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1.
Braz. j. microbiol ; 49(2): 258-268, Apr.-June 2018. graf
Article in English | LILACS | ID: biblio-889233

ABSTRACT

Abstract Cellulosimicrobium cellulans CWS2, a novel strain capable of utilizing benzo(a)pyrene (BaP) as the sole carbon and energy source under nitrate-reducing conditions, was isolated from PAH-contaminated soil. Temperature and pH significantly affected BaP biodegradation, and the strain exhibited enhanced biodegradation ability at temperatures above 30 °C and between pH 7 and 10. The highest BaP removal rate (78.8%) was observed in 13 days when the initial BaP concentration was 10 mg/L, and the strain degraded BaP at constant rate even at a higher concentration (50 mg/L). Metal exposure experimental results illustrated that Cd(II) was the only metal ion that significantly inhibited biodegradation of BaP. The addition of 0.5 and 1.0 g/L glucose enhanced BaP biodegradation, while the addition of low-molecular-weight organic acids with stronger acidity reduced BaP removal rates during co-metabolic biodegradation. The addition of phenanthrene and pyrene, which were degraded to some extent by the strain, showed no distinct effect on BaP biodegradation. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the five rings of BaP opened, producing compounds with one to four rings which were more bioavailable. Thus, the strain exhibited strong BaP degradation capability and has great potential in the remediation of BaP-/PAH-contaminated environments.


Subject(s)
Soil Microbiology , Soil Pollutants/metabolism , Benzo(a)pyrene/metabolism , Actinobacteria/isolation & purification , Actinobacteria/metabolism , Temperature , Cadmium/metabolism , Carbon/metabolism , Carboxylic Acids/metabolism , Biotransformation , Actinobacteria/classification , Culture Media/chemistry , Enzyme Inhibitors/metabolism , Glucose/metabolism , Hydrogen-Ion Concentration , Anaerobiosis , Gas Chromatography-Mass Spectrometry
2.
Braz. j. microbiol ; 46(2): 367-375, Apr-Jun/2015. tab, graf
Article in English | LILACS | ID: lil-749711

ABSTRACT

The pH of the culture medium directly influences the growth of microorganisms and the chemical processes that they perform. The aim of this study was to assess the influence of the initial pH of the culture medium on the production of 11 low-molecular-weight organic acids and on the solubilization of calcium phosphate by bacteria in growth medium (NBRIP). The following strains isolated from cowpea nodules were studied: UFLA03-08 (Rhizobium tropici), UFLA03-09 (Acinetobacter sp.), UFLA03-10 (Paenibacillus kribbensis), UFLA03-106 (Paenibacillus kribbensis) and UFLA03-116 (Paenibacillus sp.). The strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 solubilized Ca3(PO4)2 in liquid medium regardless of the initial pH, although without a significant difference between the treatments. The production of organic acids by these strains was assessed for all of the initial pH values investigated, and differences between the treatments were observed. Strains UFLA03-09 and UFLA03-10 produced the same acids at different initial pH values in the culture medium. There was no correlation between phosphorus solubilized from Ca3(PO4)2 in NBRIP liquid medium and the concentration of total organic acids at the different initial pH values. Therefore, the initial pH of the culture medium influences the production of organic acids by the strains UFLA03-08, UFLA03-09, UFLA03-10 and UFLA03-106 but it does not affect calcium phosphate solubilization.


