Anaerobic Microbial Degradation Research Articles

Genesis of Indian Tertiary coals and lignites: a biopetrological and palaeobotanical view point

Coal and lignite seams associated with the Tertiary sedimentary sequence of India are bright unbanded (coals) and sparingly banded (lignites) in appearance. They chiefly consist of vitrinite/huminite macerals with subordinate amounts of liptinites and inertinites. Desmocollinite/attrinite and densinite are the main vitrinite/huminite maceral groups. Sclerotinite (fungal remains) and inertodetrinite are the main inertinite macerals in the seams of northeastern States-Tamil Nadu, Rajasthan and Gujarat. Some of the coal and lignite seams of Meghalaya and Gujarat have predominance of structured inertinite macerals (semifusinite and fusinite). Main inorganics associated with the seams are syngenetic pyrite and calcite. Clay and quartz (argillaceous matter) are usually in low proportions except in certain seams of Gujarat and Meghalaya. The seams, under blue light excitation, are characterized by moderate to very high proportion of fluorescing macerals constituted chiefly by perhydrous vitrinite/huminite, liptodetrinite, bituminite and resinite. Other macerals of liptinite group, viz., cutinite, sporinite, suberinite, exsudatinite, alginite (Botryococcus) and fluorinite in order of decreasing abundance, are in subordinate amounts.
 The coal and lignite-forming evergreen angiospermous forest vegetation flourishing under humid tropical climate comprised inland, coastal, beach, back mangrove to mangrove plant communities. Herbaceous and shrubby, including aquatic, angiosperms and pteridophytes formed prolific undergrowth. Some of the coal and lignite seams of Meghalaya, Rajasthan and Gujarat have definite marine and brackish water elements.
 The Tertiary coal and lignite deposits of India originated from hypo-autochthonous to autochthonous rheotrophic peat accumulating in lagoons or near-shore back swamps in Assam, Nagaland, Tamil Nadu, Rajasthan and Gujarat and in small isolated estuarine or estuarine back swamps in Meghalaya. The vegetal matter experienced both aerobic and anaerobic microbial degradation under neutral to mildly alkaline subaqueous conditions. The coalification trends of the ancient peat were influenced more by putrefaction rather than purily by humification. Small and ephemeral fresh water ponds/lakes developed occasionally on peat surface were responsible for the presence of aquatic and water-edge taxa in the seams. Herbaceous and shrubby vegetation, especially pteridophytes, growing in the vicinity of ancient peat swamps were the main source of structured and detrital inertinites. Occasional natural cindering of the peat surface, e.g., in Gujarat and Meghalaya, was responsible for relatively high inertinite contents. Variations in the thickness and rank of coal and lignite seams were controlled by the existing tectonic conditions and geothermal gradients in different areas.
 Keywords- Biopetrology, Coal and lignite genesis, Palaeoenvironment, India.

Tertiary coals of Makum Coalfield, Assam, India: Petrography, genesis and sedimentation

The two most important coal seams, viz., Seam no. 1 (18 m thick) and Seam no. 3 (6 m thick), of the Tikak Parbat Formation, Barail Group (Oligocene) are overlain by > 2000 m thick sediments of younger age. The coals are bright and non-banded in appearance. They are rich in vitrinite with subordinate amounts of liptinite and inertinite macerals. Early diagenetic pyrite and calcite alongwith clay and quartz are the main associated minerals. Under blue light excitation high amount of fluorescing macerals recorded are formed chiefly by perhydrous Vitrinite, liptodetrinite and resinite. Minor amount of sporinite, cutinite, suberinite and exsudatinite are also present with sporadic occurrence of f1uorinite and alginite. A comparison of Makum coals with the other Tertiary coals of India has also been attempted. The coals have low moisture and ash contents with high volatile matter and calorific value in relation to their rank by reflectivity measurements. The rank of the coal seams (R0 max. 0.72-0.75%) corresponds to high volatile bituminous B stage.
 From the biopetrological, palaeobotanical and geological evidences it has been concluded that the coal seams originated mostly from in situ mangrove-mixed angiospermous forest vegetation growing under humid to per-humid tropical climate. The vegetal accumulation took place in a rheotrophic swamp forming in a near-shore lagoon on a lower delta plain. The maceral and mineral associations in the coal seams indicate that the accumulated vegetal matter was mainly subjected to anaerobic microbial degradation under elevated swamp water pH (> 6). This facilitated the precipitation of early diagenetic pyrite, calcite and in situ release of plant-derived minerals in the peat. Under these conditions highly pyriteous and perhydrous coal seams were formed mainly by putrefaction. Whenever microbial degradation of organic matter was severe normal vegetal supply fell short to produce a peat layer, with the result minor and major authigenic partings within the coal seams were formed.

