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1.
Gonzalez-Contreras P Weijma J Buisman CJ 《Applied microbiology and biotechnology》2012,93(3):1295-1303
The extreme acid conditions required for scorodite (FeAsO4·2H2O) biomineralization (pH below 1.3) are suboptimal for growth of most thermoacidophilic Archaea. With the objective to develop
a continuous process suitable for biomineral production, this research focuses on growth kinetics of thermoacidophilic Archaea
at low pH conditions. Ferrous iron oxidation rates were determined in batch-cultures at pH 1.3 and a temperature of 75°C for
Acidianus sulfidivorans, Metallosphaera prunea and a mixed Sulfolobus culture. Ferrous iron and CO2 in air were added as sole energy and carbon source. The highest growth rate (0.066 h−1) was found with the mixed Sulfolobus culture. Therefore, this culture was selected for further experiments. Growth was not stimulated by increase of the CO2 concentration or by addition of sulphur as an additional energy source. In a CSTR operated at the suboptimal pH of 1.1, the
maximum specific growth rate of the mixed culture was 0.022 h−1, with ferrous iron oxidation rates of 1.5 g L−1 d−1. Compared to pH 1.3, growth rates were strongly reduced but the ferrous iron oxidation rate remained unaffected. Influent
ferrous iron concentrations above 6 g L−1 caused instability of Fe2+ oxidation, probably due to product (Fe3+) inhibition. Ferric-containing, nano-sized precipitates of K-jarosite were found on the cell surface. Continuous cultivation
stimulated the formation of an exopolysaccharide-like substance. This indicates that biofilm formation may provide a means
of biomass retention. Our findings showed that stable continuous cultivation of a mixed iron-oxidizing culture is feasible
at the extreme conditions required for continuous biomineral formation. 相似文献
2.
Rob Uche Onyenwoke R. Geyer Juergen Wiegel 《Extremophiles : life under extreme conditions》2009,13(4):687-693
An NAD(P)H-dependent oxidoreductase has been purified approximately 40-fold from the soluble protein fraction of the dissimilatory
iron-reducing, anaerobic, thermophilic bacterium Carboxydothermus ferrireducens. The enzyme, a flavoprotein, has broad-substrate specificity—reducing Fe3+, Cr6+, and AQDS with rates of 0.31, 0.33, and 3.3 U mg−1 protein and calculated NADH oxidation turnover numbers of 0.25, 0.25, and 2.5 s−1, respectively. Numerous quinones are reduced via a two-electron transfer from NAD(P)H to quinone, thus participating in managing
oxidative stress by avoiding the formation of semiquinone radicals. 相似文献
3.
In a greenhouse study, with and without rice plants, of five flooded Philippine rice soils whose organic C (OC) content varied
from 0.5 to 3.6%, incorporation ofSesbania rostrata, Azolla microphylla and rice straw affected the kinetics of soil solution NH
4
+
−N, K+, Fe2+, Mn2+, Zn2+, and P. Sesbania and Azolla increased NH
4
+
−N concentration above the control treatment, whereas rice straw depressed it. In all soils Azolla released less NH
4
+
−N than Sesbania. The apparent net N release depended on the soil and ranged from 44–81% for Sesbania and 27–52% for Azolla.
These effects persisted throughout the growth of IR36. Soil solution and exchangeable NH
4
+
−N increased initially but levelled off between 30 to 80 days and between 20 to 40 days after flooding (DF), respectively.
With rice, soil solution NH
4
+
−N concentration, reached a peak at 15–40 DF and declined to very low levels (<4mg L−1). In the 3 soils of low OC content nitrogen derived from green manure ranged from 34–53% and the apparent revovery of added
green manure N varied from 29–67%. Almost all N released from both Azolla and Sesbania were recovered in the rice plant in
all soils except Concepcion with only 77%. The concentration of K+, Fe2+, Mn2+ and P in the soil solution were higher with rice straw than Sesbania and Azolla in all soils except Hanggan which showed
no change in Fe2+ and Mn2+ but increased K+ and P. In general, rice straw, Sesbania and Azolla decreased Zn2+ concentration in all soils. 相似文献
4.
