共查询到20条相似文献,搜索用时 15 毫秒
1.
Z-phenylacetaldoxime degradation by a novel aldoxime dehydratase from Bacillus sp. strain OxB-1 总被引:2,自引:0,他引:2
Z-phenylacetaldoxime (Z-PAOx) degrading bacterium, identified as Bacillus sp. strain OxB-1, was isolated from soil after 2 months acclimation. The enzyme involved in the degradation of Z-PAOx was induced by the aldoxime and required FMN for its activity. The enzyme was partially purified from the cell-free extract of the strain and shown to catalyze the stoichiometric dehydration reaction of Z-PAOx to form phenylacetonitrile (PAN). Activities of nitrilase and amidase acting on PAN and phenylacetamide (PAAm), respectively, to form phenylacetate (PAA) were found in the strain grown on Z-PAOx. This is the first report of aldoxime dehydratase co-existing with nitrile degrading enzymes in bacteria. 相似文献
2.
Waldemar Adam Zoltan Lukacs Claudia Kahle Chantu R. Saha-Mller Peter Schreier 《Journal of Molecular Catalysis .B, Enzymatic》2001,11(4-6):377-385
Screening of soil bacteria with allylbenzene resulted in a Bacillus megaterium strain, which hydroxylates simple hydrocarbons in high enantiomeric excess (ee up to 99%). Benzylic and nonbenzylic hydroxylation products were obtained, without the usually observed high preference for the benzylic position. The immobilization of the B. megaterium cells in alginate gel effectively improved the stability of the cells and increased the amounts of products formed, without loss of enantioselectivity. The product ratio ( vs. β hydroxylation) was shifted towards benzylic hydroxylation, which suggests that at least two hydroxylating enzymes with distinct regioselectivity are involved. Comparison to free-cell fermentations in small- and large-scale bioreactors (up to 2000 ml) showed that the use of immobilized cells is advantageous, as they are easier to handle and yield higher amounts of oxidation products. 相似文献
3.
J.R. Robledo-OrtízD.E. Ramírez-Arreola A.A. Pérez-FonsecaC. Gómez O. González-ReynosoJ. Ramos-Quirarte R. González-Núñez 《International biodeterioration & biodegradation》2011,65(3):539-546
Benzene, toluene, and o-xylene (BTX) degradation by immobilized Pseudomonas putida F1 of postconsumer agave-fiber/polymer foamed-composites (AFPFC) and suspended cultures was studied under controlled conditions. Analyses using FTIR-ATR and SEM showed that P. putida F1 adhered onto the composite surface and developed a biofilm. In this sense, the AFPFC were successfully used as a support for bacterial immobilization. Both systems, immobilized and suspended cells of P. putida F1, were able to completely degrade benzene and toluene from initial concentrations of 15, 30, 60, and 90 mg l−1. An inhibitory effect of the intermediary catechol from benzene degradation was observed in suspended cultures but it was not presented in the immobilized system. The degradation of o-xylene was partially accomplished in both systems. The Monod equation was used to model the experimental data obtained from the biodegradation kinetics, and they were adequately described with this model. 相似文献
4.
《Chemical Speciation and Bioavailability》2013,25(4):271-276
AbstractBiosorption is potentially an attractive technology for the treatment of wastewater by removing pesticide molecules from dilute solutions. This study investigated the feasibility of an isolated Bacillus sp. S14 immobilized in calcium alginate that was used as a biosorbent for Malathion removal from aqueous solutions in batch mode. The highest value of Malathion uptake by isolated Bacillus sp. S14 (1.33g L?1, dry basis) immobilized in 3% calcium alginate was 64.4% at 25°C and pH7.0 when the initial Malathion concentration was 50 mg L?1. Equilibrium was attained at 8h. The sorption data conformed well to the Fruendlich isotherm model. 相似文献
5.
