binding affinity (-7.6 kcal.mol − 1 ) and stability (Eigen value:1.655763 × 10 − 04 ) to PYR, as further supported by other thoeroretical studies. MK9 strain was more efficient than the MK4 strain in PYR degradation. Studies gain its prominence as it reports for the first time on the aptitude of B. sediminis as novel PYR-degrading agent that can efficiently be used in the bioremediation of petroleum product pollution with a greener approach.

A Gram stain-positive, non-spore-forming, non-motile, short-rod actinomyces strain GXQ1321 T was isolated from maritime surface sediments in Beihai (21° 41′ 21.65″ N, 109° 05′ 76.56″ E), Guangxi Zhuang Autonomous Region, and a number of categorization studies were performed. Following a period of 72 h of incubation at a temperature of 30 °C within a modified actinomycete culture medium, the colony was light-yellow, circular, smooth, central bulge, convex, opaque, with a 1.2–2.3 mm diameter. Strain GXQ1321 T had the ability to degrade cellulose. Chemotaxonomic studies revealed that the major methylnaphthoquinones in strain GXQ1321 T was MK-8(H 2 ). The most prevalent cellular fatty acids were anteiso -C 19:0 , anteiso -C 15:0 , anteiso -C 17:0 , and iso -C 16:0 . The whole-cell sugars of the strain GXQ1321 T were identified rhamnose, xylose and glucose. Meso-diaminopimelic acid was found in the peptidoglycan hydrolysate, and the polar lipids were identified as diphosphatidylglycerol, three phosphoglycolipid, phosphatidylglycerol and two unknown glycolipid. This strain had 69.6% DNA G+C content. Strain GXQ1321 T is classified as Brevibacterium based on its 16S rRNA gene sequence. It is closely related to Brevibacterium samyangense SST-8  T (96.8%) and Brevibacterium rongguiense 5221  T (96.3%). The average nucleotide identity (ANI) values of GXQ1321 T and the above two type strains were 73.9–77.1%, and the digital DNA-DNA hybridisation (dDDH) values were 15.3–21.1%. Based on the phylogenetic, chemotaxonomic and physiological data, strain GXQ1321 T was considered to be a novel species of the genus Brevibacterium , named Brevibacterium litoralis sp. nov, with the type strain GXQ1321 T (= MCCC 1K08964 T  = KCTC 59167  T ).

Gram-positive, aerobic, non-motile, pale-yellow, and rodshaped bacterium, designated as Gsoil 188 T , was isolated from the soil of a ginseng field in Pocheon, South Korea. A phylogenetic analysis based on 16S rRNA gene sequence comparison revealed that the strain formed a distinct lineage within the genus Brevibacterium and was most closely related to B. epidermidis NBRC 14811 T (98.4%), B. sediminis FXJ8.269 T (98.2%), B. avium NCFB 3055 T (98.1%), and B. oceani BBH7 T (98.1%), while it shared less than 98.1% identity with the other species of this genus. The DNA G + C content was 68.1 mol%. The predominant quinone was MK-8(H 2 ). The major fatty acids were anteiso-C 15:0 and anteiso-C 17:0 . The cell wall peptidoglycan of strain Gsoil 188 T contained meso -diaminopimelic acid. The major polar lipids were phosphatidylglycerol, diphosphatidylglycerol, and an unidentified aminolipid. The physiological and biochemical characteristics, low DNA-DNA relatedness values, and taxonomic analysis allowed the differentiation of strain Gsoil 188 T from the other recognized species of the genus Brevibacterium . Therefore, strain Gsoil 188 T represents a novel species of the genus Brevibacterium , for which the name Brevibacterium anseongense sp. nov. is proposed, with the type strain Gsoil 188 T (= KACC 19439 T = LMG 30331 T ).

