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Methanosarcina barkeri

About: Methanosarcina barkeri is a research topic. Over the lifetime, 703 publications have been published within this topic receiving 32151 citations.


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Journal ArticleDOI
TL;DR: Polar ether lipids extracted from 15 methanogenic bacteria, representative of seven genera, were screened by nuclear magnetic resonance and thin layer chromatography for the presence of hydroxyl groups on the C20-phytanyl moieties and confirmed for Methanosaeta concilii.

85 citations

Journal ArticleDOI
TL;DR: The results suggested an active site geometry in which coenzyme M is bound both by S-coordination to zinc, and electrostatic interaction of the sulfonate with a cationic group on the enzyme.

85 citations

Journal ArticleDOI
TL;DR: In this paper, the effect of pH, bicarbonate alkalinity and trace elements on the methane fermentation of pure aqueous solutions of methanol has been investigated.

84 citations

Journal ArticleDOI
TL;DR: The numbers of pectinolytic anaerobes varied seasonally in both sediments, and were highest during the fall after sedimentation of algal blooms and/or leaf detritus, and the pH remaining neutral.
Abstract: SUMMARY: Anaerobic digestion of pectin by bacteria was examined in two freshwater lakes in Wisconsin and in defined laboratory cultures of species prevalent in the lake sediment. The turnover times for pectin biodegradation to methane in sediments incubated at in situ temperature were much longer (100 h in Lake Mendota and 185 h in Knaack Lake) than either that observed for glucose (12 h in Lake Mendota) or previously reported for acetate (0·22 h in Lake Mendota). The numbers of pectinolytic anaerobes varied seasonally in both sediments (102--105 and 103--105 ml-1 in Knaack Lake and Lake Mendota, respectively), and were highest during the fall after sedimentation of algal blooms and/or leaf detritus. Clostridium butyricum was identified as a prevalent pectinolytic anaerobe in both lakes. In mono-culture pectin fermentations, C. butyricum produced methanol, H2/CO2, acetate, ethanol and butyrate; growth stopped in the presence of excess energy source when the pH fell to 4·3. In co-culture pectin fermentations of C. butyricum/Methanosarcina barkeri, H2/CO2, methanol and acetate were detected as intermediary metabolites, and pectin was completely degraded to CH4 and CO2, the pH remaining neutral. 14C-radiotracer analysis substantiated the simultaneous conversion of H2/CO2, methanol and acetate to CH4 by M. barkeri as these metabolites were generated from pectin hydrolysis by C. butyricum.

83 citations

Journal ArticleDOI
TL;DR: Thermostability as well as activity of formyltransferase was dramatically increased in the presence of salts, 1.5 M being required for optimal stabilization and 1.2 M for half-maximal activity.
Abstract: N-Formylmethanofuran(CHO-MFR): tetrahydromethanopterin(H4MPT) formyltransferase (for-myltransferase) from the extremely thermophilic Methanopyrus kandleri was purified over 100-fold to apparent homogeneity with a 54% yield. The monomeric enzyme had an apparent molecular mass of 35 kDa. The N-terminal amino acid sequence of the polypeptide was determined. The formyltransferase was found to be absolutely dependent on the presence of phosphate or sulfate salts for activity. The ability of salts to activate the enzyme decreased in the order K2HPO4 > (NH4)2SO4 > K2SO4 > Na2SO4 > Na2HPO4. The salts KCl, NaCl and NH4Cl did not activate the enzyme. The dependence of activity on salt concentration showed a sigmoidal curve. For half-maximal activity, 1 M K2HPO4 and 1.2 M (NH4)2SO4 were required. A detailed kinetic analysis revcaled that phosphates and sulfates both affected the Vmax rather than the Km for CHO-MFR and H4MPT. At the optimal salt concentration and at 65°C, the Vmax was 2700 U/mg (1 U = 1 μmol/min), the Km for CHO-MFR was 50 μM and the Km for H4MPT was 100 μM. At 90°C, the temperature optimum of the enzyme, the Vmax was about 2.5-fold higher than at 65°C. Thermostability as well as activity of formyltransferase was dramatically increased in the presence of salts, 1.5 M being required for optimal stabilization. The efficiency of salts in protecting formyltransferase from heat inactivation at 90°C decreased in the order K2HPO4= (NH4)2SO4≫ KCI = NH4Cl = NaCl ≫ Na2SO4 > Na2HPO4. The catalytic mechanism of formyltransferase was determined to be of the ternary-complex type. The properties of the enzyme from M. kandleri are compared with those of formyltransferase from Methanobacterium thermoautotrophicum, Methanosarcina barkeri and Archaeoglobus fulgidus.

82 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20237
202212
202112
202012
20197
201818