Anaerobic degradation of 2-methylbenzoic acid by a methanogenic consortium

1993 ◽  
Vol 39 (8) ◽  
pp. 812-816 ◽  
Author(s):  
Kathleen L. Londry ◽  
Phillip M. Fedorak
Keyword(s):  
Molecular Weight ◽  
Sewage Sludge ◽  
Anaerobic Degradation ◽  
Trimethylsilyl Derivative ◽  
Acid Degradation ◽  
Enrichment Cultures ◽  
Acid Hydroxylation ◽  
Lag Times ◽  
Methanogenic Consortium

2-Methylbenzoic has been detected as a metabolite in anaerobic consortia that degrade m-cresol and it was found to accumulate in cultures incubated under methanogenic conditions. This study was initiated to determine whether 2-methylbenzoic acid could be degraded under methanogenic conditions. Near stoichiometric amounts of methane were obtained from 2-methylbenzoic acid in enrichment cultures inoculated with 25% (v/v) domestic anaerobic sewage sludge. However, lag times of 12–36 weeks typically were required before 2-methylbenzoic acid degradation began, and it was difficult to maintain the activity of the cultures. A transient metabolite was detected but not identified. It appeared to be the product of 2-methylbenzoic acid hydroxylation because its trimethylsilyl derivative had a molecular weight of 296, but it was not 4-hydroxy-2-methylbenzoic acid, the intermediate of m-cresol metabolism from which 2-methylbenzoic acid likely originates.Key words: anaerobic, methane, 2-methylbenzoic acid.

scholarly journals Anticoagulant Properties of a Green Algal Rhamnan-type Sulfated Polysaccharide and Its Low-molecular-weight Fragments Prepared by Mild Acid Degradation

Marine Drugs ◽  
2018 ◽  
Vol 16 (11) ◽  
pp. 445 ◽  
Author(s):  
Xue Liu ◽  
Peng Du ◽  
Xiao Liu ◽  
Sujian Cao ◽  
Ling Qin ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Anticoagulant Activity ◽  
Sulfated Polysaccharide ◽  
Low Molecular Weight ◽  
Thrombin Time ◽  
Acid Degradation ◽  
Molecular Weights ◽  
Green Algal

The active sulfated polysaccharide from seaweed possesses important pharmaceutical and biomedical potential. In the study, Monostroma sulfated polysaccharide (MSP) was obtained from Monostroma angicava, and the low-molecular-weight fragments of MSP (MSP-Fs: MSP-F1–MSP-F6) were prepared by controlled acid degradation. The molecular weights of MSP and MSP-F1–MSP-F6 were 335 kDa, 240 kDa, 90 kDa, 40 kDa, 24 kDa, 12 kDa, and 6.8 kDa, respectively. The polysaccharides were sulfated rhamnans that consisted of →3)-α-l-Rhap-(1→ and →2)-α-l-Rhap-(1→ units with partial sulfation at C-2 of →3)-α-l-Rhap-(1→ and C-3 of →2)-α-l-Rhap-(1→. Anticoagulant properties in vitro of MSP and MSP-F1–MSP-F6 were evaluated by studying the activated partial thromboplastin time, thrombin time, and prothrombin time. Anticoagulant activities in vivo of MSP and MSP-F4 were further evaluated; their fibrin(ogen)olytic activities in vivo and thrombolytic properties in vitro were also assessed by D-dimer, fibrin degradation products, plasminogen activator inhibitior-1, and clot lytic rate assays. The results showed that MSP and MSP-F1–MSP-F4 with molecular weights of 24–240 kDa had strong anticoagulant activities. A decrease in the molecular weight of MSP-Fs was accompanied by a decrease in the anticoagulant activity, and higher anticoagulant activity requires a molecular weight of over 12 kDa. MSP and MSP-F4 possessed strong anticoagulant activities in vivo, as well as high fibrin(ogen)olytic and thrombolytic activities. MSP and MSP-F4 have potential as drug or helpful food supplements for human health.

Effect of the sequence ultrasonic operation on anaerobic degradation of sewage sludge

2016 ◽  
Vol 112 ◽  
pp. 66-71 ◽  
Author(s):  
Xianjin Li ◽  
Tong Zhu ◽  
Kuo Zhang ◽  
Liting Lv ◽  
Tianyu Chai ◽  
...  
Keyword(s):  
Sewage Sludge ◽  
Anaerobic Degradation

Anaerobic Degradation of PCP and Phenol in Fixed-Film Reactors: The Influence of an Additional Substrate

1991 ◽  
Vol 24 (3-4) ◽  
pp. 431-436 ◽  
Author(s):  
H. V. Hendriksen ◽  
S. Larsen ◽  
B. K. Ahring
Keyword(s):  
Sewage Sludge ◽  
Carbon Source ◽  
Anaerobic Degradation ◽  
Degradation Products ◽  
Phenol Degradation ◽  
Treatment Plant ◽  
Continuous Operation ◽  
Mineral Medium ◽  
Fixed Film ◽  
Digested Sewage Sludge

The anaerobic degradation of pentachlorophenol (PCP) and phenol was examined in two lab-scale fixed-film reactors. Anaerobic digested sewage sludge from a municipal treatment plant was used as inoculum. The reactors were fed a mineral medium containing PCP (1-2 mg/l) and phenol (4-6 mg/l). In addition one of the reactors received 1 g/l glucose as an easily degradable carbon source. After 6 months of continuous operation, the removal of PCP in the reactor with no glucose added was approximately 60%, whereas the removal in the reactor with glucose reached 98%. Tetrachlorophenol (TeCP) and trichloro-phenol (TCP) were found as degradation products and the removal of these compounds was also significantly enhanced by the presence of glucose. Phenol degradation was approximately 70% with glucose added and 95% without glucose.