The strain designated NCCP-602 was isolated from tannery effluent, and displayed aerobic, gram-positive, rod-shaped cells that were characterized by oxidase negative, catalase positive, and non-motile features. The most favourable growth conditions were observed at a temperature of 30°C, pH 7.0, and NaCl concentration of 1% (w/v). It tolerated heavy metals at high concentrations of chromium (3600 ppm), copper (3300 ppm), cadmium (3000 ppm), arsenic (1200 ppm) and lead (1500 ppm). The results of phylogenetic analysis, derived from sequences of the 16S rRNA gene, indicated the position of strain NCCP-602 within genus Brevibacterium and showed that it was closely related to Brevibacterium ammoniilyticum JCM 17537 . Strain NCCP-602 formed a robust branch that was clearly separate from closely related taxa. A comparison of 16S rRNA gene sequence similarity and dDDH values between the closely related type strains and strain NCCP-602 provided additional evidence supporting the classification of strain NCCP-602 as a distinct novel genospecies. The polar lipid profile included diphosphatidylglycerol, glycolipid, phospholipids and amino lipids. MK-7 and MK-8 were found as the respiratory quinones, while anteiso-C , iso-C , iso-C , iso-C , and anteiso-C were identified as the predominant cellular fatty acids (> 10%). Considering the convergence of phylogenetic, phenotypic, chemotaxonomic, and genotypic traits, it is suggested that strain NCCP-602 be classified as a distinct species Brevibacterium metallidurans sp. nov. within genus Brevibacterium with type strain NCCP-602 (JCM 18882  = CGMCC1.62055 ).

In the present study, the strain Brevibacterium frigoritolerans DC2 was explored for the efficient and extracellular synthesis of silver nanoparticles. These biosynthesized silver nanoparticles were characterized by ultraviolet-visible spectrophotometry, which detected the formation of silver nanoparticles in the reaction mixture and showed a maximum absorbance at 420 nm. In addition, field emission transmission electron microscopy revealed the spherical shape of the nanoparticles. The dynamic light scattering results indicated the average particle size of the product was 97 nm with a 0.191 polydispersity index. Furthermore, the product was analyzed by energy dispersive X-ray spectroscopy, X-ray diffraction, and elemental mapping, which displayed the presence of elemental silver in the product. Moreover, on a medical platform, the product was checked against pathogenic microorganisms including Vibrio parahaemolyticus, Salmonella enterica, Bacillus anthracis, Bacillus cereus, Escherichia coli, and Candida albicans. The nanoparticles demonstrated antimicrobial activity against all of these pathogenic microorganisms. Additionally, the silver nanoparticles were evaluated for their combined effects with the commercial antibiotics lincomycin, oleandomycin, vancomycin, novobiocin, penicillin G, and rifampicin against these pathogenic microorganisms. These results indicated that the combination of antibiotics with biosynthesized silver nanoparticles enhanced the antimicrobial effects of antibiotics. Therefore, the current study is a demonstration of an efficient biological synthesis of silver nanoparticles by B. frigoritolerans DC2 and its effect on the enhancement of the antimicrobial efficacy of well-known commercial antibiotics.

The genus Brevibacterium harbors many members important for cheese ripening. We performed real-time quantitative PCR (qPCR) to determine the abundance of Brevibacterium on rinds of Vorarlberger Bergkäse, an Austrian artisanal washed-rind hard cheese, over 160 days of ripening. Our results show that Brevibacterium are abundant on Vorarlberger Bergkäse rinds throughout the ripening time. To elucidate the impact of Brevibacterium on cheese production, we analysed the genomes of three cheese rind isolates, L261, S111, and S22. L261 belongs to Brevibacterium aurantiacum , whereas S111 and S22 represent novel species within the genus Brevibacterium based on 16S rRNA gene similarity and average nucleotide identity. Our comparative genomic analysis showed that important cheese ripening enzymes are conserved among the genus Brevibacterium . Strain S22 harbors a 22 kb circular plasmid which encodes putative iron and hydroxymethylpyrimidine/thiamine transporters. Histamine formation in fermented foods can cause histamine intoxication. We revealed the presence of a putative metabolic pathway for histamine degradation. Growth experiments showed that the three Brevibacterium strains can utilize histamine as the sole carbon source. The capability to utilize histamine, possibly encoded by the putative histamine degradation pathway, highlights the importance of Brevibacterium as key cheese ripening cultures beyond their contribution to cheese flavor production.