Subject(s)
Acinetobacter/metabolism , Carboxylic Acids/metabolism , Culture Media/chemistry , Paenibacillus/metabolism , Phosphates/metabolism , Rhizobium tropici/metabolism , Acinetobacter/growth & development , Acinetobacter/isolation & purification , Fabaceae/microbiology , Hydrogen-Ion Concentration , Paenibacillus/growth & development , Paenibacillus/isolation & purification , Rhizobium tropici/growth & development , Rhizobium tropici/isolation & purification , Root Nodules, Plant/microbiology
3.
Biol. Res ; 48: 1-8, 2015. ilus, graf, tab
Article in English | LILACS | ID: biblio-950788

ABSTRACT

BACKGROUND: The development of clean or novel alternative energy has become a global trend that will shape the future of energy. In the present study, 3 microbial strains with different oxygen requirements, including Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, were used to construct a hydrogen production system that was composed of a mixed aerobic-facultative anaerobic-anaerobic consortium. The effects of metal ions, organic acids and carbohydrate substrates on this system were analyzed and compared using electrochemical and kinetic assays. It was then tested using small-scale experiments to evaluate its ability to convert starch in 5 L of organic wastewater into hydrogen. For the one-step biohydrogen production experiment, H1 medium (nutrient broth and potato dextrose broth) was mixed directly with GAM broth to generate H2 medium (H1 medium and GAM broth). Finally, Clostridium acetobutylicum ATCC 824, Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D of three species microbial co-culture to produce hydrogen under anaerobic conditions. For the two-step biohydrogen production experiment, the H1 medium, after cultured the microbial strains Enterobacter cloacae ATCC 13047 and Kluyveromyces marxianus 15D, was centrifuged to remove the microbial cells and then mixed with GAM broth (H2 medium). Afterward, the bacterial strain Clostridium acetobutylicum ATCC 824 was inoculated into the H2 medium to produce hydrogen by anaerobic fermentation. RESULTS: The experimental results demonstrated that the optimum conditions for the small-scale fermentative hydrogen production system were at pH 7.0, 35°C, a mixed medium, including H1 medium and H2 medium with 0.50 mol/L ferrous chloride, 0.50 mol/L magnesium sulfate, 0.50 mol/L potassium chloride, 1% w/v citric acid, 5% w/v fructose and 5% w/v glucose. The overall hydrogen production efficiency in the shake flask fermentation group was 33.7 mL/h-1.L-1, and those the two-step and the one-step processes of the small-scale fermentative hydrogen production system were 41.2 mLVh-1.L-1 and 35.1 mL/h-1.L-1, respectively. CONCLUSION: Therefore, the results indicate that the hydrogen production efficiency of the two-step process is higher than that of the one-step process.


Subject(s)
Fermentation/physiology , Microbial Consortia/physiology , Hydrogen/metabolism , Industrial Waste , Starch/metabolism , Time Factors , Kluyveromyces/metabolism , Carboxylic Acids/metabolism , Feasibility Studies , Enterobacter cloacae/metabolism , Coculture Techniques , Clostridium acetobutylicum/metabolism , Electric Conductivity , Microbial Interactions/physiology , Renewable Energy , Waste Water/analysis , Hydrogen/analysis , Ions/metabolism , Metals/metabolism
4.
Braz. j. microbiol ; 45(3): 937-943, July-Sept. 2014. graf, tab
Article in English | LILACS | ID: lil-727024

ABSTRACT

Strain P17 was a bacterial strain identified as Bacillus megaterium isolated from ground accumulating phosphate rock powder. The fermentation broth of strain P17 and the yellow-brown soil from Nanjing Agricultural University garden were collected to conduct this study. The simulation of fixed insoluble phosphorous forms after applying calcium superphosphate into yellow-brown soil was performed in pots, while available P and total P of soil were extremely positive correlative with those of groundwater. Then the dissolving effect of strain P17 on insoluble P of yellow-brown soil was studied. Results showed that Bacillus megaterium strain P17 had notable solubilizing effect on insoluble phosphates formed when too much water-soluble phosphorous fertilizer used. During 100 days after inoculation, strain P17 was dominant. Until the 120th day, compared with water addition, available P of strain P17 inoculation treated soil increased by 3 times with calcium superphosphate addition. Besides available P, pH, activity of acid and alkaline phosphatase and population of P-solubilizing microbes were detected respectively. P-solubilizing mechanism of P-solubilizing bacteria strain P17 seems to be a synergetic effect of pH decrease, organic acids, phosphatase, etc.


