Regulation of nitrile-hydratase synthesis in a Brevibacterium species

The regulation of nitrile-hydratase biosynthese was studied in Brevibacterium sp R 312. Enzyme biosynthesis was not influenced by any carbon and nitrogen source used in the growth medium. It was, however, repressed by amide and amide analogues. Acetamide repressed nitrile-hydratase biosynthesis and induced the wide-spectrum amidase. Therefore, it appeared reasonable to hypothesize a single repressor gene for the nitrile-hydratase/wide-spectrum amidase system.     

Brevibacterium sp. from poultry

Two isolates of methanethiol producing coryneform bacteria sharing morphological and physiological similarities with Brevibacterium are described. They were isolated from bumble-foot-like manifestations of poultry but proved to be non-pathogenic for experimental animals.     

Three New Species of Brevibacteria,Brevibacterium antiquum sp. nov., Brevibacterium aurantiacum sp. nov., and Brevibacterium permense sp. nov.

This work deals with the taxonomic study of orange-pigmented bacteria isolated from permafrost sediments, rice plots, and soils contaminated with wastes from the chemical and salt industries that were assigned to the genus Brevibacterium on the basis of phenotypic characteristics, as well as of some strains described previously as Brevibacterium linens. The study revealed three genomic species, whose members and the type strains of the closest species of Brevibacterium had DNA similarity levels between 24 and 59%. The strains of the genomic species differed from each other and from the known species of Brevibacterium in some physiological and biochemical characteristics, as well as in the sugar and polyol composition of their teichoic acids. The 16S rDNA sequence analysis confirmed the assignment of the environmental isolates to the genus Brevibacterium and showed the phylogenetic distinction of the three genomic species. The results obtained in this study allow three new Brevibacterium species to be described: Brevibacterium antiquum (type strain VKM Ac-2118^T = UCM Ac-411^T), Brevibacterium aurantiacum (type strain VKM Ac-2111^T = NCDO 739^T = ATCC 9175^T), and Brevibacterium permense (type strain VKM Ac-2280^T = UCM Ac-413^T).     

Three new species of brevibacteria--Brevibacterium antiquum sp. nov., Brevibacterium aurantiacum sp. nov. and Brevibacterium permense sp. nov

This work deals with the taxonomic study of 12 orange-pigmented bacteria isolated from permafrost sediments, rice plots, and soils contaminated with wastes from the chemical and salt industries, which were assigned to the genus Brevibacterium on the basis of phenotypic characteristics, as well as of some strains described previously as Brevibacterium linens. The study revealed three genomic species, whose members and the type strains of the closest species of Brevibacterium had DNA similarity levels between 24 and 59%. The strains of the genomic species differed from each other and from the known species of Brevibacterium in some physiological and biochemical characteristics, as well as in the sugar and polyol composition of their teichoic acids. The 16S rDNA sequence analysis confirmed the assignment of the environmental isolates to the genus Brevibacterium and showed the phylogenetic distinction of the three genomic species. The results obtained in this study allow three new Brevibacterium species to be described: Brevibacterium antiquum (type strain VKM Ac-2118T = UCM Ac-411T), Brevibacterium aurantiacum (type strain VKM Ac-2111T = NCDO 739T = ATCC 9175T), and Brevibacterium permense (type strain VKM Ac-2280T = UCM Ac-413T).     

Cloning of the wide spectrum amidase gene from Brevibacterium sp. R312 by genetic complementation. Overexpression in Brevibacterium sp. and Escherichia coli

Abstract The amiE gene of Brevibacterium sp. R312 encoding wide spectrum amidase was isolated by complementation of a Brevibacterium sp. mutant using a plasmid gene bank of chromosomal DNA. The amiE structural gene and its promoter were localized on a 1.8-kb fragment by subsequent subcloning and complementation studies. In Brevibacterium sp., the investigation of amidase activities related to one copy of the gene suggested that the regulation of the amiE gene expression was under negative control. High expression levels have been obtained in Brevibacterium sp. and, after substitution of the amiE promoter by the tac promoter, in Escherichia coli .     

Formation of Desthiobiotin from Oleic Acid by Brevibacterium sp.

Microbial formation of biotin-vitamers from oleic acid was investigated. Many strains of bacteria which were able to utilize oleic acid as a sole carbon source were isolated from soils and other natural materials. Among these bacteria, some strains formed a biotin-vitamer from oleic acid in the culture broth during the cultivation. The vitamer was purified from the culture broth of strain No. 23, and identified as desthiobiotin by chromatographical and biological methods.

From the results of investigation on the taxonomical characteristics, the bacterial strain No. 23 was assumed to be Brevibacterium sp.     

