共查询到20条相似文献，搜索用时 15 毫秒
1.
Chung SH Kim IH Park HG Kang HS Yoon CS Jeong HY Choi NJ Kwon EG Kim YJ 《Journal of agricultural and food chemistry》2008,56(9):3311-3316
This study was performed to discover bifidobacteria isolated from human intestines that optimally convert linoleic acid (LA) to conjugated linoleic acid (CLA) and to optimize the culture conditions of milk fermentation. One hundred and fifty neonatal bifidobacteria were screened for CLA-producing ability, and Bifidobacterium breve LMC 017 was selected as it showed about 90% conversion of free LA in MRS broth. The selected strain showed resistance at 0.5% LA in microaerophillic conditions. When monolinolein (LA 90%) was used as a substrate for CLA production, the conversion rate was lower compared to free LA, but the growth rate was unaffected during the milk fermentation. There was no significant difference in CLA production between aerobic and anaerobic conditions, and little decline in CLA was shown after the maximal CLA level had been reached. CLA production increased by 80% with 24 h of incubation in milk containing additional skim milk (5%), where the proteins may have facilitated the production of CLA by enhancing the interaction of substrate with the bacteria. CLA production did not decline after 9 h of fermentation and an additional 12 weeks of storage with other commercial starters. This demonstrates the possibility of using this strain as a costarter in the production of CLA-enriched yogurt. 相似文献
2.
Achromobacter piechaudii strain TBPZ is a 2,4,6-tribromophenol (TBP) degrader that was isolated from contaminated desert soil. In the current study we have found that yeast extract has a substantial impact on the debromination activity of non-dividing cells of TBPZ harvested during the stationary phase. The results suggest that yeast extract provides a factor that is necessary for activity and that is missing in stationary cells. Nevertheless, strain TBPZ from the stationary phase did survive and degrade TBP in soils with different degrees of contamination without yeast extract supplements. Experiments with soil extracts showed that a soluble factors is responsible for this phenomenon in a similar way to yeast extract. To test whether other soil bacteria provide these factors, co-culture experiments with strain TBPZ and a bisphenol A (BPA) degrader, Sphingomonas strain WH1, that was isolated from the same contaminated desert soil, were carried out. These experiments clearly demonstrated that growth of strain WH1 on BPA enables strain TBPZ to degrade TBP rapidly, suggesting that a metabolic product from WH1 is involved. In experiments with mixed amino acid blend (casamino acid), slower growth was observed when compared to growth with yeast extract. Providing vitamins and a defined mixture of two amino acids, tryptophan and phenylalanie, caused rapid degradation of TBP without the rapid growth seen in yeast extract treatment, indicating that the amino acids are needed to sustain biodegradation activity. The results of this study highlight that degradation of TBP by strain TBPZ is possibly controlled by micronutrients. In addition, the results suggest that an auxotrophic bacterium able to degrade halo-organic pollutants can survive in a natural environment due to its interaction with natural organic matter or other microorganisms. 相似文献
3.
Park HG Heo W Kim SB Kim HS Bae GS Chung SH Seo HC Kim YJ 《Journal of agricultural and food chemistry》2011,59(3):984-988
This study was performed to characterize the ability of an active Bifidobacterium strain to produce conjugated linoleic acid (CLA) and to test its possible utilization as a probiotic compatible to the ruminal condition. Bifidobacterium breve LMC520 can actively convert linoleic acid (LA) to cis-9,trans-11-CLA, which is a major isomer derived from microbial conversion. LMC520 showed reasonable tolerance under acidic conditions (pH 2.5 with 1% pepsin) and in the presence of oxgall (0-3%). The growth and CLA production of LMC520 were tested under ruminal conditions and compared with those of Butyrivibrio fibrisolvens A38, which is a major CLA producer in the rumen as an intermediate in the biohydrogenation (BH) process. LMC520 converted 15% of LA to CLA under ruminal conditions, which was 2 times higher activity than that of A38, and there was no decline in CLA level during prolonged incubation of 48 h. The BH activity of LMC520 was comparable to that of A38. When LMC520 was cocultured with A38, even with slight decrease of CLA due to high BH activity by A38, but the level of CLA was maintained by the high CLA-producing activity of LMC520. This comparative study shows the potential of this strain to be applied as a functional probiotic not only for humans but also for ruminants as well as to increase CLA production. 相似文献
4.
