scholarly journals Metabolism of dibenzo[1,4]dioxan by a Pseudomonas species

1979 ◽  
Vol 180 (3) ◽  
pp. 639-645 ◽  
Author(s):  
G M Klečka ◽  
D T Gibson
Keyword(s):  
Parental Strain ◽  
Culture Medium ◽  
Crystalline Form ◽  
Pseudomonas Sp ◽  
Anaerobic Conditions ◽  
Cell Extracts ◽  
Pseudomonas Species ◽  
Chemical Techniques ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

Pseudomonas sp. N.C.I.B. 9816 strain 11, when grown on salicylate in the presence of dibenzo[1,4]dioxan, accumulated cis-1,2-dihydroxy-1,2-dihydrodibenzo[1,4]dioxan and 2-hydroxydibenzo[1,4]dioxan in the culture medium. Each metabolite was isolated in crystalline form and identified by a variety of conventional chemical techniques. Crude cell extracts prepared from the parental strain grown with naphthalene oxidized cis-1,2-dihydroxy-1,2-dihydrodibenzo[1,4]dioxan under both aerobic and anaerobic conditions to 1,2-dihydroxydibenzo[1,4]dioxan. Further degradation of this metabolite was not detected.

Aerobic purification of N5,N10-methylenetetrahydromethanopterin dehydrogenase, separated from N5,N10-methenyltetrahydromethanopterin cyclohydrolase, from Methanobacterium thermoautotrophicum strain Marburg

1989 ◽  
Vol 35 (4) ◽  
pp. 499-507 ◽  
Author(s):  
Biswarup Mukhopadhyay ◽  
Lacy Daniels
Keyword(s):  
Enzyme Activity ◽  
Ammonium Sulfate ◽  
Dehydrogenase Activity ◽  
Specific Activity ◽  
Methanobacterium Thermoautotrophicum ◽  
Anaerobic Conditions ◽  
Cell Extracts ◽  
First Time ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

The N5,N10-methylenetetrahydromethanopterin dehydrogenase from Methanobacterium thermoautotrophicum strain Marburg has been purified with reasonable yield and much higher specific activity than previously reported. For the first time it has been shown that both N5,N10-methylenetetrahydromethanopterin dehydrogenase and N5,N10-methenyltetrahydromethanopterin cyclohydrolase activities were stable under air and could be purified using aerobic operations. The dehydrogenase activity from Methanobacterium thermoautotrophicum Marburg was stable in phosphate buffer with or without glycerol or ammonium sulfate under both aerobic and anaerobic conditions. However, the presence of either 2-mercaptoethanol or dithiothreitol in the enzyme solution destroyed the enzyme activity during both aerobic and anaerobic incubations. Dehydrogenase was purified 62-fold using Phenyl-Sepharose and DEAE-Sephadex chromatography in succession under air. Both of these chromatographic methods separated dehydrogenase activity from N5,N10-methenyltetrahydromethanopterin cyclohydrolase; DEAE-Sephadex provided the best separation. Phenyl-Sepharose chromatography of the supernatant of cell extracts containing ammonium sulfate at 60% of saturation provided a 4.7-fold purification and 98% recovery of cyclohydrolase; this result established the air stability of N5,N10-methenyltetrahydromethanopterin cyclohydrolase from Methanobacterium thermoautotrophicum Marburg.Key words: methylenetetrahydromethanopterin dehydrogenase, methenyltetrahydromethanopterin cyclohydrolase, Methanobacterium, aerobic purification, oxygen stability.

