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1.
Zhu Guilan Guo Na Yong Yanan Xiong Yawen Tong Qunyi 《Bioprocess and biosystems engineering》2019,42(5):897-900
Bioprocess and Biosystems Engineering - 2-Deoxy-d-glucose (2-DG) is a non-metabolizable glucose analogue and competitive inhibitor of glycolysis. Effect of 2-DG on gellan gum biosynthesis by... 相似文献
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Hexachlorocyclohexane (HCH) has been banned for use in technologically advanced countries; however, it is still in use in
tropical countries like India. Earlier we reported the degradation of HCH isomers by Sphingomonas paucimobilis within 12 days of incubation. Here we report the role of different factors that could enhance the degradation rate of HCH
isomers. We found that an increase in the cell number from 102 to 108 cells/ml resulted in an increased degradation rate of HCH isomers viz. α, β, γ, and δ-HCH. While α-HCH and γ-HCH disappeared
completely from the medium within 3 days of incubation, a maximum of only 90% and 85% degradation was observed for β and δ-HCH,
respectively. We have also observed that adapted cultures degraded HCH isomers more efficiently than did the normal cultures.
Received: 16 February 2000 / Accepted: 23 May 2000 相似文献
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Oxidation of Methyl-Substituted Naphthalenes: Pathways in a Versatile Sphingomonas paucimobilis Strain 总被引:1,自引:0,他引:1 下载免费PDF全文
Aromatic compounds with alkyl substituents are abundant in fossil fuels. These compounds become important environmental sources of soluble toxic products, developmental inhibitors, etc. principally through biological activities. To assess the effect of methyl substitution on the completeness of mineralization and accumulation of pathway products, an isolate from a phenanthrene enrichment culture, Sphingomonas paucimobilis 2322, was used. Washed cell suspensions containing cells grown on 2,6-dimethylnaphthalene in mineral medium were incubated with various mono-, di-, and trimethylnaphthalene isomers, and the products were identified and quantified by gas chromatography and mass spectrometry. The data revealed enzymes with relaxed substrate specificity that initiate metabolism either by methyl group monoxygenation or by ring dioxygenation. Congeners with a methyl group on each ring initially hydroxylate a methyl, and this is followed by conversion to a carboxyl; when there are two methyl groups on a single ring, the first reaction is aryl dioxygenation of the unsubstituted ring. Intermediates are channeled to primary ring fission via dihydrodiols to form methyl-substituted salicylates. Further evidence that there are multiple pathways comes from the fact that both phthalate and (methyl)salicylate are formed from 2-methylnaphthalene. 相似文献
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Analysis of an exopolysaccharide of Sphingomonas paucimobilis GS-1 (EPS/GS-1) with respect to its rheological properties, cross-linking ability with chrome alum and performance test at
75 ± 5°C revealed its strong suspending ability, shear thinning property, and thixotrophic nature which are required to impart
desirable rheology to drilling mud. The organism fulfilled all the specified requirements and its properties were superior
to those of currently-used XC polymer (a xanthan product) for oil drilling applications. However, EPS/GS-1 was unstable in
the presence of bentonite at 100 ± 5°C during performance tests, in contrast to XC polymer.
Received 14 April 1999/ Accepted in revised form 26 July 1999 相似文献
6.
Summary A new screening technique was used to isolate the bacterium Sphingomonas paucimobilis E2 (DSM 6314), which produces the exopolysaccharide gellan. The productivity was found to be about four times higher than that of the industrially used strain Auromonas elodea (ATCC 31461) it was isolated from. The polysaccharide formation was found to be predominantly growth-related.
Correspondence to: W.-D. Deckwer 相似文献
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A D Davison M R Gillings D R Jardine P Karuso A S Nouwens J J French D A Veal N Altavilla 《Journal of industrial microbiology & biotechnology》1999,23(4-5):314-319
The biphenyl degradation pathway of Sphingomonas paucimobilis BPSI-3 was investigated using a degradation-deficient mutant generated by 1-methyl-3-nitro-1-nitrosoguanidine (NTG) mutagenesis.
The mutant, designated AN2, was confirmed as originating from BPSI-3 through the use of ERIC (Enterobacterial Repetitive Intergenic
Consensus) PCR and by detection of the diagnostic pigment, nostoxanthin, in cellular methanol extracts. Mutant AN2 produced
a yellow followed by red extracellular substance when grown in the presence of biphenyl. In the presence of 2,3-dihydroxybiphenyl,
yellow followed by red then yellow compounds were formed over time. This colour change was consistent with the characteristics
of a quinone, 1-phenyl-2,3-benzoquinone, which could arise from the oxidation of 2,3-dihydroxybiphenyl. A quinone was synthesised
from 2,3-dihydroxybiphenyl and compared to the red compound produced by mutant AN2. Gas chromatography-mass spectrophotometry
(GC-MS) confirmed that a similar quinone (4,5-dimethoxy-3-phenyl-1,2-benzoquinone) compared to the structure of the proposed
biogenic compound, had been formed. This compound was also found after GC-MS analysis of mutant AN2 culture extracts. Spectrophotometric
analysis of the quinone synthesised and the red product produced revealed almost identical spectral profiles. A likely inference
from this evidence is that the mutant AN2 is blocked, or its activity altered, in the first gene cluster, bphA to C, of the biphenyl degradation pathway.
