scholarly journals Enrichment of an Endosulfan-Degrading Mixed Bacterial Culture

2000 ◽  
Vol 66 (7) ◽  
pp. 2822-2828 ◽  
Author(s):  
Tara D. Sutherland ◽  
Irene Horne ◽  
Michael J. Lacey ◽  
Rebecca L. Harcourt ◽  
Robyn J. Russell ◽  
...  
Keyword(s):  
Bacterial Culture ◽  
Parent Compound ◽  
Tween 80 ◽  
Sole Source ◽  
Gas Chromatography Mass Spectrometry ◽  
Mixed Bacterial Culture ◽  
Chemical Hydrolysis ◽  
History Of ◽  
Hydrolyzing Enzymes ◽  
Polar Product

ABSTRACT An endosulfan-degrading mixed bacterial culture was enriched from soil with a history of endosulfan exposure. Enrichment was obtained by using the insecticide as the sole source of sulfur. Chemical hydrolysis was minimized by using strongly buffered culture medium (pH 6.6), and the detergent Tween 80 was included to emulsify the insecticide, thereby increasing the amount of endosulfan in contact with the bacteria. No growth occurred in control cultures in the absence of endosulfan. Degradation of the insecticide occurred concomitant with bacterial growth. The compound was both oxidized and hydrolyzed. The oxidation reaction favored the alpha isomer and produced endosulfate, a terminal pathway product. Hydrolysis involved a novel intermediate, tentatively identified as endosulfan monoaldehyde on the basis of gas chromatography-mass spectrometry and chemical derivatization results. The accumulation and decline of metabolites suggest that the parent compound was hydrolyzed to the putative monoaldehyde, thereby releasing the sulfite moiety required for growth. The monoaldehyde was then oxidized to endosulfan hydroxyether and further metabolized to (a) polar product(s). The cytochrome P450 inhibitor, piperonyl butoxide, did not prevent endosulfan oxidation or the formation of other metabolites. These results suggest that this mixed culture is worth investigating as a source of endosulfan-hydrolyzing enzymes for use in enzymatic bioremediation of endosulfan residues.

Stimulation of β-(l → 6)-glucanase production by oxidized pustulan

1972 ◽  
Vol 18 (10) ◽  
pp. 1543-1550 ◽  
Author(s):  
Robert G. Brown
Keyword(s):  
Enzyme Activity ◽  
Isoelectric Focusing ◽  
Gel Filtration ◽  
Tween 80 ◽  
Sole Source ◽  
Cellulase Production ◽  
Low Degree ◽  
Degree Of Oxidation ◽  
High Degree ◽  
Stimulation Of

A strain of Penicillium lilacinum, isolated from soil, produced pustulanase, β-(1 → 3)-glucanase, (EC. 3.2.1.6) and cellulase (EC.3.2.1.4) when cultivated on a medium containing pustulan as the sole source of carbon. If pustulan was replaced by ketopustulan, the production of pustulanase was stimulated about 10-fold although the amount of stimulation was dependent on the degree of oxidation of pustulan. β-(1 → 3)-Glucanase production was stimulated slightly by ketopustulan; however, the degree of oxidation did not affect significantly the yield of this enzyme. Cellulase production was either unaffected by the oxidized polymer, or at higher degrees of oxidation, decreased. Tween 80 stimulated the production of the three enzymes in media containing ketopustulan with a low degree of oxidation but was inhibitory to pustulanase and cellulase production in media containing ketopustulan with a high degree of oxidation. A combination of gel filtration and isoelectric focusing revealed that each enzyme activity was attributable to at least two proteins.

scholarly journals Isolation of Mixed Bacterial Culture from Rajshahi Silk Industrial Zone and their Efficiency in Azo Dye Decolorization

2015 ◽  
Vol 8 (10) ◽  
pp. 950 ◽  
Author(s):  
Farhana Parvin ◽  
Muhammed Mizanur Rahman ◽  
Md. Mahmudul Islam ◽  
Naoshin Jahan ◽  
Md. Pallob Ebna Shaekh ◽  
...  
Keyword(s):  
Azo Dye ◽  
Bacterial Culture ◽  
Dye Decolorization ◽  
Industrial Zone ◽  
Mixed Bacterial Culture ◽  
Azo Dye Decolorization

scholarly journals Characterization of the 3-O-Methylgallate Dioxygenase Gene and Evidence of Multiple 3-O-Methylgallate Catabolic Pathways in Sphingomonas paucimobilis SYK-6