Liu Yang Shaohua Chen Meiying Hu Weining Hao Peng Geng Yanbo Zhang 《Biology and Fertility of Soils》2011,47(8):917-923
A novel yeast named HQ-C-01 was isolated from activated sludge and identified as Pichia anomala based on the morphology and 18S rDNA sequence analysis. The HQ-C-01 strain degraded 95.2% of carbofuran when the insecticide
was used as the only C source and added at 50 mg/L in a mineral salts medium within 48 h. The optimal concentration, temperature,
and pH of medium for degradation of carbofuran were 50 mg/L, 30°C, and pH 7.5, respectively. Strain HQ-C-01 could also effectively
degrade other carbamate insecticides including carbaryl, indoxacarb, and fenobucarb, and the degradation rates were 99%, 85%,
and 67%, respectively. Gas chromatography–mass spectrometry analysis showed that the strain metabolized carbofuran to produce
benzofuranol as the intermediate metabolite, which was further degraded. Degradation of carbofuran added at 50 mg/kg of soil
was higher in yeast-inoculated soil than in the control. These results indicated that strain HQ-C-01 may potentially be used
in bioremediation of carbofuran-contaminated soil. 相似文献
5.
Darya O. Egorova Sergei A. Buzmakov Elmira A. Nazarova Dmitryi N. Andreev Vitaly A. Demakov Elena G. Plotnikova 《Water, air, and soil pollution》2017,228(5):183
Currently, there are large areas of soils contaminated with hexachlorocyclohexane (HCH) isomers which are included in the group of persistent organic pollutants. For the bioremediation of such soils, a new HCH-degrading Rhodococcus wratislaviensis strain Ch628 was isolated from long-term organochlorine contaminated soils. The strain Ch628 was able to degrade 32.3% γ-hexachlorocyclohexane (γ-HCH/lindane), 25.2% hexachlorobenzene, and 100% chlorobenzene in resting cell conditions. The strain Ch628 was bioaugmented in chronically HCH-contaminated soil. The results showed that the bioaugmentation of contaminated soil with the strain Ch628 led to HCH degradation. In the bioaugmented system, the efficiency of HCH removal at the initial concentration of about 238.7 ± 4.9 mg kg?1 soil was 44.8%, while the system with indigenous microflora (without R. wratislaviensis strain Ch628) and the system with abiotic control removed 33.3 and 16.4% of this compound during the same period, respectively. Strain Ch628 could effectively degrade α-, β-, and γ-isomers of HCH (77.1, 100, and 100%, respectively) and heptachlorocyclohexane (69.9%) in the model soil systems. Moreover, the bioaugmentation with the strain Ch628 led to degradation of tri-, tetra-, and penta-chlorobenzenes, which are of HCH degradation metabolites. For the first time, it was found that the bioaugmentation with the bacterial strain Rhodococcus wratislaviensis Сh628 led to a significant reduction of the toxicity of the HCH-contaminated soil for the test organisms, such as Chlorella vulgaris Beijer and Daphnia magna Straus. 相似文献
6.
Tian Li Xin-Ping Deng Jin-Jun Wang Hui Zhao Lei Wang Kun Qian 《Water, air, and soil pollution》2012,223(6):3271-3279
A Gram-negative bacterium strain LWD09, capable of growing aerobically on 3,4-dichloroaniline (DCA) as the sole carbon and energy source, was isolated from the farm field. This bacterium was identified as Myroides odoratimimus strain by morphological, physiological, and biochemical characteristics as well as 16S rDNA sequence. Analysis of culture pH, temperature, cells growth, and DCA concentration demonstrated that strain LWD09 could effectively degrade DCA without a lag phase. The kinetics of DCA degradation was well described using the Andrews equation, and the kinetic parameters were as follows: q max?=?1.74?h?1, K s?=?43.5?mg?L?1, and K i?=?230.3?mg?L?1. In addition, strain LWD09 was found to be moderately halophilic and showed the highest power of DCA degradation in 5% NaCl (w/w, %). With initial concentrations of 30, 100, and 200?mg?L?1, 100%, 80.4%, and 33.2% of DCA were transformed after 96?h in 5% NaCl, respectively. These results suggest that strain LWD09 has the potential to degrade DCA in saline wastewater. To date, this is the first report on the degradation of DCA by a M. odoratimimus strain with moderate salinity tolerance. 相似文献
7.