Qingxin Zhao Sheng Yuan Yuling Zhang Hong Zhu Chuanchao Dai Fang Yang Fengmin Han 《World journal of microbiology & biotechnology》2007,23(8):1057-1064
Pectate lyase A (PelA) of Aspergillus nidulans was successfully expressed in Escherichia coli and effectively purified using a Ni2+-nitrilotriacetate-agarose column. Enzyme activity of the recombinant PelA could reach 360 U ml−1 medium. The expressed PelA exhibited its optimum level of activity over the range of pH 7.5–10 at 50°C. Mn2+, Ca2+, Fe2+, Mg2+ and Fe3+ ions stimulated the pectate lyase activity, but Cu2+ and Zn2+ inhibited it. The recombinant PelA had a V
max of 77 μmol min−1 mg−1 and an apparent K
m of 0.50 mg ml−1 for polygalacturonic acid. Low-esterified pectin was the optimum substrate for the PelA, whereas higher-esterified pectin
was hardly cleaved by it. PelA efficiently macerated mung bean hypocotyls and potato tuber tissues into single cells. 相似文献
5.
In the absence of added Fe2+, the ATPase activity of isolatedSchizosaccharomyces pombe plasma membranes (5–7 μmolP
i per mg protein per min) is moderately inhibited by H2O2 in a concentration-dependent manner. Sizable inactivation occurs only at 50–80 mmol/L H2O2. The process, probably a direct oxidative action of H2O2 on the enzyme, is not induced by the indigenous membrane-bound iron (19.3 nmol/mg membrane protein), is not affected by the
radical scavengers mannitol and Tris, and involves a decrease of both theK
m of the enzyme for ATP and theV of ATP splitting. On exposing the membranes to the Fenton reagent (50 μmol/L Fe2+ +20 mmol/L H2O2), which causes a fast production of HO− radicals, the ATPase is 50–60% inactivated and 90% of added Fe2+ is oxidized to Fe3+ within 1 min. The inactivation occurs only when Fe2+ is added before H2O2 and can thus bind to the membranes. The lack of effect of radical scavengers (mannitol, Tris) indicates that HO− radicals produced in the bulk phase play no role in inactivation. Blockage of the inactivation by the iron chelator deferrioxamine
implies that the process requires the presence of Fe2+ ions bound to binding sites on the enzyme molecules. Added catalase, which competes with Fe2+ for H2O2, slows down the inactivation but in some cases increases its total extent, probably due to the formation of the superoxide
radical that gives rise to delayed HO− production. 相似文献
6.
A novel bacterial strain, designated NA-09T, was isolated from a freshwater sample collected from the Cheonho reservoir, Republic of Korea. Colonies were creamy-white
pigmented, translucent, and circular with convex shape. The isolate was Gram-staining negative, strictly aerobic, motile,
and rod-shaped. The 16S rRNA gene sequence analysis revealed that strain NA-09T belonged to the genus Arenimonas and showed the highest sequence similarities with Arenimonas malthae CC-JY-1T (95.4%), A. oryziterrae YC6267T (94.9%), A. composti P2-12-1T (94.8%), and A. donghaensis H03-R19T (94.1%). The major fatty acids were iso-C16:0 (20.8%), iso-C15:0 (16.9%), summed feature 1 (13.2%), and iso-C16:1
ω7c alcohol (10.2%). The major isoprenoid quinone of the isolate was ubiquionone-8. On the basis of the data from the polyphasic
characterization, the strain NA-09T represents a novel species, for which the name Arenimonas aquaticum sp. nov. is proposed (type strain NA-09T =KACC 14663T =NBRC 106550T). 相似文献
7.