Kevin Raymond Oluoch Ulrika Welander Maria Margareta Andersson Francis Jakim Mulaa Bo Mattiasson Rajni Hatti-Kaul 《Biocatalysis and Biotransformation》2006,24(3):215-222
Whole cells of Bacillus halodurans LBK 261 were used as a source of catalase for degradation of hydrogen peroxide. The organism, B. halodurans grown at 55°C and pH 10, yielded a maximum catalase activity of 275 U g-1 (wet wt.) cells. The catalase in the whole cells was active over a broad range of pH with a maximum at pH 8-9. The enzyme was optimally active at 55°C, but had low stability above 40°C. The whole cell biocatalyst exhibited a Km of 6.6 mM for H2O2 and Vmax of 707 mM H2O2 min-1 g-1 wet wt. cells, and showed saturation kinetics at 50 mM H2O2. The cells were entrapped in calcium alginate and used for H2O2 degradation at pH 9 in batch and continuous mode. In the batch process, the immobilized preparation containing 1.5 g (wet wt.) cells could be recycled at least four times for complete degradation of the peroxide in 50 mL solution at 25°C. An excess of immobilized biocatalyst could be used in a continuous stirred tank reactor for an average of 9 days at temperatures upto 55°C, and in a packed bed reactor (PBR) for 5 days before the beads started to deform. 相似文献
6.
The Bacillus sp. strain PHN 1 capable of degrading p-cresol was immobilized in various matrices namely, polyurethane foam (PUF), polyacrylamide, alginate and agar. The degradation
rates of 20 and 40 mM p-cresol by the freely suspended cells and immobilized cells in batches and semi-continuous with shaken cultures were compared.
The PUF-immobilized cells achieved higher degradation of 20 and 40 mM p-cresol than freely suspended cells and the cells immobilized in polyacrylamide, alginate and agar. The PUF- immobilized cells
could be reused for more than 35 cycles, without losing any degradation capacity and showed more tolerance to pH and temperature
changes than free cells. These results revealed that the immobilized cell systems are more efficient than freely suspended
cells for degradation of p-cresol. 相似文献
7.
《Chemical Speciation and Bioavailability》2013,25(3):207-213
AbstractThe removal of Malathion, a moderately toxic organophosphate pesticide causing environmental pollution, from dilute aqueous solutions was studied. The experimental results showed that the dry cells of Bacillus sp. S14 were effective in removing Malathion from solution. Biosorption equilibrium was attained within 6h. Maximum biosorption of Malathion (81.4%) was observed under the following environmental conditions, pH 6.5, temperature 25°C, dry biomass concentration 1g L?1 at 6h. Both Langmuir and Freundlich isotherms were tested and the latter had a better fit with the data. The dried powdered cells of Bacillus sp. S14 can be safely stored for 60 days at room temperature without any loss of biosorption efficiency. The results suggest that the dry cells of the isolated Bacillus sp. S14 can be used as a biosorbent for an efficient removal of Malathion from aqueous solutions. 相似文献
8.
Production of xylanases from a newly isolated alkalophilic thermophilic Bacillus sp. 总被引:4,自引:0,他引:4
A new thermophilic strain of Bacillus SPS-0 which produces thermostable xylanases was isolated from a hot spring in Portugal. Xylanase production was 50 nkat/ml in the presence of wheat bran arabinoxylan. The temperature and pH for optimum activity were 75°C and 6–9, respectively. The hydrolysis patterns demonstrated that crude xylanases yield mainly xylose and xylobiose from xylan, whereas xylose and arabinose were produced from destarched wheat bran. An increase in xylose release was observed when SPS-0 xylanase was supplemented by a ferulic acid esterase. © Rapid Science Ltd. 1998 相似文献
9.
Pamela S Fink Armando Soto G.Scott Jenkins Kathleen S Rupert 《FEMS microbiology letters》1997,153(2):387-392
A small RNA sequence identified in an rRNA-tRNA cluster from the thermophilic Bacillus sp. strain PS3 was examined. An oligonucleotide probe specific for the RNA bound to multiple restriction fragments in Bacillus sp. strain PS3 DNA, thus several copies of this sequence occur in its genome. Similar findings were observed using DNA from B. subtilis, B. stearothermophilus, Escherichia coli, Staphylococcus aureus, Haemophilus influenzae and Thermus thermophilus. This sequence apparently is widespread in the eubacteria. Northern analysis of RNA from sporulating Bacillus sp. strain PS3 and B. subtilis cells revealed RNA species homologous to the probe in both bacteria. Expression of the small RNA in B. subtilis depended on σH. 相似文献
10.