Received 19 April 1999/ Accepted in revised form 25 July 1999 相似文献
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Kaneko A Miyadai H Danbara H Kawahara K 《Bioscience, biotechnology, and biochemistry》2000,64(6):1298-1301
Mutants of Sphingomonaspaucimobilis defective in a part of the carbohydrate moiety of the glycosphingolipid (GSL) were constructed by transposon (Tn5)-insertional mutagenesis. Defective mutants were selected by ELISA using the antibody recognizing the tetrasaccharide-type GSL (GSL-4A) of S. paucimobilis. Eight defective mutants were selected from about 8,000 kanamycin-resistant strains, and seven of them were found to lack the terminal mannose of GSL-4A. The chemical structure of the mutant GSL was investigated, and proved that the rest of the structure was not changed by the mutation. 相似文献
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E Masai Y Katayama S Nishikawa M Fukuda 《Journal of industrial microbiology & biotechnology》1999,23(4-5):364-373
Sphingomonas paucimobilis SYK-6 is able to grow on a wide variety of dimeric lignin compounds. These compounds are degraded via vanillate and syringate
by a unique enzymatic system, composed of etherases, O demethylases, ring cleavage oxygenases and side chain cleaving enzymes.
These unique and specific lignin modification enzymes are thought to be powerful tools for utilization of the most abundant
aromatic biomass, lignin. Here, we focus on the genes and enzymes involved in β-aryl ether cleavage and biphenyl degradation.
Two unique etherases are involved in the reductive cleavage of β-aryl ether. These two etherases have amino acid sequence
similarity with the glutathione S-transferases, and use glutathione as a hydrogen donor. It was found that 5,5′-dehydrodivanillate, which is a typical lignin-related
biphenyl structure, was transformed into 5-carboxyvanillate by the reaction sequence of O-demethylation, meta-ring cleavage, and hydrolysis, and the genes involved in the latter two reactions have been characterized. Vanillate and
syringate are the most common intermediate metabolites in lignin catabolism. These compounds are initially O-demethylated
and the resulting diol compounds, protocatechuate (PCA) and 3-O-methylgallate, respectively, are subjected to ring cleavage catalyzed by PCA 4,5-dioxygenase. The ring cleavage products
generated are further degraded through the PCA 4,5-cleavage pathway. We have isolated and characterized genes for enzymes
involved in this pathway. Disruption of a gene for 2-pyrone-4,6-dicarboxylate hydrolase (ligI) in this pathway suggested that an alternative route for 3-O-methylgallate degradation, in which ligI is not involved, would play a role in syringate catabolism. In this article, we describe the genetic and biochemical features
of the S. paucimobilis SYK-6 genes involved in degradation of lignin-related compounds. A possible application of the SYK-6 lignin degradation system
to produce a valuable chemical material is also described.