In this work, the effects of iron ion intercalations on lead–tellurate glasses were investigated via FTIR, Raman and UV-Vis
spectroscopies. This homogeneous glass system has compositions xFe2O3·(100−x)[4TeO2·PbO2], where x = 0–60 mol%. The presented observations in these mechanisms show that the lead ions have a pronounced affinity towards [TeO3] structural units, resulting in the deformation of the Te–O–Te linkages, and leading to the intercalation of [PbO
n
] (n = 3, 4) and [FeO
n
] (n = 4, 6) entities in the [TeO4] chain network. The formation of negatively charged [FeO4]1− structural units implies the attraction of Pb2+ ions in order to compensate for this electrical charge. Upon increasing the Fe2O3 content to 60 mol%, the network can accommodate an excess of oxygen through the formation of [FeO6] structural units and the conversion of [TeO4] into [TeO3] structural units. For even higher Fe2O3 contents, Raman spectra indicate a greater degree of depolymerization of the vitreous network than FTIR spectra do. The bands
due to the Pb–O bond vibrations are very strongly polarized and the [TeO4] structural units convert into [TeO3] units via an intermediate coordination stage termed “[TeO3+1]” structural units. Our UV-Vis spectroscopic data show two mechanisms: (i) the conversion of the Fe3+ to Fe2+ at the same time as the oxidation of Pb2+ to Pb+4 ions for samples with low Fe2O3 contents; (ii) when the Fe2O3 content is high (x ≥ 50 mol%), the Fe2+ ions capture positive holes and are transferred to Fe3+ ions through a photochemical reaction, while the Pb2+ ions are formed by the reduction of Pb4+ ions. DFT calculations show that the addition of Fe2O3 to lead–tellurate glasses seems to break the axial Te–O bonds, and the [TeO4] structural units are gradually transformed into [TeO3+1]- and [TeO3]-type polyhedra. Analyzing these data further indicates a gradual conversion of the lead ions from covalent to ionic environment.
There is then a charge transfer between the tri- and tetracoordinated tellurium atoms due to the capacity of the lead–tellurate
network to form the appropriate coordination environments containing structural units of opposite charge, such as iron ions,
[FeO4]1−. 相似文献
8.
A procedure for rapid (7–10 days) obtaining of enrichment cultures of aboriginal thermoacidophilic microbial communities from
ores with high antimony content (Sb 26%) was developed. This technique allows for rapid alkalization of the medium due to
the abundance of calcites, as well as the low antioxidant status of the initial cells. The ore concentration in the medium
was gradually increased to 10 g/l. In the course of this process, selection of enrichment cultures containing microbial strains
preferentially oxidizing ore, S0, or Fe2+ is carried out. A combination of three enrichment cultures allowed us to rapidly (in six days) adapt the aboriginal strains
to high-density pulp (16%) in the reactor at 46°C, as well as to carry out a three-stage semi-continuous cultivation in the
reactors at D = 0.0042 h−1 and to isolate from each reactor the pure cultures of predominant bacteria involved in the process of bioleaching/oxidation
of the mixture of antimonite-containing ores and sulfide flotation concentrates. It was demonstrated that, in the microbial
community of reactor I, strain Sb-K exhibiting high rates of growth and initial substrate oxidation was predominant. In reactor
II, strain Sb-F prevailed, showing a high substrate specificity with respect to Fe2+. A sulfur-oxidizing strain involved in active oxidation of reduced inorganic sulfur compounds (RISCs) was predominant in
reactor III. Nevertheless, together, all three strains showed synergism and were able to oxidize S0, Fe2+, and sulfide minerals (including antimonite Sb2S3 in the presence of 0.02% yeast extract) in reactors. The strains differed from each other in their DNA restriction profiles,
growth rates, and the rates of inorganic substrate oxidation under mixotrophic conditions. The phenotypic properties of all
the studied isolates have a certain similarity to those of sulfobacilli. 相似文献
9.