Edward Topp 《Biology and Fertility of Soils》2001,33(6):529-534
The ability of three atrazine-degrading bacteria, Pseudomonas sp. strain ADP, a Pseudaminobacter sp., and a Nocardioides sp., to degrade and mineralize this herbicide in a loam soil was evaluated in laboratory microcosms. These bacteria all hydrolytically dechlorinate atrazine, and degrade atrazine in pure culture with comparable specific activities. The Pseudaminobacter and Nocardioides can utilize atrazine as sole carbon and nitrogen source, whereas the Pseudomonas can utilize the compound only as a nitrogen source. The Pseudomonas and Pseudaminobacter mineralize the compound; the end product of atrazine metabolism by the Nocardioides is N-ethylammelide. At inoculum densities of 105 cells/g soil, only the Pseudaminobacter and Nocardioides accelerated atrazine dissipation. The Pseudaminobacter mineralized atrazine rapidly and without a lag, whereas atrazine was mineralized in the Nocardioides-inoculated soil but only after a lag of several days. The Pseudaminobacter remained viable longer than did the Pseudomonas in soil. PCR analysis of recovered bacteria indicated that the genes atzA (atrazine chlorohydrolase) and atzB (hydroxyatrazine ethylaminohydrolase) were less stable in the Pseudaminobacter than the Pseudomonas. In summary, this study has revealed important differences in the ability of atrazine-hydrolyzing bacteria to degrade this compound in soil, and suggests that the ability to utilize atrazine as a carbon source is important to establish "enhanced degradation" by ecologically meaningful inoculum densities. 相似文献
8.
从活性污泥的富集培养物中分离得到可降解几种拟除虫菊酯农药的菌株qw5,初步鉴定qw5为地衣芽孢杆菌 (Bacilliuslicheniformis)。菌株qw5在通气、pH7～ 8、温度 3 0℃左右的环境条件下生长较好。培养 5天 ,菌株qw5对氰戊菊酯、氯氰菊酯、溴氰菊酯的降解率分别为 5 3 .8%、41 .2 %和 61 .7%。经质谱分析 ,菌株qw5降解氰戊菊酯产生中间代谢产物 3 -苯氧基苯甲醛。qw5对小白鼠无致病力 ,对几种常用的抗生素敏感。盆钵和小区试验表明 ,菌株qw5对青菜中残留的拟除虫菊酯有明显去除效果。 相似文献
9.
以太湖水华蓝藻中提取纯化的微囊藻毒素（microcystins,MCs）作为微生物生长的碳源和氮源,从富营养化的太湖水体中分离筛选到MCs高效降解菌群JSM004,24h内可以将初始浓度分别为3．64和2．62mg·L^-1的MC—RR和MC—LR完全降解。在研究关于环境因子对JSM004降解效率的影响中,发现菌群JSM004的生长受温度和pH值影响较大,而且其对MCs的降解效率也随之变化。结果表明,在接近实际水体的中性和弱碱性环境中,JSM004对MCs的降解活性最强,加入不同含碳和含氮化合物能够促进混合微生物菌群的生长,但是对MCs的降解却有明显的延滞作用。与对照组相比,MCs被完全降解的时间至少推迟24h。在实验室条件下,JSM004可在72h内完全降解太湖水中高浓度的MCs。研究结果表明微囊藻毒素降解菌群JSM004具有良好的MCs降解效果,有实际应用前景。 相似文献
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Organic debris extracted from wheatfield soils was found to be significantly more infective following 2–3 yr continuous wheat than after the fifth successive crop. Plots with added nitrogen yielded more infective debris than those without. Short periods of contact with decline soil or its suspension, reduced infection of wheat roots by Gaeumannomyces when they were subsequently grown in non-decline soil. Hyphae emerging from previously infected root pieces or culture inocula showed a positive growth response to wheat roots or their exudates. This response was negatively correlated to the distance between root and inoculum. In the presence of decline soil, hyphal response was significantly reduced. This reduction can be related to the decreased infectivity of decline soil and may help to explain take-all decline. 相似文献
12.
Erika A. Wolski Ignacio Durruty Patricia M. Haure Jorge F. González 《Water, air, and soil pollution》2012,223(5):2323-2332
Phenol is a typical contaminant of the environment generated by many industries. Several fungi had been reported to degrade phenol as the only source of carbon and energy, but many of them are not useful to apply in soil bioremediation process. In this work, we study the dynamics of phenol degradation by a Penicillium chrysogenum, isolated from soil. Degradation of phenol was studied at room temperature and resting mycelium conditions. High specific degradation rates were obtained. Inhibition was observed on the specific growth rate (30?mg?l1) and the degradation rate (200?mg?l?1). Experimental results were fitted to several models during exponential phase, with the Andrews-Haldane model given the best fit. Dynamic mass balance equations for biomass and phenol during the exponential and stationary growth phases were solved and compared very satisfactorily to experimental outcomes. P. chrysogenum degrades phenol completely during the exponential and stationary growth phases. The results obtained are relevant for its practical applications in soil decontamination processes. Model predictions were satisfactory. This is the first work which describes a kinetic model for phenol biodegradation using a filamentous fungus considering both, exponential and stationary phases, and the first one in which a Penicillium isolate is used. 相似文献
13.