2004 ◽  
Vol 186 (15) ◽  
pp. 4951-4959 ◽  
Author(s):  
Daisuke Kasai ◽  
Eiji Masai ◽  
Keisuke Miyauchi ◽  
Yoshihiro Katayama ◽  
Masao Fukuda
Keyword(s):  
Sole Source ◽  
Cell Extract ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Insertion Mutant ◽  
Sphingomonas Paucimobilis ◽  
Spectrometry Analysis ◽  
Dioxygenase Gene ◽  
Transformation Activity ◽  
Extradiol Dioxygenases

ABSTRACT Sphingomonas paucimobilis SYK-6 is able to grow on various lignin-derived biaryls as the sole source of carbon and energy. These compounds are degraded to vanillate and syringate by the unique and specific enzymes in this strain. Vanillate and syringate are converted to protocatechuate (PCA) and 3-O-methylgallate (3MGA), respectively, by the tetrahydrofolate-dependent O-demethylases. Previous studies have suggested that these compounds are further degraded via the PCA 4,5-cleavage pathway. However, our subsequent analysis of the ligB insertion mutant, which encodes the β subunit of PCA 4,5-dioxygenase, suggested that at least one alternative route is involved in 3MGA degradation. In the present study, we isolated the desZ gene, which confers 3MGA degradation activity on Escherichia coli. The deduced amino acid sequence of desZ showed ca. 20 to 43% identity with the type II extradiol dioxygenases. Gas chromatography-mass spectrometry analysis suggested that DesZ catalyzes the 3,4-cleavage of 3MGA. Disruption of both desZ and ligB in SYK-6 resulted in loss of the dioxygen-dependent 3MGA transformation activity, but the resulting mutant retained the ability to grow on syringate. We found that the cell extract of the desZ ligB double mutant was able to convert 3MGA to gallate when tetrahydrofolate was added to the reaction mixture, and the cell extract of this mutant degraded gallate to the same degree as the wild type did. All these results suggest that syringate is degraded through multiple 3MGA degradation pathways in which ligAB, desZ, 3MGA O-demethylase, and gallate dioxygenase are participants.

scholarly journals Biodesulfurization of Naphthothiophene and Benzothiophene through Selective Cleavage of Carbon-Sulfur Bonds by Rhodococcus sp. Strain WU-K2R

2002 ◽  
Vol 68 (8) ◽  
pp. 3867-3872 ◽  
Author(s):  
Kohtaro Kirimura ◽  
Toshiki Furuya ◽  
Rika Sato ◽  
Yoshitaka Ishii ◽  
Kuniki Kino ◽  
...  
Keyword(s):  
Sole Source ◽  
Diesel Oil ◽  
The Other ◽  
Mass Spectrometry Analysis ◽  
Gas Chromatography Mass Spectrometry ◽  
Structural Isomer ◽  
Degradation Pathways ◽  
Spectrometry Analysis ◽  
Specific Degradation ◽  
Rhodococcus Sp

ABSTRACT Naphtho[2,1-b]thiophene (NTH) is an asymmetric structural isomer of dibenzothiophene (DBT), and in addition to DBT derivatives, NTH derivatives can also be detected in diesel oil following hydrodesulfurization treatment. Rhodococcus sp. strain WU-K2R was newly isolated from soil for its ability to grow in a medium with NTH as the sole source of sulfur, and growing cells of WU-K2R degraded 0.27 mM NTH within 7 days. WU-K2R could also grow in the medium with NTH sulfone, benzothiophene (BTH), 3-methyl-BTH, or 5-methyl-BTH as the sole source of sulfur but could not utilize DBT, DBT sulfone, or 4,6-dimethyl-DBT. On the other hand, WU-K2R did not utilize NTH or BTH as the sole source of carbon. By gas chromatography-mass spectrometry analysis, desulfurized NTH metabolites were identified as NTH sulfone, 2′-hydroxynaphthylethene, and naphtho[2,1-b]furan. Moreover, since desulfurized BTH metabolites were identified as BTH sulfone, benzo[c][1,2]oxathiin S-oxide, benzo[c][1,2]oxathiin S,S-dioxide, o-hydroxystyrene, 2-(2′-hydroxyphenyl)ethan-1-al, and benzofuran, it was concluded that WU-K2R desulfurized NTH and BTH through the sulfur-specific degradation pathways with the selective cleavage of carbon-sulfur bonds. Therefore, Rhodococcus sp. strain WU-K2R, which could preferentially desulfurize asymmetric heterocyclic sulfur compounds such as NTH and BTH through the sulfur-specific degradation pathways, is a unique desulfurizing biocatalyst showing properties different from those of DBT-desulfurizing bacteria.