Oxygen concentration affects frequency and range of transconjugants for the incompatibility (Inc) P-1 and P-7 plasmids pBP136 and pCAR1

2020 ◽  
Vol 85 (4) ◽  
pp. 1005-1015
Author(s):  
Kentaro Ochi ◽  
Maho Tokuda ◽  
Kosuke Yanagiya ◽  
Chiho Suzuki-Minakuchi ◽  
Hideaki Nojiri ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Anaerobic Condition ◽  
Environmental Samples ◽  
Aerobic Condition ◽  
Recipient Strain ◽  
Donor Strain ◽  
Anaerobic Conditions ◽  
Filter Mating ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

ABSTRACT The frequency of transconjugants were compared for the incompatibility (Inc) P-1 and P-7 plasmids pBP136 and pCAR1 under aerobic and anaerobic conditions. Filter mating assays were performed with one donor strain and one recipient strain using different donors of Pseudomonas and recipient strains, including Pseudomonas, Pantoea, and Buttiauxella. Under anaerobic condition, frequencies of transconjugants for both plasmids were 101-103-fold lower than those under aerobic condition regardless of whether aerobically or anaerobically grown donors and recipients were used. To compare the transconjugant ranges under aerobic and anaerobic conditions, conjugation was performed between the donor of pBP136 and recipient bacteria extracted from environmental samples. Several transconjugants were uniquely obtained from each aerobic or anaerobic condition. Our findings indicate that a plasmid can differently spread among bacteria depending on the oxygen concentrations of the environment.

PRODUCTION AND PROPERTIES OF 2,3-BUTANEDIOL: VII. FERMENTATION OF WHEAT BY AEROBACILLUS POLYMYXA UNDER AEROBIC AND ANAEROBIC CONDITIONS

1946 ◽  
Vol 24f (1) ◽  
pp. 1-11 ◽  
Author(s):  
G. A. Adams
Keyword(s):  
Carbon Dioxide ◽  
Anaerobic Fermentation ◽  
Anaerobic Conditions ◽  
Mechanical Agitation ◽  
Fermentation Time ◽  
Aerobic Conditions ◽  
Ethanol Formation ◽  
Time Required ◽  
Aerobic And Anaerobic ◽  
Aerobic And Anaerobic Conditions

Aeration by mechanical agitation of 15% wheat mash fermented by Aerobacillus polymyxa inhibited the formation of 2,3-butanediol and particularly of ethanol. Aeration of similar mashes by passage of finely dispersed air or oxygen at the rate of 333 ml. per minute per litre of mash increased the rate of formation and yield of 2,3-butanediol but inhibited ethanol formation. However, the over-all time required for the completion of fermentation was not shortened from the usual 72 to 96 hr. required for unaerated mashes. There was no evidence of a shift from fermentative to oxidative dissimilation. Under aerobic conditions, the final butanediol–ethanol ratio was approximately 3:1. Anaerobic conditions, as produced by the passage of nitrogen or hydrogen through the mash, increased the rate of formation of both butanediol and ethanol and shortened the fermentation time to about 48 hr. Under these conditions, the butanediol–ethanol ratio was reduced to about 1.3:1.0. Carbon dioxide gave a butanediol–ethanol ratio resembling that of anaerobic fermentation but did not reduce fermentation time.

scholarly journals Optimizing characteristics in mineral insulating oil used in high power transformers

2019 ◽  
pp. 222-228
Author(s):  
Irina Alina Chera Anghel ◽  
Loredana Popescu
Keyword(s):  
Mineral Oil ◽  
The Other ◽  
Power Transformers ◽  
Anaerobic Conditions ◽  
Mineral Oils ◽  
Insulating Liquid ◽  
Different Characteristics ◽  
Aerobic And Anaerobic ◽  
Good Heat ◽  
Aerobic And Anaerobic Conditions

The most commonly used insulating liquid in transformers is mineral oil. Special synthetic applications such as silicone, ester, perchloroethene, etc. are used today in special applications, with different characteristics, very low or nonexistent toxicity to mineral oils used in transformers. On the other hand, they have a much better biodegradability than mineral oils in both aerobic and anaerobic conditions. But they cannot directly replace the mineral oil in operation or in repaired units. They have dielectric properties and good heat transfer but have limited their use to special transformers due to the relatively high cost and availability.

Sign in / Sign up

Export Citation Format

Share Document