Biotransformation potential of phytosterols under anoxic and anaerobic conditions

The biotransformation potential of three phytosterols (campesterol, stigmasterol and β-sitosterol) under denitrifying, sulfate-reducing and fermentative/methanogenic conditions was assessed. Using a group contribution method, the standard Gibbs free energy of phytosterols was calculated and used to perform theoretical energetic calculations. The oxidation of phytosterols under aerobic, nitrate-reducing, sulfate-reducing and methanogenic conditions was determined to be energetically feasible. However, using semi-continuously fed cultures maintained at 20–22 °C over 16 weekly feeding cycles (112 days; retention time, 21 days), phytosterol removal was observed under nitrate-reducing and sulfate-reducing conditions, but not under fermentative/methanogenic conditions. Under sulfate-reducing conditions, stigmast-4-en-3-one was identified as an intermediate of phytosterol biotransformation, a reaction more likely carried out by dehydrogenases/isomerases, previously reported to act on cholesterol under both oxic and anoxic (denitrifying) conditions. Further study of the biotransformation of phytosterols under anoxic/anaerobic conditions is necessary to delineate the factors and conditions leading to enhanced phytosterol biodegradation and the development of effective biological treatment systems for the removal of phytosterols from pulp and paper wastewaters and other phytosterol-bearing waste streams.

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Biodegradability of Trimethylbenzene Isomers under Denitrifying and Sulfate-Reducing Conditions

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph16040615 ◽

2019 ◽

Vol 16 (4) ◽

pp. 615 ◽

Cited By ~ 1

Author(s):

Thomas Fichtner ◽

Axel Fischer ◽

Christina Dornack

Keyword(s):

Residence Time ◽

Strong Dependence ◽

Experimental Period ◽

Anaerobic Conditions ◽

Biodegradation Rate ◽

First Order ◽

Sulfate Reducing ◽

Reducing Conditions ◽

Benzene Toluene ◽

Laboratory Investigations

Trimethylbenzene (TMB) isomers (1,2,3-TMB, 1,2,4-TMB, and 1,3,5-TMB) are often used as conservative tracers in anaerobic, contaminated aquifers for assessing BTEX (benzene, toluene, ethylbenzene, xylenes) biodegradation at field sites. However, uncertainties exist about the behavior of these compounds under anaerobic conditions. For this reason, the influence of various parameters (temperature, residence time) on the biodegradability of TMB isomers was investigated under denitrifying and sulfate-reducing conditions in microcosms and 1D-column experiments. Soil and groundwater contaminated with a cocktail of aromatic hydrocarbons including the TMB isomers, both collected from an industrial site in Berlin, Germany, were used for the laboratory investigations. A continuous and complete biodegradation of 1,3,5-TMB and 1,2,4-TMB under denitrifying conditions was observed independent of realized temperature (10–20 °C) and residence time. Biodegradation of 1,2,3-TMB started after longer lag-phases and was not continuous over the whole experimental period; a strong dependence on temperature and residence time was identified. The biodegradability of all TMB isomers under sulfate-reducing conditions was continuous and complete at higher temperatures (20 °C), whereas no degradation was observed for lower temperatures (10 °C). First-order biodegradation rate constants ranged from 0.05 to 0.21 d−1 for 1,3,5-TMB and 1,2,4-TMB and from 0.01 to 0.11 d−1 for 1,2,3-TMB.

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The Use of Seaweed and Sugarcane Bagasse for the Biological Treatment of Metal-contaminated Waters Under Sulfate-reducing Conditions

Biotechnology for Fuels and Chemicals ◽

10.1007/978-1-60327-526-2_44 ◽

2007 ◽

pp. 465-473

Author(s):

Márcia Monteiro Machado Gonçalves ◽

Luiz Antonio Oliveira de Mello ◽

Antonio Carlos Augusto da Costa

Keyword(s):

Sugarcane Bagasse ◽

Biological Treatment ◽

Sulfate Reducing ◽

Reducing Conditions ◽

Contaminated Waters

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The Use of Seaweed and Sugarcane Bagasse for the Biological Treatment of Metal-contaminated Waters Under Sulfate-reducing Conditions

Applied Biochemistry and Biotechnology ◽

10.1007/s12010-007-8091-1 ◽

2007 ◽

Vol 147 (1-3) ◽

pp. 97-105 ◽

Cited By ~ 3

Author(s):