Memory as Malady and Therapy in Freud and Hegel

1981 ◽  
Vol 12 (2) ◽  
pp. 33-50
Author(s):  
David Farrell Krell
Keyword(s):  
Good Deal ◽  
Sole Source ◽  
History Of Philosophy ◽  
Freudian Psychoanalysis ◽  
American Universities ◽  
Philosophical Thought ◽  
Psychological Phenomena ◽  
History Of

AbstractThe following paper, delivered as a lecture to the philosophy departments of a number of American universities in 1979, traces a parallel between Hegelian phenomenology and Freudian psychoanalysis. It stems from a project I have been working on for several years now entitled Erinnerungsversuch or "Essay in Remembrance. " In my studies of Freud and Hegel for that project I was struck by the importance of memory for their work, not only as a field of investigation but also as a method of the investigation itself. Remembering and forgetting are the crucial events for both psychoanalysis and phenomenology, crucial yet maddeningly intertwined, so that while memory seems eminently subject to malfunction and even illness it remains the sole source of insight and cure. I therefore determined to extend the parallel as far as it would go-perhaps even farther-and the present paper is the result. I am of course aware that Hegel was not a psychotherapist, Freud not a systematic philosopher, and realize that if essays like this one may be excused at all it is only because they eventually grow silent and allow irreconcilable differences to reassert themselves. Yet there is a sense in which Hegel's creative recapitulation of the history of philosophy, seeking as it does to liberate philosophical thought from a crippling self-ignorance, amounts to therapy of spirit; and there is a sense in which Freudian therapy must shatter traditional prejudices in our thoughts about what the psyche or spirit is, by letting psychological phenomena show themselves as they are. I have tried to make the parallel as concrete as possible, shunning Freud's metapsychology and turning instead to one of his earliest accounts of psychoanalytic praxis, eschewing sweeping remarks about Hegel's "system" and concentrating on just a few pages from the Phenomenology. Readers trained in philosophy will know that a few pages of Hegel are bound to contain labyrinths. I hope that my psychologist-readers will overlook the oversimplified presentation of Freud-which results partly from the lecture form-and will forgive my unwillingness to make Hegel's thought seem less demanding than it is. Finally, if I am right, the Freud-Hegel parallel with respect to memory tells us a good deal not only about this fascinating faculty but also about that singular creature who is so ardent to remember and so prone to forget.

Mineralisation of 1,2-dibromoethane and other brominated aliphatics under aerobic conditions

1997 ◽  
Vol 36 (10) ◽  
pp. 17-25
Author(s):  
Luisa M. Freitas dos Santos ◽  
Andrew G. Livingston
Keyword(s):  
Mixed Culture ◽  
Soil Remediation ◽  
Bacterial Culture ◽  
Sole Source ◽  
Pollutant Concentration ◽  
Environmental Contaminant ◽  
Anaerobic Conditions ◽  
Aerobic Conditions ◽  
Laboratory Conditions ◽  
Brominated Compounds

1,2-dibromoethane (DBE) is a common environmental contaminant; it is potentially carcinogenic and has been detected in soil and groundwater supplies. Most of the biodegradation studies to date have been performed under anaerobic conditions or in the context of soil remediation, where the pollutant concentration was in the ppb range. The aim of this work was to find a bacterial culture (axenic or mixed) capable of complete aerobic mineralisation of concentrations of DBE up to 1 g L−1 under well controlled laboratory conditions. A mixed culture capable of degrading DBE as a sole source of carbon has been enriched. In order to verify biodegradation, formation of biodegradation products as well as the disappearance of DBE were measured. The ability of this culture to degrade other chlorinated and brominated compounds has also been tested. Successful degradation of bromoethane, bromoethanol and bromochloroethane was achieved.

Enrichment of a Mixed Bacterial Culture with a High Polyhydroxyalkanoate Storage Capacity

2009 ◽  
Vol 10 (4) ◽  
pp. 670-676 ◽  
Author(s):  
Katja Johnson ◽  
Yang Jiang ◽  
Robbert Kleerebezem ◽  
Gerard Muyzer ◽  
Mark C. M. van Loosdrecht
Keyword(s):  
Storage Capacity ◽  
Bacterial Culture ◽  
Mixed Bacterial Culture
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