从4个草鱼池塘中分离和定性筛选获得29株能够产生氨氮和亚硝酸盐氮的菌株。通过对编号为C95的菌株进行菌落形态学观察和16S rDNA序列分析,表明该菌株为革兰氏阴性杆状菌,与寡养单胞菌属（Stenotrophomonas sp.）的同源性达98%。采用单因素多水平试验对菌株的产氨氮和产亚硝酸盐氮特性进行研究发现：（1）氮源、碳源、温度和摇床转速都能显著影响菌株的生长及产生氨氮和亚硝酸盐氮的含量,但pH（5～9）对其无显著影响（P〉0.05）;（2）该菌株生长及产生氨氮和亚硝酸盐氮最适宜的培养基以及培养条件为：LB、pH 5～9、25℃、150 r.min-1。由C95作为指示菌株筛选得到SC01、SC07两株（2/33）去除氨氮和亚硝酸盐氮效果较好的菌株。因此,C95可作为筛选具有降氨氮和亚硝酸盐氮功能的有益菌的指示菌株。 相似文献
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Giuseppe Bonanno 《Water, air, and soil pollution》2014,225(2):1-8
Iopromide has been frequently detected in different environmental compartments. However, the biodegradation of iopromide was limited, and significantly different removal efficiencies by various methods were reported. In this study, a Pseudomonas sp. I-24 isolated from activated sludge in a sewage treatment plant was used to degrade iopromide. Four different cosubstrates were selected as the cometabolic carbon and energy sources. The results showed that cosubstrate starch was able to increase catabolic enzymatic activity and enhance iopromide degradation. The degradation efficiency of iopromide was as high as 88.24 %, which was much higher as compared with other cosubstrates (38.58–51.44 %) and blank sample (2.81 %). Additionally, the highest enzymatic activity of 0.182 mU for iopromide degradation was also obtained when adding starch as a cosubstrate, somehow supporting that higher enzymatic activity resulted in higher degradation efficiency for iopromide. Although little was illuminated about the molecular mechanism during the degradation process of iopromide with starch addition, the two-dimensional gel electrophoresis results indicated that the iopromide-degrading cells growing with cosubstrate starch underwent significant physiological changes. 相似文献
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《Applied soil ecology》1999,11(1):79-90
Escherichia coli K12 strain (J5-3/RP4) persisted in sandy loam for more than 70 days when incubated at 10°C or 4°C. It decreased to below the level of detection within 20 days when incubated at 25°C. No loss of multi-resistance plasmid RP4 from the E. coli cells was detected during incubation in soil. There was a positive relation between the bacterial inoculum size and the following increase of the protozoan numbers in the soil. When soil microcosms were amended with an eukaryotic inhibitor, the period of survival was increased. These observations indicate a direct involvement of protozoa in the decline of E. coli in soil. Transfer of plasmid RP4 from E. coli donor bacteria to indigenous bacteria in soil was detected already 24 h after addition of the E. coli K12 donor strain. The efficiency of transfer during the first 48 h was approximately 10−6 transconjugants per donor. Inhibition of protozoan predation increased the number of transconjugants appearing in the soil, but the transfer efficiency per donor was not affected by the decreased predation. No transfer could be detected when the donor strain was washed and resuspended in saline before addition to the soil, but transconjugants were detected in this experiment when nutrients (LB) were supplemented after two days of incubation. Plasmid RP4 was maintained in the transconjugant soil bacteria throughout the experiment. The data presented here indicate that the indigenous bacteria in soil may serve as a sink for plasmidborne traits. 相似文献
18.
