scholarly journals Unusual Starch Degradation Pathway via Cyclodextrins in the Hyperthermophilic Sulfate-Reducing Archaeon Archaeoglobus fulgidus Strain 7324

2007 ◽  
Vol 189 (24) ◽  
pp. 8901-8913 ◽  
Author(s):  
Antje Labes ◽  
Peter Schönheit
Keyword(s):  
Degradation Pathway ◽  
Archaeoglobus Fulgidus ◽  
Starch Degradation ◽  
Cyclodextrin Glucanotransferase ◽  
Gene Encoding ◽  
Thermococcus Litoralis ◽  
Sulfate Reducing ◽  
Combined Action ◽  
Archaeoglobus Fulgidus Strain 7324 ◽  
Modified Embden Meyerhof Pathway

ABSTRACT The hyperthermophilic archaeon Archaeoglobus fulgidus strain 7324 has been shown to grow on starch and sulfate and thus represents the first sulfate reducer able to degrade polymeric sugars. The enzymes involved in starch degradation to glucose 6-phosphate were studied. In extracts of starch-grown cells the activities of the classical starch degradation enzymes, α-amylase and amylopullulanase, could not be detected. Instead, evidence is presented here that A. fulgidus utilizes an unusual pathway of starch degradation involving cyclodextrins as intermediates. The pathway comprises the combined action of an extracellular cyclodextrin glucanotransferase (CGTase) converting starch to cyclodextrins and the intracellular conversion of cyclodextrins to glucose 6-phosphate via cyclodextrinase (CDase), maltodextrin phosphorylase (Mal-P), and phosphoglucomutase (PGM). These enzymes, which are all induced after growth on starch, were characterized. CGTase catalyzed the conversion of starch to mainly β-cyclodextrin. The gene encoding CGTase was cloned and sequenced and showed highest similarity to a glucanotransferase from Thermococcus litoralis. After transport of the cyclodextrins into the cell by a transport system to be defined, these molecules are linearized via a CDase, catalyzing exclusively the ring opening of the cyclodextrins to the respective maltooligodextrins. These are degraded by a Mal-P to glucose 1-phosphate. Finally, PGM catalyzes the conversion of glucose 1-phosphate to glucose 6-phosphate, which is further degraded to pyruvate via the modified Embden-Meyerhof pathway.

scholarly journals Thermococcus bergensis sp. nov., a Novel Hyperthermophilic Starch-Degrading Archaeon

Biology ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 387
Author(s):  
Nils-Kåre Birkeland ◽  
Boyke Bunk ◽  
Cathrin Spröer ◽  
Hans-Peter Klenk ◽  
Peter Schönheit
Keyword(s):  
Novel Species ◽  
Hot Water ◽  
Archaeoglobus Fulgidus ◽  
Rrna Gene ◽  
Oil Reservoir ◽  
Sulfate Reducing ◽  
Sugar Degradation ◽  
Distinct Lineage ◽  
Archaeoglobus Fulgidus Strain 7324 ◽  
The 16S Rrna Gene

A novel hyperthermophilic archaeon, termed strain T7324T, was isolated from a mixed sulfate-reducing consortium recovered from hot water produced from a deep North Sea oil reservoir. The isolate is a strict anaerobic chemo-organotroph able to utilize yeast extract or starch as a carbon source. The genes for a number of sugar degradation enzymes and glutamate dehydrogenase previously attributed to the sulfate reducing strain of the consortium (Archaeoglobus fulgidus strain 7324) were identified in the nearly completed genome sequence. Sequence analysis of the 16S rRNA gene placed the strain in the Thermococcus genus, but with an average nucleotide identity that is less than 90% to its closest relatives. Phylogenomic treeing reconstructions placed the strain on a distinct lineage clearly separated from other Thermococcus spp. The results indicate that the strain T7324T represents a novel species, for which the name Thermococcus bergensis sp. nov. is proposed. The type strain is T7324T (=DSM 27149T = KCTC 15808T).

Anaerobic Degradation Pathway of Linear Alkylbenzene Sulfonates (LAS) in Sulfate-Reducing Marine Sediments

2010 ◽  
Vol 44 (5) ◽  
pp. 1670-1676 ◽  
Author(s):  
Pablo A. Lara-Martín ◽  
Abelardo Gómez-Parra ◽  
José Luis Sanz ◽  
Eduardo González-Mazo
Keyword(s):  
Marine Sediments ◽  
Anaerobic Degradation ◽  
Degradation Pathway ◽  
Linear Alkylbenzene ◽  
Sulfate Reducing ◽  
Linear Alkylbenzene Sulfonates

Corrosion Behaviors of 0Cr18Ni9 Stainless Steel under the Combination Action of Sulfate-Reducing Bacteria and V.natriegens

2011 ◽  
Vol 356-360 ◽  
pp. 161-164
Author(s):  
Cai Xiang Gu ◽  
Xiao Ming Zhao ◽  
Yan Sheng Yin ◽  
Gui Jun Ji
Keyword(s):  
Stainless Steel ◽  
Corrosion Potential ◽  
Sea Water ◽  
Microbial Corrosion ◽  
Sulfate Reducing ◽  
Facultative Anaerobic ◽  
Corrosion Behaviors ◽  
Microbial Film ◽  
Combined Action ◽  
Reducing Bacteria