Received 01 May 1999/ Accepted in revised form 29 July 1999 相似文献
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E Yabuuchi I Yano H Oyaizu Y Hashimoto T Ezaki H Yamamoto 《Microbiology and immunology》1990,34(2):99-119
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Exopolymers have been associated with the initial adhesion of bacteria, which is the primary step for biofilm formation. Moreover, the polymeric matrix of biofilms has a considerable influence on some of the most important physical and physiological properties of biofilms. The role of extracellular polymers in biofilm formation was studied using three mutants of Sphingomonas paucimobilis with increasing capabilities for exopolymer production. The physical, biochemical and physiological properties of three different layers of each biofilm were determined. The layers were detached by submitting the biofilm to increasing shear stress. The results revealed that the presence of exopolymers in the growth medium was essential for biofilm formation. The mutant producing the highest amount of exopolymer formed very thick biofilms, while the biofilms formed by the medium exopolymer producer were on average 8 times thinner. The lowest exopolymer producer did not form biofilm. In both types of biofilms, exopolymer density increased with depth, although this tendency was more significant in thinner biofilms. Cell distribution was also more heterogeneous in thinner biofilms, exhibiting a greater accumulation of cells in the inner layers. The thicker biofilms had very low activity in the inner layer. This was related to a high accumulation of proteins and DNA in this layer due to cell lysis and hydrolytic activity. Activity in the thin biofilm was constant throughout its depth, suggesting that there was no nutrient limitation. The production of exopolymers by each cell was constant throughout the depth of the biofilms, although it was greater in the case of the higher producer. 相似文献
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Polychlorinated biphenyls (PCBs) are important environmental pollutants and have been found to have adverse effects on a number of different organisms. Aerobic biodegradation of PCBs occurs through direct oxidation of the biphenyl nucleus. Biphenyl degraders are instrumental in the mineralization of PCBs to CO2 and water. Here two bacteria, Alcaligenes faecalis type II strain BPSI-2 and Sphingomonas paucimobilis strain BPSI-3, are described that exhibit synergistic mineralization of biphenyl (using 14 C-UL-biphenyl) when grown as a co-culture. Mineralization rates (23·7 and 9·1 nmol nmol−1 h−1 , respectively) and extent of mineralization (38·1% and 24·4%, respectively) were significantly different between the strains as well as when compared to the co-culture (35·2 nmol nmol−1 h−1 and 45·2%). Both strains were originally isolated from an enrichment culture, BSEN-2. The co-culture of BPSI-2 and 3 showed a threefold increase in mineralization rate compared with the parent culture and a decrease in the time taken for 14 CO2 evolution to occur. There was no significant difference in the extent of mineralization between the co-culture and BSEN-2. Examination of enrichment cultures at the community level may play a role in optimizing bioremediation programmes. 相似文献
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The cell envelope structure of the lipopolysaccharide-lacking gram-negative bacterium Sphingomonas paucimobilis. 总被引:1,自引:0,他引:1 下载免费PDF全文
S Kawasaki R Moriguchi K Sekiya T Nakai E Ono K Kume K Kawahara 《Journal of bacteriology》1994,176(2):284-290
From the cell envelope preparation of Sphingomonas paucimobilis two membrane fractions with different densities were separated by sucrose density gradient ultracentrifugation. The high-density fraction contained several major proteins, phospholipids, and glycosphingolipids, which are the only glycolipids of this lipopolysaccharide-lacking gram-negative bacterium. The low-density fraction showed many minor bands of proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and NADH oxidase activity was localized in this fraction. Combined with morphological data of vesicles formed by these membrane fractions, the high-density and low-density fractions were proposed to be an outer membrane and a cytoplasmic membrane, respectively. The localization of the glycosphingolipid was investigated also by means of immunoelectron microscopic analysis using a glycosphingolipid-specific antibody. The glycosphingolipid was shown to localize at the cell envelope, and the antigenic sugar portion was exposed to the bacterial cell surface. From these results the glycosphingolipid was assumed to have a function similar to that of the lipopolysaccharide of other gram-negative bacteria. 相似文献
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Atul K. Johri Meenakshi Dua Dipika Tuteja Renu Saxena D.M. Saxena Rup Lal 《Biotechnology letters》1998,20(9):885-887
Sphingomonas paucimobilis degrades aerobically , , and -hexachlorocyclohexane. With -HCH, complete degradation occurred after 3 days but with and , and with -HCH, 98 and 56 % degradation occurred after 12 and 8 days of incubation, respectively. Pentachlorocyclohexene was formed as the primary metabolite during the degradation of all the HCH isomers. © Rapid Science Ltd. 1998 相似文献
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In this study, the effect of H2O2-induced oxidative stress on gellan gum production and cell growth were investigated. Gellan gum production was improved and cell growth was inhibited by H2O2. A multiple H2O2 stresses with different concentrations were developed to optimize gellan gum production. A maximal gellan gum yield (22.52 g/L), which was 35.58 % higher than the control, was observed with 2, 2, 3, 4 mmol/L H2O2 added at 6, 12, 18, 24 h, respectively. Moreover, UDP-glucose pyrophosphorylase activity and glucosyltransferase activity were increased with H2O2 stresses. This new strategy of multiple H2O2-induced oxidative stresses would be further applied to gellan gum production in future study. 相似文献