Metabolism of EDTA and its metal chelates by whole cells and cell-free extracts of strain BNC1 总被引:5,自引:0,他引:5
The influence of metal ions on the metabolism of ethylenediaminetetraacetate (EDTA) by whole cells and cell-free extracts
of strain BNC1 was investigated. Metal-EDTA chelates with thermodynamic stability constants below 1012 were readily mineralized by whole cells with maximum specific turnover rates of 15 (MnEDTA) to 20 (Ca-, Mg-, and BaEDTA)
μmol g protein−1 min−1. With the exception of ZnEDTA, chelates with stability constants greater than 1012 were not oxidized at a significant rate. However, it was shown for Fe(III)EDTA that even strong complexes can be degraded
after pretreatment by addition of calcium and magnesium salts in the pH range 9–11. The range of EDTA chelates converted by
cell-free extracts of strain BNC1 did not depend on their thermodynamic stabilities. The EDTA chelates of Ba2+, Co2+, Mg2+, Mn2+, and Zn2+ were oxidized whereas Ca-, Cd-, Cu-, Fe-, Pb-, and SnEDTA were not. The first catabolic enzyme appears to be an EDTA monooxygenase
since it requires O2, NADH, and FMN for its activity and yields glyoxylate and ethylenediaminetriacetate as products. The latter is further degraded
via N,N′-ethylenediaminediacetate. The maximum specific turnover rate with MgEDTA, the favoured EDTA species, was 50–130 μmol g protein−1 min−1, and the K
m value was 120 μmol/l (K
s for whole cells = 8 μmol/l). Whole cells as well as cell-free extracts of strain BNC1 also converted several structural analogues
of EDTA.
Received: 4 July 1997 / Received revision: 25 September 1997 / Accepted: 29 September 1997 相似文献
10.
EstA was purified from the supernatant by A. lwoffii 16C-1. Its molecular mass was determined to be 45 kDa, and the optimal activity occurred when the pH level was 8.0 at a temperature
of 37°C. The activation energies for the hydrolysis of p-nitrophenyl butyrate was determined to be 11.25 kcal/mol in the temperature range of 10–37°C. The enzyme was unstable at
temperatures higher than 50°C. The Michaelis constant (K
m
) and V
max for p-nitrophenyl butyrate were 11 μM and 131.6 μM min−1 mg of protein-1, respectively. The enzyme was strongly inhibited by Hg2−, Ca2+, Mg2+, Fe2+, Cu2+, Zn2+, Mn2+, Co2+, ethylemediaminetetraacetic acid (EDTA), phenylmethylsulfonyl fluoride (PMSF), and diisopropyl fluorophosphate (DFP).
Received: 20 August 2001 / Accepted: 20 September 2001 相似文献
11.
Luo H Wang Y Wang H Yang J Yang Y Huang H Yang P Bai Y Shi P Fan Y Yao B 《Applied microbiology and biotechnology》2009,82(3):453-461
Using degenerate polymerase chain reaction (PCR) and thermal asymmetric interlaced PCR, a 1,347-bp full-length complementary
DNA fragment encompassing the gene man5A, which encodes a 429-amino acid β-mannanase with a calculated mass of 46.8 kDa, was cloned from acidophilic Bispora sp. MEY-1. The deduced amino acid sequence (catalytic domain) displayed highest identity (54.1%) with the Emericella nidulans endo-β-1,4-d-mannanase, a member of the glycoside hydrolase family 5. Recombinant MAN5A was overexpressed in Pichia pastoris, and its activity in the culture medium reached 500 U ml−1. The enzyme was acidophilic, with highest activity at pH 1.0–1.5, lower than any known mannanases, and optimal temperature
for activity was 65°C. MAN5A had good pH adaptability, excellent thermal and pH stability, and high resistance to both pepsin
and trypsin. The specific activity, K
m, and V
max for locust bean gum substrate was 3,373 U mg−1, 1.56 mg ml−1, and 6,587.6 μmol min−1 mg−1, respectively. The enzymatic activity was not significantly affected by ions such as Ca2+, Cr3+, Co2+, Zn2+, Na+, K+, and Mg2+ and enhanced by Ni2+, Fe3+, Mn2+ and Ag+. These favorable properties make MAN5A a potential candidate for use in various industrial applications. 相似文献
12.