Anum Fareed Habiba Zaffar Azhar Rashid Muhammad Maroof Shah 《Bioremediation Journal》2017,21(3-4):119-127
A bacterial strain (TA7) capable of consuming three N-methylated carbamates as sole nitrogen and carbon source was isolated and identified as “Enterobacter cloacae” on the basis of 16S rRNA, from carbamate contaminated agricultural soil by enrichment culture technique. The agar entrapment was used to immobilize the bacterial cells. Both the free as well as the immobilized cells were used to study the degradation of three carbamets viz. aldicarb, carbofuran, and carbaryl. The immobilized cells degraded all the three carbamates much faster than their free cell counterparts. The biodegradation kinetics of aldicarb, carbaryl, and carbofuran was studied using 50 ppm as initial concentration in the presence of free cells. The average values of Ks for aldicarb, carbofuran, and carbaryl were 22.6, 17.87, and 8.9 mg/L, respectively, whereas the values for µmax were calculated as 1.35, 1.3, and 1.2 mg/l/h?1. The results indicated that the bacterium has high affinity towards all the three carbamates. However, relatively higher affinity is for carbaryl, in comparison with carbofuran and aldicarb. Results indicate the potential of E. Cloacae TA7 to remediate N-methylated carbamates polluted water and soil. 相似文献
11.
Bacillus sp. CSB39, isolated from popular traditional Korean food (Kimchi), produced a low molecular weight, thermostable mannanase (MnCSB39); 571.14 U/mL using locust bean gum galactomannan as a major substrate. It was purified to homogeneity using a simple and effective two-step purification strategy, Sepharose CL-6B and DEAE Sepharose Fast Flow, which resulted in 25.47% yield and 19.32-fold purity. The surfactant-, NaCl-, urea-, and protease-tolerant monomeric protein had a mass of ∼30 kDa as analyzed by SDS-PAGE and galactomannan zymography. MnCSB39 was found to have optimal activity at pH 7.5 and temperature of 70 °C. The enzyme showed ˃55% activity at 5.0–15% (w/v) NaCl, and ˃93% of the initial activity after incubation at 37 °C for 60 min. Trypsin and proteinase K had no effect on MnCBS39. The enzyme showed ˃80% activity in up to 3 M urea. The N-terminal amino acid sequence, ALKGDGX, did not show identity with reported mannanases, which suggests the novelty of our enzyme. Activation energy for galactomannan hydrolysis was 26.85 kJmol−1 with a Kcat of 142.58 × 104 s−1. MnCSB39 had Km and Vmax values of 0.082 mg/mL and 1099 ± 1.0 Umg−1, respectively. Thermodynamic parameters such as ΔH, ΔG, ΔS, Q10, ΔGE-S, and ΔGE-T supported the spontaneous formation of products and the high hydrolytic efficiency and feasibility of the enzymatic reaction, which strengthen its novelty. MnCSB39 activity was affected by metal ions, modulators, chelators, and detergents. Mannobiose was the principal end-product of hydrolysis. Bacillus subtilis CSB39 produced a maximum of 1524.44 U mannanase from solid state fermentation of 1 g wheat bran. MnCSB39 was simple to purify, was active at a wide pH and temperature range, multi-stress tolerant and catalyzes a thermodynamically possible reaction, characteristics that suggests its suitability for application as an industrial biocatalyst. 相似文献
12.
Minoru Shimura Gouri Mukerjee-Dhar Kazuhide Kimbara Hiroko Nagato Hohzoh Kiyohara Takashi Hatta 《FEMS microbiology letters》1999,178(1):87-93
Bacillus sp. strain JF8, which was isolated from compost, utilizes naphthalene and biphenyl as carbon sources at 60 degrees C. Biphenyl grown cells of strain JF8 barely degraded naphthalene while naphthalene grown cells did not degrade p-chlorobiphenyl, suggesting the existince of two independent degradation pathways. Isolation of JF8N, a mutant strain which can not utilize biphenyl as a carbon source while retaining the ability to utilize naphthalene, supports this hypothesis. Biphenyl grown cells of strain JF8 can degrade several polychlorinated biphenyl congeners including tetra- and pentachlorobiphenyl. bph and nah probes from mesophilic organisms failed to hybridize to strain JF8 DNA. 相似文献
13.