l-valine is an essential branched-amino acid that is widely used in multiple areas such as pharmaceuticals and special dietary products and its use is increasing. As the world market for l-valine grows rapidly, there is an increasing interest to develop an efficient l-valine-producing strain. In this study, a simple, sensitive, efficient, and consistent screening procedure termed 96 well plate-PC-HPLC (96-PH) was developed for the rapid identification of high-yield l-valine strains to replace the traditional l-valine assay. l-valine production by Brevibacterium flavum MDV1 was increased by genome shuffling. The starting strains were obtained using ultraviolet (UV) irradiation and binary ethylenimine treatment followed by preparation of protoplasts, UV irradiation inactivation, multi-cell fusion, and fusion of the inactivated protoplasts to produce positive colonies. After two rounds of genome shuffling and the 96-PH method, six l-valine high-yielding mutants were selected. One genetically stable mutant (MDVR2-21) showed an l-valine yield of 30.1 g/L during shake flask fermentation, 6.8-fold higher than that of MDV1. Under fed-batch conditions in a 30 L automated fermentor, MDVR2-21 accumulated 70.1 g/L of l-valine (0.598 mol l-valine per mole of glucose; 38.9% glucose conversion rate). During large-scale fermentation using a 120 m3 fermentor, this strain produced > 66.8 g/L l-valine (36.5% glucose conversion rate), reflecting a very productive and stable industrial enrichment fermentation effect. Genome shuffling is an efficient technique to improve production of l-valine by B. flavum MDV1. Screening using 96-PH is very economical, rapid, efficient, and well-suited for high-throughput screening.

Enantioselective oxidation of racemic phenyl-1,2-ethanediol into ( R )-(−)-mandelic acid by a newly isolated Brevibacterium lutescens CCZU12-1 was demonstrated. It was found that optically active ( R )-(−)-mandelic acid ( e.e.p  > 99.9 %) is produced leaving the other enantiomer ( S )-(+)-phenyl-1,2-ethanediol intact. Using fed-batch method, a total of 172.9 mM ( R )-(−)-mandelic acid accumulated in the reaction mixture after the seventh feed. Moreover, oxidation of phenyl-1,2-ethanediol using calcium alginate-entrapped resting cells was carried out in the aqueous system, and efficient biocatalyst recycling was achieved as a result of cell immobilization in calcium alginate, with a product-to-biocatalyst ratio of 27.94 g ( R )-(−)-mandelic acid g −1 dry cell weight cell after 16 cycles of repeated use.

Certain bacterial enzymes are packaged within protein chambers that provide a confined environment for their reactions to take place. Ban and colleagues now identify a family of proteins that form nanocompartments, similar to bacterial microcompartments such as the carboxysome, and show that the enzymes within are anchored by their C-terminal extensions to binding sites on the inner surface of the chamber. Compartmentalization is an important organizational feature of life. It occurs at varying levels of complexity ranging from eukaryotic organelles and the bacterial microcompartments, to the molecular reaction chambers formed by enzyme assemblies. The structural basis of enzyme encapsulation in molecular compartments is poorly understood. Here we show, using X-ray crystallographic, biochemical and EM experiments, that a widespread family of conserved bacterial proteins, the linocin-like proteins, form large assemblies that function as a minimal compartment to package enzymes. We refer to this shell-forming protein as 'encapsulin'. The crystal structure of such a particle from Thermotoga maritima determined at 3.1-Å resolution reveals that 60 copies of the monomer assemble into a thin, icosahedral shell with a diameter of 240 Å. The interior of this nanocompartment is lined with conserved binding sites for short polypeptide tags present as C-terminal extensions of enzymes involved in oxidative-stress response.

A Gram-positive, aerobic, nonmotile strain, NM2E3(T) was identified as Brevibacterium based on the 16S rRNA gene sequence analysis and had the highest similarities to Brevibacterium jeotgali SJ5-8(T) (97.3 %). This novel bacterium was isolated from root tissue of Prosopis laegivata grown at the edge of a mine tailing in San Luis Potosí, Mexico. Its cells were non-spore-forming rods, showing catalase and oxidase activities and were able to grow in LB medium added with 40 mM Cu(2+), 72 mM As(5+) and various other toxic elements. Anteiso-C15:0 (41.6 %), anteiso-C17:0 (30 %) and iso-C15:0 (9.5 %) were the major fatty acids. MK-8(H2) (88.4 %) and MK-7(H2) (11.6 %) were the major menaquinones. The DNA G + C content of the strain NM2E3(T) was 70.8 mol % (Tm). DNA-DNA hybridization showed that the strain NM2E3(T) had 39.8, 21.7 and 20.3 % relatedness with B. yomogidense JCM 17779(T), B. jeotgali JCM 18571(T) and B. salitolerans TRM 45(T), respectively. Based on the phenotypic and genotypic analyses, the strain NM2E3(T) (=CCBAU 101093(T) = HAMBI 3627(T) = LMG 8673(T)) is reported as a novel species of the genus Brevibacterium, for which the name Brevibacterium metallicus sp. nov., is proposed.