Human β-mannosidase (MANB) was purified to homogeneity directly from lysosomes by using mannosamine conjugated magnetic (Fe3O4) nanoparticles, DE-52 cellulose, and sephadex G-200 chromatography. Fe3O4 nanoparticles were synthesized and utilized ammonia to attach the amino group on the nanoparticles. The particles were covalently
attached with D-mannosamine by cross linker glutaraldehyde and confirmed by FTIR spectroscopy. In FTIR analysis, the peaks
appeared at 2,356.6 cm−1 for −N = CH linkage and at 3,378.4 cm−1, 3,664.9 cm−1 for −OH groups confirmed the conjugation of D-mannosamine with Fe3O4 nanoparticles. Results showed a single band of 97 kDa of purified MANB in SDS-PAGE. The isoelectric point was 4.5 and the
Km and Vmax values were 2.51 mM and 0.315 μM/min/mg, respectively. The purification fold was 329 with 68% yield. The optimal activity
was at pH 5.0 and 75% activity was stable in 20% glycerol at 4°C. The enzyme activity was inhibited by Ni2+, Zn2+, Cd2+, Cu2+, Mo2+, Ag+1, iodoacetate, SDS, DMF, DMSO, ethanol, and acetone; slightly reduced by Pb2+, Co2+, EDTA, DTT, and β-mercaptoethanol. The activity was not affected by Mg2+, Mn2+, Sn2+, Ca2+, Fe3+, PMSF, Triton X-100, D-mannosamine, D-mannose, D-mannitol, D-glucose, and D-fructose. The homogeneity of MANB enzyme was
further confirmed by 2D-PAGE and immunoblot. This is the first novel report of conjugation of D-mannosamine with Fe3O4 nanoparticles for purification of human MANB enzyme. 相似文献
13.
Huiying Luo Jun Yang Jiang Li Pengjun Shi Huoqing Huang Yingguo Bai Yunliu Fan Bin Yao 《Applied microbiology and biotechnology》2010,86(6):1829-1839
We cloned and sequenced a xylanase gene named xylD from the acidophilic fungus Bispora sp. MEY-1 and expressed the gene in Pichia pastoris. The 1,422-bp full-length complementary DNA fragment encoded a 457-amino acid xylanase with a calculated molecular mass of
49.8 kDa. The mature protein of XYLD showed high sequence similarity to both glycosyl hydrolase (GH) families 5 and 30 but
was more homologous to members of GH 30 based on phylogenetic analysis. XYLD shared the highest identity (49.9%) with a putative
endo-1,6-β-d-glucanase from Talaromyces stipitatus and exhibited 21.1% identity and 34.3% similarity to the well-characterized GH family 5 xylanase from Erwinia chrysanthemi. Purified recombinant XYLD showed maximal activity at pH 3.0 and 60 °C, maintained more than 60% of maximal activity when
assayed at pH 1.5–4.0, and had good thermal stability at 60 °C and remained stable at pH 1.0–6.0. The enzyme activity was
enhanced in the presence of Ni2+ and β-mercaptoethanol and inhibited by some metal irons (Hg2+, Cu2+, Pb2+, Mn2+, Li+, and Fe3+) and sodium dodecyl sulfate. The specific activity of XYLD for beechwood xylan, birchwood xylan, 4-O-methyl-d-glucuronoxylan, and oat spelt xylan was 2,463, 2,144, 2,020, and 1,429 U mg−1, respectively. The apparent K
m and V
max values for beechwood xylan were 5.6 mg ml−1 and 3,622 μmol min−1 mg−1, respectively. The hydrolysis products of different xylans were mainly xylose and xylobiose. 相似文献
14.
Citric acid production from sucrose using a recombinant strain of the yeast Yarrowia lipolytica 总被引:1,自引:0,他引:1
Förster A Aurich A Mauersberger S Barth G 《Applied microbiology and biotechnology》2007,75(6):1409-1417
The yeast Yarrowia lipolytica is able to secrete high amounts of several organic acids under conditions of growth limitation and carbon source excess.
Here we report the production of citric acid (CA) in a fed-batch cultivation process on sucrose using the recombinant Y. lipolytica strain H222-S4(p67ICL1) T5, harbouring the invertase encoding ScSUC2 gene of Saccharomyces cerevisiae under the inducible XPR2 promoter control and multiple ICL1 copies (10–15). The pH-dependent expression of invertase was low at pH 5.0 and was identified as limiting factor of the CA-production
bioprocess. The invertase expression was sufficiently enhanced at pH 6.0–6.8 and resulted in production of 127–140 g l−1 CA with a yield Y
CA of 0.75–0.82 g g−1, whereas at pH 5.0, 87 g l −1 with a yield Y
CA of 0.51 gg−1 were produced. The CA-productivity Q
CA increased from 0.40 g l −1 h−1 at pH 5.0 up to 0.73 g l −1 h−1 at pH 6.8. Accumulation of glucose and fructose at high invertase expression level at pH 6.8 indicated a limitation of CA
production by sugar uptake. The strain H222-S4(p67ICL1) T5 also exhibited a gene–dose-dependent high isocitrate lyase expression
resulting in strong reduction (<5%) of isocitric acid, a by-product during CA production. 相似文献
15.