固定化硝化菌群联合芽孢杆菌处理对虾养殖废水 总被引:1,自引:1,他引:1
【背景】高度集约化的对虾养殖业面临着日益严重的水污染问题,同步高效降解养殖废水中的有机物、氨氮和亚硝酸盐是对虾养殖业健康可持续发展的重要保障之一。【目的】通过分别固定化硝化菌群(Nitrifyingbacterialconsortia,NBC)和芽孢杆菌,优化菌群空间结构,提高菌群功能,实现同步高效降解对虾养殖废水中的有机物、亚硝酸盐和氨氮,保障南美白对虾养殖的可持续发展。【方法】采集养殖虾塘底泥进行硝化细菌自养富集和连续培养,利用16S rRNA基因高通量测序技术分析硝化菌群组成。从5株芽孢杆菌中筛选化学需氧量(Chemical oxygen demand,COD)降解能力最强的菌株。选用吸附和成球效果好的无毒包埋材料,通过正交实验优化固定化配方提高机械强度。选择硝化菌群和芽孢杆菌最适使用浓度进行分别固定化并联合应用于对虾养殖废水的处理。【结果】高通量分析结果显示硝化菌群中变形菌门(Proteobacteria,61.10%)占绝对优势,具有自养硝化功能的类群丰度达12.69%并呈高多样性。还包含丰度达47.44%的具有反硝化功能或者潜在反硝化功能的优势菌群和丰度达12.85%的光合细菌,是高有机负荷下硝化作用的重要补充,并可通过反硝化作用实现真正脱氮。COD降解能力最强的是解淀粉芽孢杆菌(Bacillusamyloliquefacien)YL-10,48h内COD降解率达100%。固定化最佳配方为贝壳粉5%、海藻酸钠3%、交联剂氯化钙为4%、优化后的固定化小球其机械强度可达129.68m N。固定化使硝化菌群的氨氮和亚硝酸盐降解率分别提高了128.13%和130.11%(P0.05),但对芽孢杆菌YL-10的COD降解率无明显提高。1×10~8 CFU/mL为硝化菌群和芽孢杆菌YL-10在养殖废水中最适使用浓度。在固定化硝化菌群和芽孢杆菌YL-10联合作用下,对虾养殖废水的氨氮、亚硝酸盐和COD浓度在48h内分别由初始的6.32±0.12、5.69±0.11和65.29±1.14 mg/L降至0.03±0.03、0.06±0.01和0 mg/L (P0.05),降解率分别为99.57%、99.03%和100%。【结论】通过优化固定化有效提高硝化菌群的硝化作用,联合COD降解能力强的芽孢杆菌,同步高效降解对虾养殖废水中的有机物、氨氮和亚硝酸盐,为规模化应用于南美白对虾高密度养殖提供科学依据。 相似文献
14.
In the present study, cultivation of aerobic granular biomass capable of biodegradation of dibutyl phosphite, an organophosphite, and isolation of dibutyl phosphite degrading bacterial strains, are reported for the first time. The strain AMGD5, identified as Sphingobium sp., based on 16S rRNA sequencing, degraded dibutyl phosphite efficiently and utilised it as the sole source of carbon and phosphorus. Microbial degradation of dibutyl phosphite caused a significant decrease in medium pH, leading to cessation of growth and further degradation of dibutyl phosphite. Under buffered conditions, complete degradation of up to 3 mM of dibutyl phosphite was achieved within 60 h. The strain showed almost similar growth pattern when either phosphite or dibutyl phosphite was used as the phosphorous source. A 4-fold enhancement in phosphatase activity was evident in dibutyl phosphite fed cells, implying their role in dibutyl phosphite degradation. Sphingobium sp. AMGD5 can be a potential candidate for bioremediation of dibutyl phosphite contaminated waters or sites. 相似文献
15.