Anaerobic microbial degradation of acridine and the application of remote fiber spectroscopy to monitor the transformation process

Anaerobic microbial transformation of a polynuclear nitrogen heterocycle, acridine, was studied in laboratory microcosms with three different inocula: a stabilized, mixed culture growing on ferulic acid that was originally enriched from anaerobic sewage sludge, and sulfate-reducing and methanogenic aquifer materials from two sites at a groundwater aquifer contaminated by landfill leachate. Acridine degradation was investigated under methanogenic, denitrifying and sulfate-reducing conditions at concentrations of 1 to 6 μg/ml. Substrate degradation was followed using two standard analytical techniques (HPLC and GC-MS) and a new, in situ remote fiber spectroscopic (RFS) technique. This RFS was used successfully to follow changes in concentration of acridine with time, which indicates the technique has a significant potential for monitoring the degradation process in environmental media. Acridine was degraded extensively in one to three weeks under each of the conditions studied. A range of heterocyclic, homocyclic aromatic and aliphatic intermediates was identified by GC-MS analyses. On the basis of these compounds, a tentative route of anaerobic acridine transformation is proposed that begins with oxidation and proceeds through the common degradative route for oxidized aromatic compounds.

Petroleum and Chlorinated Hydrocarbon Analysis in Support of In Vitro Studies of Natural Anaerobic and Aerobic Microbial Degradation of Xenobiotics in Contaminated Groundwater and Soil

Abstract This program investigated in situ biological degradation as a remedial treatment technique at a United States Air Force Base in Texas. Soil and groundwater samples from the site were characterized regarding microbial populations and presence or absence of priority pollutant xenobiotics and petroleum hydrocarbon components. Time-series analyses of replicate nutrient-amended microcosms after approximately 1, 25, 50 and 100 days permitted aerobic and anaerobic degradation rate evaluation. Microcosm integrity was demonstrated throughout the experiment by observing appropriate dissolved oxygen, pH, oxidation/reduction potential, and sterile/viable conditions. Gas chromatographic analysis and ratios of straight-chain and isoprenoid components clearly demonstrated that aerobic conditions were preferred for degradation of aliphatic and aromatic petroleum hydrocarbons. Electron capture gas chromatographic analyses and purge-and-trap gas chromatographic/mass spectrometric analyses of lower molecular weight...

Biology of anaerobic microorganisms

Geochemistry and Biogeochemistry of Anaerobic Habitats (A. Zehnder & W. Stumm). Microbiology, Physiology, and Ecology of Phototrophic Bacteria (M. Madigan). Molecular Mechanisms of Bacterial Photosynthesis (J. Amesz & D. Knaff). Ecology of Denitrification and Dissimilatory Nitrate Reduction to Ammonium (J. Tiedje). Dissimilatory Reduction of Oxidized Nitrogen Compounds (A. Stouthamer). Microbial Reduction of Manganese and Iron (W. Ghiorse). Anaerobic Microbial Degradation of Cellulose, Lignin, Oligolignols, and Monoaromatic Lignin Derivatives (P. Colberg). Anaerobic Hydrolosis and Fermentation of Fats and Proteins (M. McInerney). Acetogenesis (J. Dolfing). Microbiology and Ecology of Sulfate- and Sulfur-Reducing Bacteria (F. Widdel). Dissimilatory Reduction of Sulfur Compounds (J. LeGall & G. Fauque). Biogeochemistry of Methanogenic Bacteria (R. Oremland). Biochemistry of Methane Production (G. Vogels, et al.). Principles and Limits of Anaerobic Degradation: Environmental and Technological Aspects (B. Schink). Index.

Microbial degradation by the autochthonous soil population of alpha and beta HCH under anaerobic field conditions in temperate regions

Microbial soil sanitation technology was applied to calcareous, alkaline, sandy loam soil, polluted with a mixture of hexachlorocyclohexane isomers (alpha 400; beta 230; gamma 15 and delta 17 mg·kg −1). Under anaerobic conditions microbial degradation in the Dutch climate (soil temperature 5–17°C) failed, and even the low concentration of the easily degradable gamma HCH failed to be affected. The well homogenized soil contained a normal number of bacteria and in the laboratory (at 9 and 20°C) proved to possess a sanitation potential for alpha HCH, the main pollutant. The open literature mainly refers to anaerobic degradation of low concentrations of gamma and alpha HCH, though sometimes also to that of beta HCH. For degrading higher concentrations (>400 mg·kg −1) in lower temperature regions aerobic soil conditions are preferable. It was concluded that the failure of microbial sanitation in the field was due to combined environmental conditions of anaerobic soil plus low soil temperature.