Gulelat D. Haki Alfredo J. Anceno Sudip K. Rakshit 《World journal of microbiology & biotechnology》2008,24(11):2517-2524
Bacillus sp. GRE1 isolated from an Ethiopian hyperthermal spring produced raw-starch digesting, Ca2+-independent thermostable α-amylase. Enzyme production in shake flask experiments using optimum nutrient supplements and environmental
conditions was 2,360 U l−1. Gel filtration chromatography yielded a purification factor of 33.6-fold and a recovery of 46.5%. The apparent molecular
weight of the enzyme was 55 kDa as determined by SDS-PAGE. Presence or absence of Ca2+ produced similar temperature optima of 65–70°C. The optimum pH was in the range of 5.5–6.0. The enzyme maintained 50% of
its original activity after 45 min of incubation at 80°C and was stable at a pH range of 5.0–9.0. The V
max and K
m values for soluble starch were 42 mg reducing sugar min−1 and 4.98 mg starch ml−1, respectively. Strong inhibitors of enzyme activity included Cu2+, Zn2+ and Fe2+. The enzyme coding gene and the deduced protein translation revealed a characteristic but markedly atypical homology to Bacillus species α-amylase sequences. The enzyme hydrolyzed wheat, corn and tapioca starch granules efficiently below their gelatinization
temperatures. Rather than the higher oligosaccharides normally produced by Bacillus α-amylases operating at high temperatures, maltose was the major hydrolysis product with the present enzyme. 相似文献
16.
Sediment pore water concentrations of Fe2+, Mn2+, NH
inf4
sup+
and CH4 were analyzed from both diver-collected cores and anin situ equilibration device (peeper) in Lake Erie's central basin. Sediment oxygen demand (SOD) was measured at the same station
with a hemispheric chamber (including DO probe and recorder) subtending a known area of sediments. The average SOD was 9.4
mM m−2 day−1 (0.3 g m−2 day−1). From pore water gradients within the near-surface zone, the chemical flux across the interface was calculated indirectly
using Fick's first law modified for sediments. These calculations, using core and peeper gradients, always showed sediment
loss to overlying waters, and variations between the two techniques differed by less than an order of magnitude for Fe2+ and CH4. The transport of these reduced constituents can represent a sizeable oxygen demand, ranging from less than 1% for Fe2+ and Mn2+ to as high as 26% for NH
inf4
sup+
, and 30% for CH4. The average flux of these constituents could account for about a third of the SOD at the sediment-water interface of this
station. 相似文献
17.
Asiya Nazir Rohit Soni H. S. Saini R. K. Manhas B. S. Chadha 《World journal of microbiology & biotechnology》2009,25(7):1189-1197
An endoglucanase (1, 4-β-d glucan glucanohydrolase, EC 3.2.1.4) which was catalytically more active and exhibited higher affinity towards barley β-glucan,
xyloglucan and lichenin as compared to carboxymethylcellulose (CMC) was purified from Aspergillus terreus strain AN1 following ion-exchange and hydrophobic interaction chromatography and gel filtration. The purified enzyme (40-fold) that
apparently lacked a cellulose-binding domain showed a specific activity of 60 μmol mg−1 protein−1 against CMC. The purified enzyme had a molecular weight of 78 and 80 KDa as indicated by sodium dodecyl sulphate–polyacrylamide
gel electrophoresis and gel filtration, respectively, and a pI of 3.5. The enzyme was optimally active at temperature 60°C
and pH 4.0, and was stable over a broad range of pH (3.0–5.0) at 50°C. The endoglucanase activity was positively modulated
in the presence of Cu2+, Mg2+, Ca2+, Na+, DTT and mercaptoethanol. Endoglucanase exhibited maximal turn over number (K
cat) and catalytic efficiency (K
cat/km) of 19.11 × 105 min−1 and 29.7 × 105 mM−1 min−1 against barley β-glucan as substrate, respectively. Hydrolysis of CMC and barley β-glucan liberated cellobiose, cellotriose,
cellotetraose and detectable amount of glucose. The hydrolysis of xyloglucan, however, apparently yielded positional isomers
of cellobiose, cellotriose and cellotetraose as well as larger oligosaccharides. 相似文献
18.