Márcia Monteiro Machado Gonçalves ◽

Luiz Antonio de Oliveira Mello ◽

Antonio Carlos Augusto da Costa

Keyword(s):

Sugarcane Bagasse ◽

Biological Treatment ◽

Sulfate Reducing ◽

Reducing Conditions ◽

Contaminated Waters

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Biodegradation of 2,4,6-trinitrotoluene (TNT) under sulfate and nitrate reducing conditions

Biologia ◽

10.2478/s11756-014-0441-1 ◽

2014 ◽

Vol 69 (10) ◽

Cited By ~ 11

Author(s):

Raj Boopathy

Keyword(s):

Contaminated Soil ◽

Anaerobic Degradation ◽

Sole Source ◽

Soil Samples ◽

Anaerobic Conditions ◽

Soil Slurry ◽

Sulfate Reducing ◽

Metabolic Analysis ◽

Reducing Conditions ◽

Metabolic Conditions

AbstractAnaerobic degradation of 2,4,6-trinitrotoluene (TNT) was studied under sulfate- and nitrate-reducing conditions using enrichment cultures developed from a TNT-contaminated soil from the Louisiana Army Ammunition Plant (LAAP) in Minden, Louisiana, USA. The soil samples were enriched using mineral salt media with either nitrate or sulfate as electron acceptors in the presence of TNT under strict anaerobic conditions. The enriched samples were experimented with TNT as either the sole source of carbon or nitrogen and also under co-metabolic conditions with molasses as co-substrate. The results revealed that TNT was removed under both electron acceptor conditions. However, the TNT degradation efficiency was significantly higher under sulfate-reducing conditions than the nitrate-reducing conditions. Under sulfate-reducing conditions, TNT removal was faster when molasses was used as co-substrate. The metabolic analysis showed that TNT was mineralized and the major end product was acetic acid, CO2, and ammonia. A soil slurry reactor with TNT-contaminated soil showed more than 90% of TNT removal within 60 days of incubation.

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Faculty Opinions recommendation of Comparison of mechanisms of alkane metabolism under sulfate-reducing conditions among two bacterial isolates and a bacterial consortium.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1001941.375085 ◽

2006 ◽

Author(s):

Peter Williams

Keyword(s):

Bacterial Consortium ◽

Bacterial Isolates ◽

Sulfate Reducing ◽

Reducing Conditions

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Cadmium sorption by EPSs produced by anaerobic sludge under sulfate-reducing conditions

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2006.05.092 ◽

2006 ◽

Vol 138 (3) ◽

pp. 589-593 ◽

Cited By ~ 83

Author(s):

Daoyong Zhang ◽

Jianlong Wang ◽

Xiangliang Pan

Keyword(s):

Anaerobic Sludge ◽

Sulfate Reducing ◽

Reducing Conditions

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Profiling of human burned bones: oxidising versus reducing conditions

Scientific Reports ◽

10.1038/s41598-020-80462-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

M. P. M. Marques ◽

D. Gonçalves ◽

A. P. Mamede ◽

T. Coutinho ◽

E. Cunha ◽

...

Keyword(s):

Inelastic Neutron Scattering ◽

Inelastic Neutron ◽

Skeletal Remains ◽

Anaerobic Conditions ◽

Human Skeletal Remains ◽

Human Bones ◽

Reducing Conditions ◽

Wide Range ◽

Burned Bones ◽

Vibrational Bands

AbstractComplementary optical and neutron-based vibrational spectroscopy techniques (Infrared, Raman and inelastic neutron scattering) were applied to the study of human bones (femur and humerus) burned simultaneously under either aerobic or anaerobic conditions, in a wide range of temperatures (400 to 1000 °C). This is the first INS study of human skeletal remains heated in an oxygen-deprived atmosphere. Clear differences were observed between both types of samples, namely the absence of hydroxyapatite’s OH vibrational bands in bone burned anaerobically (in unsealed containers), coupled to the presence of cyanamide (NCNH2) and portlandite (Ca(OH)2) in these reductive conditions. These results are expected to allow a better understanding of the heat effect on bone´s constituents in distinct environmental settings, thus contributing for an accurate characterisation of both forensic and archaeological human skeletal remains found in distinct scenarios regarding oxygen availability.

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