Subject(s)
Bacillus megaterium/metabolism , Calcium Phosphates/metabolism , Phosphorus/metabolism , Soil/chemistry , Bacillus megaterium/isolation & purification , Carboxylic Acids/metabolism , Hydrogen-Ion Concentration , Phosphoric Monoester Hydrolases/metabolism , Soil Microbiology
5.
Braz. j. microbiol ; 44(4): 1121-1131, Oct.-Dec. 2013. ilus, graf, tab
Article in English | LILACS | ID: lil-705292

ABSTRACT

Among the native yeasts found in alcoholic fermentation, rough colonies associated with pseudohyphal morphology belonging to the species Saccharomyces cerevisiae are very common and undesirable during the process. The aim of this work was to perform morphological and physiological characterisations of S. cerevisiae strains that exhibited rough and smooth colonies in an attempt to identify alternatives that could contribute to the management of rough colony yeasts in alcoholic fermentation. Characterisation tests for invasiveness in Agar medium, killer activity, flocculation and fermentative capacity were performed on 22 strains (11 rough and 11 smooth colonies). The effects of acid treatment at different pH values on the growth of two strains ("52" -rough and "PE-02" smooth) as well as batch fermentation tests with cell recycling and acid treatment of the cells were also evaluated. Invasiveness in YPD Agar medium occurred at low frequency; ten of eleven rough yeasts exhibited flocculation; none of the strains showed killer activity; and the rough strains presented lower and slower fermentative capacities compared to the smooth strains in a 48-h cycle in a batch system with sugar cane juice. The growth of the rough strain was severely affected by the acid treatment at pH values of 1.0 and 1.5; however, the growth of the smooth strain was not affected. The fermentative efficiency in mixed fermentation (smooth and rough strains in the same cell mass proportion) did not differ from the efficiency obtained with the smooth strain alone, most likely because the acid treatment was conducted at pH 1.5 in a batch cell-recycle test. A fermentative efficiency as low as 60% was observed with the rough colony alone.


Subject(s)
Alcohols/metabolism , Saccharomyces cerevisiae/growth & development , Saccharomyces cerevisiae/metabolism , Carboxylic Acids/metabolism , Culture Media/chemistry , Fermentation , Hydrogen-Ion Concentration , Saccharomyces cerevisiae/drug effects
6.
Article in English | IMSEAR | ID: sea-163307

ABSTRACT

The matrix metalloproteinase-13 (MMP-13) inhibitory activities of carboxylic acid based compounds, in presence and absence of bovine serum albumin (BSA), have been analyzed quantitatively in terms of chemometric descriptors. The statistically validated quantitative structure-activity relationship (QSAR) models obtained through combinatorial protocol in multiple linear regression (CP-MLR) analysis and the participated descriptors in these models provided rationales to explain the inhibitory activities of these congeners. For MMP-13 inhibition activity, the identified descriptors (BEHm1, BELm1 and BEHm8) have highlighted the role of the atomic mass in terms of the highest and lowest eigenvalues derived from Burden matrix. The positive correlation with activity suggested that their higher values are desirable in improving the activity of a compound. Additionally, the descriptor C-027 representing R-CH-X type fragment in a molecular structure advocates the absence of such type of fragment for the improved activity. On the other hand presence of RCO-N< or >N-X=X type fragment (descriptor N-072) would be beneficiary to the MMP-13 inhibitory activity. The structural features, rationalized by the descriptors MSD (Balaban’s mean square distance index), nCrHR (number of ring tertiary C (sp3), H-047 (H attached to C1(sp3)/C0(sp2)) and H-050 (H attached to heteroatom) have imparted positive impact on the MMP-13 w/BSA inhibition activity. The atomic properties such as atomic polarizability and atomic Sanderson’s electronegativity have shown their positive impact on the activity via descriptors BELp4 and GATS3e in respective eigenvalues or lag. The other descriptors, MATS1m and MATS3e, have revealed the negative influence of atomic mass and electronegativity on the of MMP-13 w/BSA inhibition activity. The results obtained from CP-MLR analysis have been supported further through partial least-squares (PLS) study.