Rapid anaerobic degradation of toxaphene in sewage sludge

Chemosphere ◽  
2000 ◽  
Vol 40 (9-11) ◽  
pp. 1213-1220 ◽  
Author(s):  
Hans-Rudolf Buser ◽  
Peter Haglund ◽  
Markus D. Müller ◽  
Thomas Poiger ◽  
Christoffer Rappe
Keyword(s):  
Sewage Sludge ◽  
Anaerobic Degradation

Anaerobic Degradation of Acifluorfen by Different Enrichment Cultures

1994 ◽  
Vol 42 (5) ◽  
pp. 1232-1236 ◽  
Author(s):  
Mara Gennari ◽  
Michele Negre ◽  
Roberto Ambrosoli ◽  
Vincenza Andreoni ◽  
Macro Vincenti ◽  
...  
Keyword(s):  
Anaerobic Degradation ◽  
Enrichment Cultures

Simplified mechanistic model for the two-stage anaerobic degradation of sewage sludge

2014 ◽  
Vol 36 (10) ◽  
pp. 1334-1346 ◽  
Author(s):  
Andrés Donoso-Bravo ◽  
Sara Pérez-Elvira ◽  
Fernando Fdz-Polanco
Keyword(s):  
Sewage Sludge ◽  
Anaerobic Degradation ◽  
Mechanistic Model ◽  
Two Stage

scholarly journals Microbial Degradation of Octamethylcyclotetrasiloxane

1999 ◽  
Vol 65 (5) ◽  
pp. 2276-2278 ◽  
Author(s):  
R. Grümping ◽  
K. Michalke ◽  
A. V. Hirner ◽  
R. Hensel
Keyword(s):  
Molecular Weight ◽  
Sewage Sludge ◽  
Microbial Degradation ◽  
Degradation Product ◽  
Laboratory Experiments ◽  
Low Molecular Weight ◽  
Anaerobic Conditions ◽  
Composted Sewage Sludge ◽  
Control Samples

ABSTRACT The microbial degradation of low-molecular-weight polydimethylsiloxanes was investigated through laboratory experiments. Octamethylcyclotetrasiloxane was found to be biodegraded under anaerobic conditions in composted sewage sludge, as monitored by the occurrence of the main polydimethylsiloxane degradation product, dimethylsilanediol, compared to that found in experiments with sterilized control samples.

scholarly journals Anaerobic degradation of syringic acid by an adapted strain of Rhodopseudomonas palustris

2019 ◽  
Author(s):  
J. Zachary Oshlag ◽  
Yanjun Ma ◽  
Kaitlin Morse ◽  
Brian T. Burger ◽  
Rachelle A. Lemke ◽  
...  
Keyword(s):  
Aromatic Compounds ◽  
Anaerobic Degradation ◽  
Fossil Fuels ◽  
Plant Biomass ◽  
Rhodopseudomonas Palustris ◽  
Reducing Power ◽  
Sole Source ◽  
Syringic Acid ◽  
Detailed Knowledge ◽  
Acid Degradation

ABSTRACTWhile lignin represents a major fraction of the carbon in plant biomass, biological strategies to convert the components of this heterogenous polymer into products of industrial and biotechnological value are lacking. Syringic acid (3,5-dimethoxy-4-hydroxybenzoic acid) is a byproduct of lignin degradation, appearing in lignocellulosic hydrolysates, deconstructed lignin streams, and other agricultural products. Rhodopseudomonas palustris CGA009 is a known degrader of phenolic compounds under photoheterotrophic conditions, via the benzoyl-CoA degradation (BAD) pathway. However, R. palustris CGA009 is reported to be unable to metabolize meta-methoxylated phenolics such as syringic acid. We isolated a strain of R. palustris (strain SA008.1.07), adapted from CGA009, which can grow on syringic acid under photoheterotrophic conditions, utilizing it as a sole source of organic carbon and reducing power. An SA008.1.07 mutant with an inactive benzoyl-CoA reductase structural gene was able to grow on syringic acid, demonstrating that the metabolism of this aromatic compound is not through the BAD pathway. Comparative gene expression analyses of SA008.1.07 implicated the involvement of products of the vanARB operon (rpa3619-rpa3621), which has been described as catalyzing aerobic aromatic ring demethylation in other bacteria, in anaerobic syringic acid degradation. In addition, experiments with a vanARB deletion mutant demonstrated the involvement of the vanARB operon in anaerobic syringic acid degradation. These observations provide new insights into the anaerobic degradation of meta-methoxylated and other aromatics by R. palustris.IMPORTANCELignin is the most abundant aromatic polymer on Earth and a resource that could eventually substitute for fossil fuels as a source of aromatic compounds for industrial and biotechnological applications. Engineering microorganisms for production of aromatic-based biochemicals requires detailed knowledge of metabolic pathways for the degradation of aromatics that are present in lignin. Our isolation and analysis of a Rhodopseudomonas palustris strain capable of syringic acid degradation reveals a previously unknown metabolic route for aromatic degradation in R. palustris. This study highlights several key features of this pathway and sets the stage for a more complete understanding of the microbial metabolic repertoire to metabolize aromatic compounds from lignin and other renewable sources.

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