Advantage strains SRB and V.natriegens were obtained from the China East Sea for this study. Polarization curves, corrosion potential, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses were adopted in order to investigate the corrosion behaviors of 0Cr18Ni9 stainless steel under the combination action of anaerobic SRB and facultative anaerobic V.natriegens, The characteristics and mechanisms of microbial corrosion action in sea water were analyzed in this paper. The results show that SRB and V.natriegens promote each other’s growth when cultivated in the mixed microbe medium, in which the rate of corrosion is higher than that in the single microbe; Under the combined action of the mixed microbe, the microbial film gets wider and thicker, and corrosion products and metabolite are produced, which furthermore accelerates the passivation and pit corrosion to the 0Cr18Ni9 stainless steel.

scholarly journals Cyclohexa-1,5-Diene-1-Carbonyl-Coenzyme A (CoA) Hydratases of Geobacter metallireducens and Syntrophus aciditrophicus: Evidence for a Common Benzoyl-CoA Degradation Pathway in Facultative and Strict Anaerobes

2006 ◽  
Vol 189 (3) ◽  
pp. 1055-1060 ◽  
Author(s):  
Franziska Peters ◽  
Yoshifumi Shinoda ◽  
Michael J. McInerney ◽  
Matthias Boll
Keyword(s):  
Coenzyme A ◽  
Anaerobic Bacteria ◽  
Degradation Pathway ◽  
Ring Cleavage ◽  
Strictly Anaerobic ◽  
Significant Activity ◽  
Geobacter Metallireducens ◽  
Sulfate Reducing ◽  
Coa Reductase ◽  
Syntrophus Aciditrophicus

ABSTRACT In the denitrifying bacterium Thauera aromatica, the central intermediate of anaerobic aromatic metabolism, benzoyl-coenzyme A (CoA), is dearomatized by the ATP-dependent benzoyl-CoA reductase to cyclohexa-1,5-diene-1-carbonyl-CoA (dienoyl-CoA). The dienoyl-CoA is further metabolized by a series of β-oxidation-like reactions of the so-called benzoyl-CoA degradation pathway resulting in ring cleavage. Recently, evidence was obtained that obligately anaerobic bacteria that use aromatic growth substrates do not contain an ATP-dependent benzoyl-CoA reductase. In these bacteria, the reactions involved in dearomatization and cleavage of the aromatic ring have not been shown, so far. In this work, a characteristic enzymatic step of the benzoyl-CoA pathway in obligate anaerobes was demonstrated and characterized. Dienoyl-CoA hydratase activities were determined in extracts of Geobacter metallireducens (iron reducing), Syntrophus aciditrophicus (fermenting), and Desulfococcus multivorans (sulfate reducing) cells grown with benzoate. The benzoate-induced genes putatively coding for the dienoyl-CoA hydratases in the benzoate degraders G. metallireducens and S. aciditrophicus were heterologously expressed and characterized. Both gene products specifically catalyzed the reversible hydration of dienoyl-CoA to 6-hydroxycyclohexenoyl-CoA (Km , 80 and 35 μM; V max, 350 and 550 μmol min−1 mg−1, respectively). Neither enzyme had significant activity with cyclohex-1-ene-1-carbonyl-CoA or crotonyl-CoA. The results suggest that benzoyl-CoA degradation proceeds via dienoyl-CoA and 6-hydroxycyclohexanoyl-CoA in strictly anaerobic bacteria. The steps involved in dienoyl-CoA metabolism appear identical in all nonphotosynthetic anaerobic bacteria, although totally different benzene ring-dearomatizing enzymes are present in facultative and obligate anaerobes.

scholarly journals Identification of an Acetoacetyl Coenzyme A Synthetase-Dependent Pathway for Utilization of l-(+)-3-Hydroxybutyrate in Sinorhizobium meliloti

2002 ◽  
Vol 184 (6) ◽  
pp. 1571-1577 ◽  
Author(s):  
Punita Aneja ◽  
Renata Dziak ◽  
Guo-Qin Cai ◽  
Trevor C. Charles
Keyword(s):  
Sinorhizobium Meliloti ◽  
Direct Evidence ◽  
Coenzyme A ◽  
Sole Source ◽  
Degradation Pathway ◽  
Synthetase Activity ◽  
Gene Encoding ◽  
Carbon Store ◽  
Utilization Pathway ◽  
Dependent Pathway

ABSTRACT d-(−)-3-Hydroxybutyrate (DHB), the immediate depolymerization product of the intracellular carbon store poly-3-hydroxybutyrate (PHB), is oxidized by the enzyme 3-hydroxybutyrate dehydrogenase to acetoacetate (AA) in the PHB degradation pathway. Externally supplied DHB can serve as a sole source of carbon and energy to support the growth of Sinorhizobium meliloti. In contrast, wild-type S. meliloti is not able to utilize the l-(+) isomer of 3-hydroxybutyrate (LHB) as a sole source of carbon and energy. In this study, we show that overexpression of the S. meliloti acsA2 gene, encoding acetoacetyl coenzyme A (acetoacetyl-CoA) synthetase, confers LHB utilization ability, and this is accompanied by novel LHB-CoA synthetase activity. Kinetics studies with the purified AcsA2 protein confirmed its ability to utilize both AA and LHB as substrates and showed that the affinity of the enzyme for LHB was clearly lower than that for AA. These results thus provide direct evidence for the LHB-CoA synthetase activity of the AcsA2 protein and demonstrate that the LHB utilization pathway in S. meliloti is AcsA2 dependent.

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