Two Pathways for Glutamate Biosynthesis in the Syntrophic Bacterium Syntrophus aciditrophicus

Kim, Marie; Le, Huynh M.; Xie, Xiulan; Feng, Xueyang; Tang, Yinjie J.; Mouttaki, Housna; McInerney, Michael J.

doi:10.1128/aem.02323-15

Cited by 6 publications

(1 citation statement)

References 38 publications

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“…The gene was expressed in E. coli and the product was identified as a highly specific homotetrameric Re -citrate synthase, which contained one Ca 2+ per 72-kDa subunit [Kim et al, 2013]. [Kim et al, 2015]. The 13 C-labels detected in all eight amino acids identified by gas chromatographymass spectrometry were consistent with the idea that in S. aciditrophicus all biosyntheses start with acetate and CO 2 .…”

Section: Cyclohexane Carboxylate Fermentation Versus Degradationmentioning

confidence: 50%

Fermentative Cyclohexane Carboxylate Formation in Syntrophus aciditrophicus

et al. 2016

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Short-chain fatty acids such as acetic, propionic, butyric or lactic acids are typical primary fermentation products in the anaerobic feeding chain. Fifteen years ago, a novel fermentation type was discovered in the obligately anaerobic Deltaproteobacterium Syntrophus aciditrophicus. During fermentative growth with crotonate and/or benzoate, acetate is formed in the oxidative branch and cyclohexane carboxylate in the reductive branch. In both cases cyclohexa-1,5-diene-1-carboxyl-CoA (Ch1,5CoA) is a central intermediate that is either formed by a class II benzoyl-CoA reductase (fermentation of benzoate) or by reverse reactions of the benzoyl-CoA degradation pathway (fermentation of crotonate). Here, we summarize the current knowledge of the enzymology involved in fermentations yielding cyclohexane carboxylate as an excreted product. The characteristic enzymes involved are two acyl-CoA dehydrogenases specifically acting on Ch1,5CoA and cyclohex-1-ene-1-carboxyl-CoA. Both enzymes are also employed during the syntrophic growth of S. aciditrophicus with cyclohexane carboxylate as the carbon source in coculture with a methanogen. An investigation of anabolic pathways in S. aciditrophicus revealed a rather unusual pathway for glutamate synthesis involving a Re-citrate synthase. Future work has to address the unresolved question concerning which components are involved in reoxidation of the NADH formed in the oxidative branch of the unique cyclohexane carboxylate fermentation pathway in S. aciditrophicus.

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Section: Cyclohexane Carboxylate Fermentation Versus Degradationmentioning

confidence: 50%

Fermentative Cyclohexane Carboxylate Formation in Syntrophus aciditrophicus

et al. 2016

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Biosynthesis of the Amino Acids of the Glutamic Acid Family and Its Regulation

Cohen¹

2016

Microbial Biochemistry

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Rapid establishment of phenol- and quinoline-degrading consortia driven by the scoured cake layer in an anaerobic baffled ceramic membrane bioreactor

Wang

Ren

et al. 2017

Environ Sci Pollut Res

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Although toxic and refractory organics, such as phenol and quinoline, are decomposed by anaerobic bacteria, the establishment of specific degrading consortia is a relatively slow process. An anaerobic membrane bioreactor allows for complete biomass retention that can aid the establishment of phenol- and quinoline-degrading consortia. In this study, the anaerobic digestion of phenol (500 mg L) and quinoline (50 mg L) was investigated using an anaerobic baffled ceramic membrane bioreactor (ABCMBR). The results showed that, within 30 days, 99% of phenol, 98% of quinoline and 88% of chemical oxygen demand (COD) were removed. The substrate utilisation rates of the cake layer for phenol and quinoline, and specific methanogenic activity of the cake layer, were 7.58 mg phenol g mixed liquor volatile suspended solids (MLVSS) day, 8.23 mg quinoline g MLVSS day and 0.55 g COD g MLVSS day, respectively. The contribution of the cake layer to the removals of phenol and quinoline was extremely underestimated because the uncounted scoured cake layer was disregarded. Syntrophus was the key population for phenol and quinoline degradation, and it was more abundant in the cake layer than in the bulk sludge. The highly active scattered cake layer sped up the establishment of phenol- and quinoline-degrading consortia in the ABCMBR.

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Two Pathways for Glutamate Biosynthesis in the Syntrophic Bacterium Syntrophus aciditrophicus

Cited by 6 publications

References 38 publications

Fermentative Cyclohexane Carboxylate Formation in <b><i>Syntrophus aciditrophicus</i></b>

Fermentative Cyclohexane Carboxylate Formation in <b><i>Syntrophus aciditrophicus</i></b>

Biosynthesis of the Amino Acids of the Glutamic Acid Family and Its Regulation

Rapid establishment of phenol- and quinoline-degrading consortia driven by the scoured cake layer in an anaerobic baffled ceramic membrane bioreactor

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