Purification and Properties of Cyclodextrin Glucanotransferase from Brevibacterium sp. No. 9605

Cyclodextrin glucanotransferase (EC 2.4.1.19) from Brevibacterium sp. No. 9605 was purified to homogeneity by chromatography on butyl-Toyopearl 650M, γ-cyclodextrin-Sepharose 4B, and Toyopearl HW-55S. The molecular weight of the purified enzyme was estimated to be 75,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point of the purified enzyme was 2.8. The optimum pH and temperature were pH 10 and 45°C, respectively. The enzyme was stable at the range of pH 6–8 and at temperatures 50°C or less in the presence of CaCl₂. The enzyme produced mainly γ-cyclodextrin from starch in the initial stage of reaction, but later, the proportion of β-cyclodextrin was increased.     

Purification and properties of three esterases from Brevibacterium sp. R312

C. LAMBRECHTS, J. ESCUDERO AND P. GALZY. 1995. The esterases of Brevibacterium sp. R312 were found to have an intracellular location. Electrophoresis of lysed cell supernatant fluids revealed seven bands of esterase activity in the presence of α-naphthyl acetate. Eight esterases were separated by anion exchange chromatography. The three main esterases (esterase 4b, 2 and 4a) of Brevibacterium sp. R312 were purified. The molar masses, the pH optima, the temperature optima and heat stabilities were determined. Esterase 2 differed from the two others in sensitivity to inhibitors. Esterase 4b differed from esterases 2 and 4a in its substrate specificity. This enzyme hydrolyses aliphatic and nitrophenyl esters. The spectrum of activity of the two other esterases is narrower. They hydrolysed only naphthyl esters and, in the case of esterase 2, tributyrate and ethyl butyrate.     

Growth stimulation of Brevibacterium sp. by siderophores

AIMS: To assess which types of siderophores are typically produced by Brevibacterium and how siderophore production and utilization traits are distributed within this genus. METHODS AND RESULTS: During co-cultivation experiments it was found that growth of B. linens Br5 was stimulated by B. linens NIZO B1410 by two orders of magnitude. The stimulation was caused by the production of hydroxamate siderophores by B. linens NIZO B1410 that enabled the siderophore-auxotrophic strain Br5 to grow faster under the applied iron-limited growth conditions. Different patterns of siderophore production and utilization were observed within the genus Brevibacterium. These patterns did not reflect the phylogenetic relations within the group as determined by partial 16S rDNA sequencing. Most Brevibacterium strains were found to utilize hydroxamate siderophores. CONCLUSIONS: Brevibacteria can produce and utilize siderophores although certain strains within this genus are siderophore-auxotrophic. SIGNIFICANCE AND IMPACT OF THE STUDY: It is reported for the first time that brevibacteria produce and utilize siderophores. This knowledge can be utilized to stimulate growth of auxotrophic strains under certain conditions. Enhancing the growth rate of Brevibacterium is of importance for the application of this species, for example, for cheese manufacturing or for industrial production of enzymes or metabolites.     

Degradation of dibenzothiophene by Brevibacterium sp.DO

Dibenzothiophene, a polycyclic aromatic sulfur heterocycle, represents as a model compound the organic sulfur integrated in the macromolecular coal matrix. A pure culture of a Brevibacterium species was isolated, which is able to use dibenzothiophene as sole source of carbon, sulfur and energy for growth. During dibenzothiophene utilization sulfite was released in a stoichiometrical amount and was further oxidized to sulfate. Three metabolites of dibenzothiophene degradation were isolated and identified as dibenzothiophene-5-oxide, dibenzothiophene-5-dioxide and benzoate by cochromatography, UV spectroscopy and gas chromatographymass spectrometry analyses. Based on the identified metabolites a pathway for the degradation of dibenzothiophene by Brevibacterium sp. DO is proposed.Non-standard abbreviations DBT dibenzothiophene - PASH polycyclic aromatic sulfur heterocycle - PAH polycyclic aromatic hydrocarbons - GC-MS gas chromatography-mass spectrometry - HPLC high pressure liquid chromatography - IC ion chromatography     

超声波促进胆固醇的分散对短杆菌产酶的影响

通过超声波分散胆固醇过程,研究了各工艺参数超声波剂量、处理时间、胆固醇添加量和乳化剂量等对胆固醇氧化酶产量和残留胆固醇量的影响。结果表明,当超声波剂量为2．5W／mL,胆固醇3．5‰～4.0‰,吐温-800．3％,20min作用培养基时酶活达到最高。     

The influence of ionic gradients on flocculation of Brevibacterium sp.