A Gram-negative, aerobic, rod-shaped, and red-pigmented bacterial strain, HMC5104T, was isolated from a solar saltern, found in Jeungdo, Republic of Korea (34°59′47″N 126°10′02″E). The major fatty acids were
summed feature 4 (comprising iso-C17:1 I and/or anteiso-C17:1 B; 37.2%), iso-C15:0 (20.4%), and iso-C17.0 30H (15.3%). The DNA G+C content was 46.0 mol%. The major isoprenoid quinone was menaquinone-7 (MK-7). A phylogenetic tree
based on 16S rRNA gene sequences showed that strain HMC5104T formed a lineage within the genus Pontibacter, and was closely related to Pontibacter korlensis (95.9%), P. roseus (94.9%), and P. actiniarum (94.3%). Similarities to all other Pontibacter species were between 95.9–93.9%. On the basis of the evidence presented in this study, strain HMC5104T represents a novel species of the genus Pontibacter, for which the name Pontibacter salisaro sp. nov. is proposed. The type strain is HMC5104T (=KCTC 22712T = NBRC 105731T). 相似文献
19.
Sulfite-oxidizing enzyme activities were analyzed in cell-free extracts of aerobically grown cells of Acidianus ambivalens, an extremely thermophilic and chemolithoautotrophic archaeon. In the membrane and cytoplasmic fractions, two distinct enzyme
activities were found. In the membrane fraction, a sulfite:acceptor oxidoreductase activity was found [530 mU (mg protein)–1; apparent K
m for sulfite, 3.6 mM]. In the cytoplasmic fraction the following enzyme activities were found and are indicative of an oxidative
adenylylsulfate pathway: adenylylsulfate reductase [138 mU (mg protein)–1], adenylylsulfate:phosphate adenyltransferase [“ADP sulfurylase”; 86 mU (mg protein)–1], adenylate kinase [650 mU (mg protein)–1], and rhodanese [thiosulfate sulfur transferase, 9.2 mU (mg protein)–1]. In addition, 5′,5′′′-P1,P4-di(adenosine-5′) tetraphosphate (Ap4A) synthase and Ap4A pyrophosphohydrolase activities were detected.
Received: 17 August 1998 / Accepted: 29 April 1999 相似文献
20.
Bioaugmentation of Bromoamine Acid Degradation with Sphingomonas xenophaga QYY and DNA Fingerprint Analysis of Augmented Systems 总被引:1,自引:0,他引:1
One high-effective bromoamine acid (1-amino-4-bromoanthraquinone-2-sulfonic acid, BAA) degrading strain was isolated previously
with the ability to use BAA as sole source of carbon and nitrogen. It was identified as Sphingomonas xenophaga QYY by 16S rDNA sequence analysis and physio-biochemical tests. In this study, bioaugmentation of BAA degradation with suspended
and immobilized cells of strain QYY was investigated. The optimal degradation conditions were as follows: temperature 30 °C,
pH 6.0–7.0, 150 rev min−1 and the immobilized cells maintained degradation activity to BAA after 60 days storage at 4 °C. The structure of BAA was
evidently changed according to the analysis of total organic carbon removal of BAA (about 50%) and the UV–VIS spectra changes
during the biodegradation. Bioaugmented systems exhibited stronger abilities degrading BAA than the non-bioaugmented control
ones. And microbial community dynamics of augmented systems was revealed by amplified ribosomal DNA restriction analysis (ARDRA),
a modern DNA fingerprint technique. The results indicated that the microbial community dynamics was substantially changed
throughout the augmentation process. This study suggests that it is feasible and potentially useful to enhance BAA degradation
using bioaugmentation with the immobilized cells of BAA-degrading bacterium. 相似文献