Singh Rajendra Pandey Deepak Devi Neena Chand Duni 《Bioprocess and biosystems engineering》2018,41(8):1225-1232
Bioprocess and Biosystems Engineering - Butyramide is a commodity chemical having wide range of applications from material science to biological sciences including synthesis of therapeutic drugs,... 相似文献
16.
Trimethyl lead degradation by free and immobilized cells of an Arthrobacter sp. and by the wood decay fungus Phaeolus schweinitzii 总被引:1,自引:0,他引:1
Summary The continuing production of leaded petrol generates liquid wastes containing recalcitrant trialkyl lead, for which no suitable chemical treatment has been formulated. This investigation explores the feasibility of using microorganisms to catalyse the rate-limiting step of trimethyl lead degradation to dialkyl lead; this disproportionates chemically to give, ultimately, Pb2+ which is treatable by classical methods. An Arthrobacter sp. and a wood decay macrofungus, Phaeolus schweinitzii provide novel evidence for metabolic trimethyl lead (Me3Pb+) degradation. The retention of this activity in immobilized cell column reactors challenged with Me3Pb+-supplemented flows suggests that a future biotreatment process may be possible.
Offprint requests to: M. E. Macaskie 相似文献
17.
Kim BK Chung JH Kim SY Jeong H Kang SG Kwon SK Lee CH Song JY Yu DS Ryu CM Kim JF 《Journal of bacteriology》2012,194(14):3758-3759
Plant growth-promoting bacteria colonize various habitats, including the phyllosphere. Here, we present the high-quality draft genome sequence of Bacillus sp. strain 5B6, which was isolated from the leaf of a cherry tree. The 3.9-Mb genome uncovers its potential for understanding the nature of leaf colonization as well as antibiosis against plant pathogens. 相似文献
18.
The properties of the ATPase in the facultative thermophile, Bacillus coagulans, grown at thermophilic or mesophilic temperatures were similar. Arrhenius plots did not show discontinuities indicative of thermoadaptation. Magnesium stimulation of the enzyme was dependant on the assay temperature but independant of the growth temperature. The ATPase in cells grown at 35°C or 55°C was equally thermostable at 65°C. In contrast, the ATPase from the mesophile, Bacillus megaterium (T
max=42°C) was completely inactivated at 55°C in 5 min. 相似文献
19.
A. Sharma C. L. S. N. Rao B. K. Ball S. K. Hasija 《World journal of microbiology & biotechnology》1996,12(6):615-617
Forty bacterial isolates from the effluents of a gelatin factory (Jabalpur, India) were screened for protease activity and the two most potent producers were identified as Bacillus laterosporus and a Flavobacterium sp. The enzymes of both isolates were optimal at pH 8 and 60°C, with maximum activity after 90 min. The enzyme activity of B. laterosporus was suppressed by Fe2+, Mg2+, Mn2+ and Zn2+ ions but was enhanced by Ba2+ and Ca2+. That of Flavobacterium sp. was suppressed by Mg2+ and Mn2+ ions but enhanced by Ba2+, Ca2+ and Fe2+. The enzyme activity of the former was strongly inhibited by KCN, whereas that of the latter was only slightly inhibited by 8-hydroxyquinoline. 相似文献
20.
Conversion of sodium cyanide to carbon dioxide and ammonia by immobilized cells ofPseudomonas putida
G. R. V. Babu James H. Wolfram Kirit D. Chapatwala 《Journal of industrial microbiology & biotechnology》1992,9(3-4):235-238
Summary
Pseudomonas putida, isolated from contaminated industrial wastewaters and soil sites, was found to utilize sodium cyanide (NaCN) as a sole source of carbon and nitrogen. Cells, immobilized in calcium alginate beads (1–2 mm diameter) were aerated in air-uplift-type fluidized batch bioreactor containing 100–400 ppm of NaCN. Degradation of NaCN was monitored for 168 h by analyzing gaseous and dissolved ammonia (NH3), CO2, pH and optical density. The results indicated that the alginate-immobilized cells ofP. putida were able to degrade NaCN into NH3 and CO2 in a time-dependent manner. 相似文献