Craita Maria Rosu Mihaela Avadanei Daniela Gherghel Marius Mihasan Cosmin Mihai Adriana Trifan Anca Miron Gabriela Vochita 《Water, air, and soil pollution》2018,229(1):15
In consideration of the hazards associated with the presence of the textile azo-dye and their biotransformation products in the environment, the goal of this work was to study bioremediation process by the yeast strain Pichia kudriavzevii CR-Y103 related to the ability to degrade and detoxify the sulfonated Reactive Orange 16 azo-dye. In experimental conditions, the optimal inoculum/dye concentration ratio required for complete decolorization (100%) of culture medium and biomass within 24 h has been 1 g L?1 yeast cell (dry weight)/50 mg L?1 Reactive Orange 16. In the presence of 400 mg L?1 of Reactive Orange 16 (RO16), 95% of the dye was removed after 72 h of incubation. Also, the yeast strain could decolorize other eight textile dyes (56.48–99.98% decolorization within 24 h). NADH-DCIP reductase and azo reductase activities were significantly increased (ca. 5.4 times and ca. 37 times, respectively) during the decolorization process. UV-VIS spectra, high-performance liquid chromatography (HPLC), and Fourier transform infrared spectroscopy (FTIR) analysis confirmed the presence of new biotransformation products in extracted metabolites, highlighting the partial biodegradation of the dye by the new yeast isolate. The phytotoxicity evaluation strongly supported the decreased toxicity of biodegraded products as minor inhibition on germination (%), root and shoots elongation of T. pratense L. and T. aestivum L. seedlings. Increasing of mitotic index value and decreasing the frequency of chromosomal aberrations in tested plant meristem cells treated with biodegraded products, compared with RO16 treatment (500 ppm), confirmed their slightly toxic nature. A cell viability assay also confirmed the reduced toxicity of biodegraded products on healthy monkey kidney cells (Vero cells). 相似文献
19.
ZHANG Man-Yun TENG Ying ZHU Ye WANG Jun LUO Yong-Ming P. CHRISTIE LI Zhen-Gao T. K. UDEIGWE 《土壤圈》2014,24(6):799-807
A chlorothalonil(CTN)-degrading bacterial strain H4 was isolated in this study from a contaminated soil by continuous enrichment culture to identify its characteristics and to investigate its potential for remediation of CTN in contaminated soil. Based on the morphological, physiological and biochemical tests and 16 S r DNA sequence analysis, the strain was identified as Stenotrophomonas sp. After liquid culture for 7 d, 82.2% of CTN was removed by strain H4. The isolate could degrade CTN over a broad range of temperatures and p H values, and the optimum conditions for H4 degradation were p H 7.0 and 30℃. Reintroduction of the bacteria into artificially contaminated soil resulted in substantial removal of CTN( 50%) after incubation for 14 d. Soil samples treated by H4 showed significant increases(P 0.05) in soil dehydrogenase activity, soil polyphenol oxidase activity, average well-color development obtained by the Biolog Eco plate TM assay and Shannon-Weaver index, compared with the control. Strain H4 might be a promising candidate for application in the bioremediation of CTN-contaminated soils. 相似文献
20.
Partial inhibition of biohydrogenation of linoleic acid can increase the conjugated linoleic acid production of Butyrivibrio fibrisolvens A38 总被引：1，自引：0，他引：1
Kim YJ 《Journal of agricultural and food chemistry》2003,51(15):4258-4262
Butyrivibrio fibrisolvens A38, one of the most active rumen bacteria in conjugated linoleic acid (CLA) production, was characterized in vitro. Previous findings that some inhibitory levels of substrate for biohydrogenation (BH) by B. fibrisolvens A38 resulted in more CLA accumulation led to a prediction that partial inhibition of BH could increase ruminal CLA production. The inhibitory conditions for bacterial growth were less effective on the isomerization step than on the following reduction step. Linoleic acid (LA) was inhibitory not only to cell growth but also to LA hydrogenation, and this effect was greater at high concentrations. The reduction step, converting CLA to hydrogenated products (trans-C18:1 and C18:0), was significantly inhibited, and more CLA accumulated during aerobic incubation when LA was added along with a glycolytic inhibitor, iodoacetate (IAA), to cells that were pre-adapted to LA (1 g/OD at 600 nm/L, P < 0.05). Monensin was more inhibitory than IAA to cell growth but less effective for CLA accumulation. Rumen fluid in the culture medium appeared to activate BH even in an aerobic condition, resulting in a lower CLA level than the control group (P < 0.05). Because the isomerization and reduction steps are coupled reactions in BH of most hydrogenating bacteria including B. fibrisolvens A38 cells, both positive and negative modulations of the reduction steps could be key determinants for CLA accumulation in the rumen. 相似文献