Subject(s)
Carboxylic Acids/analogs & derivatives , Carboxylic Acids/analysis , Carboxylic Acids/metabolism , Enzyme Inhibitors/chemistry , Linear Models , Matrix Metalloproteinase Inhibitors/analysis , Matrix Metalloproteinase Inhibitors/chemistry , Models, Chemical , Molecular Structure , Quantitative Structure-Activity Relationship
7.
Braz. j. microbiol ; 44(2): 629-637, 2013. ilus, tab
Article in English | LILACS | ID: lil-688594

ABSTRACT

The endophytic strain Zong1 isolated from root nodules of the legume Sophora alopecuroides was characterized by conducting physiological and biochemical tests employing gfp-marking, observing their plant growth promoting characteristics (PGPC) and detecting plant growth parameters of inoculation assays under greenhouse conditions. Results showed that strain Zong1 had an effective growth at 28 ºC after placed at 4-60 ºC for 15 min, had a wide range pH tolerance of 6.0-11.0 and salt tolerance up to 5% of NaCl. Zong1 was resistant to the following antibiotics (µg/mL): Phosphonomycin (100), Penicillin (100) and Ampicillin (100). It could grow in the medium supplemented with 1.2 mmol/L Cu, 0.1% (w/v) methylene blue and 0.1-0.2% (w/v) methyl red, respectively. Zong1 is closely related to Pseudomonas chlororaphis based on analysis the sequence of 16S rRNA gene. Its expression of the gfp gene indicated that strain Zong1 may colonize in root or root nodules and verified by microscopic observation. Furthermore, co-inoculation with Zong1 and SQ1 (Mesorhizobium sp.) showed significant effects compared to single inoculation for the following PGPC parameters: siderophore production, phosphate solubilization, organic acid production, IAA production and antifungal activity in vitro. These results suggest strains P. chlororaphi Zong1 and Mesorhizobium sp. SQ1 have better synergistic or addictive effect. It was noteworthy that each growth index of co-inoculated Zong1+SQ1 in growth assays under greenhouse conditions is higher than those of single inoculation, and showed a significant difference (p < 0.05) when compared to a negative control. Therefore, as an endophyte P. chlororaphis Zong1 may play important roles as a potential plantgrowth promoting agent.


Subject(s)
Endophytes/isolation & purification , Endophytes/metabolism , Pseudomonas/isolation & purification , Pseudomonas/metabolism , Sophora/microbiology , Antibiosis , Anti-Bacterial Agents/pharmacology , Cluster Analysis , Carboxylic Acids/metabolism , DNA, Bacterial/chemistry , DNA, Bacterial/genetics , DNA, Ribosomal/chemistry , DNA, Ribosomal/genetics , Endophytes/classification , Endophytes/genetics , Fungi/growth & development , Hydrogen-Ion Concentration , Indoleacetic Acids/metabolism , Molecular Sequence Data , Phylogeny , Plant Development , Phosphates/metabolism , Plant Roots/microbiology , Pseudomonas/classification , Pseudomonas/genetics , /genetics , Sequence Analysis, DNA , Siderophores/metabolism , Sodium Chloride/metabolism , Sophora/growth & development , Temperature
8.
Indian J Exp Biol ; 2001 May; 39(5): 493-5
Article in English | IMSEAR | ID: sea-55656

ABSTRACT

Fumonisin B1 level in culture material and in naturally contaminated corn by F. moniliforme was reduced by 30 and about 40%, respectively, by ammonia treatment. Atmospheric ammoniation of corn did not appear to be an effective method for detoxification of F. moniliforme contaminated corn.


Subject(s)
Ammonia/pharmacology , Carboxylic Acids/metabolism , Food Contamination/analysis , Fumonisins , Fusarium/drug effects , Inactivation, Metabolic , Zea mays/chemistry
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