The effects of inhibition of various physiological processes were evaluated with respect to flocculation of Brevibacterium sp. and it was shown that those influencing energy levels improved flocculation. Ionophores, valinomycin and gramicidin, brought about the greatest improvement in both the rate and degree. Valinomycin-induced flocculation was influenced by the concentration of external potassium. These results demonstrate that intracellular ionic gradients exerted an influence on flocculation; dissipation of H⁺ or K⁺ gradients induced a higher level of flocculation.     

Biosynthesis of Carotenoids in Brevibacterium sp. KY-4313

The biosynthesis of 4-keto and 4,4′-diketo carotenoids in Brevibacterium sp. KY-4313 was studied. Echinenone and canthaxanthin were isolated from the cultures grown on a medium containing several n-alkanes. When glutathione was added to the bacterial cultures, the formation of canthaxanthin was inhibited while β-carotene and its hydroxy derivatives accumulated. It is suggested that these 4-hydroxy compounds, isocryptoxanthin, isozeaxanthin, and 4-hydroxy-4′-keto-β-carotene, are intermediates in the biosynthesis of canthaxanthin. In the presence of 2-(4-chlorophenylthio)-triethylamine hydrochloride or nicotine, lycopene and neurosporene accumulated. The β-carotene level decreased slightly but β-zeacarotene remained unchanged. β-carotene and its derivatives were resynthesized upon removal of the inhibitors. It was concluded that cyclization can take place at either the neurosporene or lycopene level in Brevibacterium sp. KY-4313.     

Amide hydrolyzing potential of amidase from halotolerant bacterium Brevibacterium sp. IIIMB2706

Till date, amidases from halophiles and halotolerant micro-organisms have not been much explored. In the present study, Brevibacterium sp. IIIMB2706 strain was isolated from salt fields of Gujarat, India, using propionitrile as a nitrogen source in the mineral base media and explored for its amidase activity. Amidase from Brevibacterium sp. IIIMB2706 exhibited substrate affinity towards isobutyramide, propionamide and butyramide. The optimum temperature and pH required for its maximum activity was 45?°C and 7.0, respectively. Effect of salt concentration on amidase activity was also studied and maximum activity was observed in presence of 50?g L^?1 NaCl with significant activity up to 200?g L^?1 NaCl which justifies its halotolerant nature. Various organic solvents compatibility profile showed that the enzyme was highly active in presence of 10% methyl alcohol. Henceforth, halotolerant enzymes may find application in industrial processes where substrate requires organic solvents for solubilization.     

Brevibacterium sp. strain CS2: A potential candidate for arsenic bioremediation from industrial wastewater

A multiple metal-resistant Brevibacterium sp. strain CS2, isolated from an industrial wastewater, resisted arsenate and arsenate upto 280 and 40 mM. The order of resistance against multiple metals was Arsenate > Arsenite > Selenium = Cobalt > Lead = Nickel > Cadmium = Chromium = Mercury. The bacterium was characterized as per morphological and biochemical characteristics at optimum conditions (37 ℃ and 7 pH). The appearance of brownish color precipitation was due to the interaction of silver nitrate confirming its oxidizing ability against arsenic. The strain showed arsenic processing ability at different temperatures, pH, and initial arsenic concentration which was 37% after 72 h and 48% after 96 h of incubation at optimum conditions with arsenite 250 mM/L (initial arsenic concentration). The maximum arsenic removal ability of strain CS2 was determined for 8 days, which was 32 and 46% in wastewater and distilled water, respectively. The heat-inactivated cells of the isolated strain showed a bioremediation efficiency (E) of 96% after 10 h. Genes cluster (9.6 kb) related to arsenite oxidation was found in Brevibacterium sp. strain CS2 after the genome analysis of isolated bacteria through illumine and nanopore sequencing technology. The arsenite oxidizing gene smaller subunit (aioB) on chromosomal DNA locus (Prokka_01508) was identified which plays a role in arsenite oxidation for energy metabolism. The presence of arsenic oxidizing genes and an efficient arsenic oxidizing potential of Brevibacterium sp. strain CS2 make it a potential candidate for green chemistry to eradicate arsenic from arsenic-contaminated wastewater.     

甾短杆菌胆固醇氧化酶基因在大肠杆菌中的表达

为了实现胆固醇氧化酶在大肠杆菌中的表达,将甾短杆菌Brevibacterium sp．DGCDC-82胆固醇氧化酶基因用PCR的方法去掉信号肽序列,连接到质粒pTrc99a,遗过筛选得到了表达胆固醇氧化酶的重组菌JMl09／pTrc99a—COD。经IPTG诱导后表达出相对分子质量约为5．5×10^4的蛋白质。分别考察了诱导温度、时间、IPTG浓度等因素对重组菌表达的胆固醇氧化酶的影响。在优化条件下,该胆固醇氧化酶的酶活可以达到700U／L。酶学特性分析表明其反应的最适pH为7．5,最适温度为40℃。