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Prokop Z Monincová M Chaloupková R Klvana M Nagata Y Janssen DB Damborský J 《The Journal of biological chemistry》2003,278(46):45094-45100
Haloalkane dehalogenases are bacterial enzymes capable of carbon-halogen bond cleavage in halogenated compounds. To obtain insights into the mechanism of the haloalkane dehalogenase from Sphingomonas paucimobilis UT26 (LinB), we studied the steady-state and presteady-state kinetics of the conversion of the substrates 1-chlorohexane, chlorocyclohexane, and bromocyclohexane. The results lead to a proposal of a minimal kinetic mechanism consisting of three main steps: (i) substrate binding, (ii) cleavage of the carbon-halogen bond with simultaneous formation of an alkyl-enzyme intermediate, and (iii) hydrolysis of the alkyl-enzyme intermediate. Release of both products, halide and alcohol, is a fast process that was not included in the reaction mechanism as a distinct step. Comparison of the kinetic mechanism of LinB with that of haloalkane dehalogenase DhlA from Xantobacter autotrophicus GJ10 and the haloalkane dehalogenase DhaA from Rhodococcus rhodochrous NCIMB 13064 shows that the overall mechanisms are similar. The main difference is in the rate-limiting step, which is hydrolysis of the alkylenzyme intermediate in LinB, halide release in DhlA, and liberation of an alcohol in DhaA. The occurrence of different rate-limiting steps for three enzymes that belong to the same protein family indicates that extrapolation of this important catalytic property from one enzyme to another can be misleading even for evolutionary closely related proteins. The differences in the rate-limiting step were related to: (i) number and size of the entrance tunnels, (ii) protein flexibility, and (iii) composition of the halide-stabilizing active site residues based on comparison of protein structures. 相似文献
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Gellan gum biosynthesis in Sphingomonas paucimobilis ATCC 31461: genes,enzymes and exopolysaccharide production engineering 总被引:2,自引:0,他引:2
Sá-Correia I Fialho AM Videira P Moreira LM Marques AR Albano H 《Journal of industrial microbiology & biotechnology》2002,29(4):170-176
The commercial gelling agent, gellan, is an extracellular polysaccharide (EPS) produced by Sphingomonas paucimobilis ATCC 31461. In recent years, significant progress in understanding the relationship between gellan structure and properties
and elucidation of the biosynthesis and engineering of this recent product of biotechnology has been made. This review focuses
on recent advances in this field. Emphasis is given to identification and characterization of genes and enzymes involved,
or predicted to be involved, in the gellan biosynthetic pathway, at the level of synthesis of sugar-activated precursors,
of the repeat unit assembly and of gellan polymerization and export. Identification of several genes, biochemical characterization
of the encoded enzymes and elucidation of crucial steps of the gellan pathway indicate that possibilities now exist for exerting
control over gellan production at any of the three levels of its biosynthesis. However, a better knowledge of the poorly understood
steps and of the bottlenecks and regulation of the pathway, the characterization of the composition, structure and functional
properties of gellan-like polymers produced either by the industrial strain under different culture conditions or by mutants
are still required for eventual success of the metabolic engineering of gellan production. Journal of Industrial Microbiology & Biotechnology (2002) 29, 170–176 doi:10.1038/sj.jim.7000266
Received 11 February 2002/ Accepted in revised form 09 April 2002 相似文献
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The haloalkane dehalogenase from Sphingomonas paucimobilis UT26 (LinB) is the enzyme involved in the gamma-hexachlorocyclohexane degradation. This enzyme hydrolyses a broad range of halogenated aliphatic compounds via an alkyl-enzyme intermediate. LinB is believed to belong to the family of alpha/beta-hydrolases which employ a catalytic triad, i.e. nucleophile-histidine-acid, during the catalytic reaction. The position of the catalytic triad within the sequence of LinB was probed by a site-directed mutagenesis. The catalytic triad residues of the haloalkane dehalogenase LinB are proposed to be D108, H272 and E132. The topological location of the catalytic acid (E132) is after the beta-strand six which corresponds to the location of catalytic acid in the pancreatic lipase, but not in the haloalkane dehalogenase of Xanthobacter autotrophicus GJ10 which contains the catalytic acid after the beta-strand seven. 相似文献
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Masai E Yamamoto Y Inoue T Takamura K Hara H Kasai D Katayama Y Fukuda M 《Bioscience, biotechnology, and biochemistry》2007,71(10):2487-2492
The vanillin dehydrogenase gene (ligV), which conferred the ability to transform vanillin into vanillate on Escherichia coli, was isolated from Sphingomonas paucimobilis SYK-6. The ligV gene consists of a 1,440-bp open reading frame encoding a polypeptide with a molecular mass of 50,301 Da. The deduced amino acid sequence of ligV showed about 50% identity with the known vanillin dehydrogenases of Pseudomonas vanillin degraders. The gene product of ligV (LigV) produced in E. coli preferred NAD+ to NADP+ and exhibited a broad substrate preference, including vanillin, benzaldehyde, protocatechualdehyde, m-anisaldehyde, and p-hydroxybenzaldehyde, but the activity toward syringaldehyde was less than 5% of that toward vanillin. Insertional inactivation of ligV in SYK-6 indicated that ligV is essential for normal growth on vanillin. On the other hand, growth on syringaldehyde was only slightly affected by ligV disruption, indicating the presence of a syringaldehyde dehydrogenase gene or genes in SYK-6. 相似文献