Recent Developments in Process and Reactor Design for Anaerobic Wastewater Treatment

There are a large number of advantages in using microbial anaerobic degradation processes in wastewater pretreatment. However, a disadvantage of this method is the relatively long doubling times of anaerobic microorganisms. Because of the autocatalytic nature of the microbial processes and the low carbon incorporation rate which results in low biomass concentrations in continuously operated systems, decoupling of the residence times for substrate and biomass in necessary. In this way, high volume time yields of biogas can be achieved under anaerobic conditions. From the well known methods for achieving biomass retention, immobilization on inert support media is thought to be an effective alternative. Experiments on anaerobic treatment of sulfite evaporator condensate using immobilized microorganisms were carried out in a 12 1 fixed bed loop reactor. Porous sintered glass with a porosity of about 50% and a mean pore diameter of 60-100 µm served as the media. The reactor was operated for several months under steady state conditions at different residence times. At a residence time of 11 h, 84% of the COD was removed at loading rates up to 100 kg COD.m3.day. By optimization of porosity and pore size distribution a further improvement in the volume time yield of biogas was possible. Using reticulated sintered glass with a porosity of 60% and a pore size distribution of 60-300 µm, COD removal rates up to 160 kg/m3.d could be obtained. Experiments are currently being carried out with a pilot plant (reactor volume of 1.0 m3). This is necessary to obtain the characteristics necessary for scale up and calculating the economic viability of the process.

Anaerobic microbial degradation of selected 3,4-dihalogenated aromatic compounds

Anaerobic microbial degradation of selected 3,4-dihalogenated aromatic compounds was studied in medium inoculated with pond sediment. Sediment samples were collected from a diuron-treated pond. Diuron was dehalogenated at the para position, forming CPDMU as the sole degradation product. DCPU was similarly dehalogenated at the para position, forming MCPU as the only degradation product. Linuron degradation resulted in four products: one, CPMMU, was the result of biological dehalogenation at the para position; another, DCPMU, was the result of chemical degradation; and the other two products were unidentified. Chlorbromuron degradation formed three unidentified products. Stam, an acylanilide, was degraded, forming two products, one of which was possibly 3-chloropropioanilide. CIPC and an unidentified compound were formed from DCIP. No degradation of parent compounds or appearance of degradation products were detected in mixtures of each test compound and sterile sediment except linuron.

Anaerobic Treatment of Sulfite Evaporator Condensate in a Fixed Bed Loop Reactor

There are a large number of advantages in using microbial anaerobic degradation processes in waste water pretreatment. A disadvantage of this method lies in the relatively long doubling times of anaerobic microorganisms which cause long residence times in a continuous stirred tank reactor. Because of the autocatalytic behaviour of the microbial processes and the low carbon incorporation rate which results in low biomass concentrations, decoupling of residence times for substrate and biomass in continuously operated systems is necessary. In this way high space time yields can be achieved under anaerobic conditions as well. From the well known variants for biomass retention, immobilisation by an inert support is thought to be an effective alternative. Experiments on anaerobic treatment of sulfite evaporator condensate by means of immobilized microorganisms were carried out in a 121-fixed bed loop reactor. Porous sinter glass from SCHOTT Mainz with a porosity of about 60 % and a mean pore diameter of 60-100 μm served as carrier. The reactor was operated for several months under steady state conditions at different residence times using an iterative approach. At a residence time of 11 h 84 % of the chemical oxygen demand (COD) was eliminated at loading rates up to 100 kg COD/m3 and day. Online data acquisition and process control are recommended and easily realized by means of a digital computer, in order to increase selection stress on microorganism population and optimize space time yield.

Anaerobic microbial degradation of diuron by pond sediment

Anaerobic degradation of the herbicide diuron, 3-(3,4-dichlorophenyl-1,1)dimethylurea, was studied. Enrichment cultures were established with seven different media in the presence of diuron (40 mg/liter). Media included combinations of sediment extract, mineral salts, and various organic amendments. Cultures were inoculated with aliquots of sediment collected from a pond previously treated with diuron and were maintained under an atmosphere of 95% N 2 and 5% CO 2. All enrichment cultures completely degraded diuron in 17–25 days. In all cultures showing diuron degradation, the product identified as 3-(3-chlorophenyl)-1,1-dimethylurea appeared in approximately stoichiometric amounts. Reinjection of diuron into each culture after 26 days resulted in rapid degradation of the parent herbicide with the appearance of proportionately more 3-(3-chlorophenyl)-1,1-dimethylurea. No other product was detected after 80 days in culture and the metachloro derivative was not degraded further during this time.

Origin of objectionable odorous components in piggery wastes and the possibility of applying indicator components for studying odour development

Many problems are associated with the measurement of objectionable odours from livestock confinement buildings. In principle, odours can be measured only by using techniques which include the human nose. But sensorial techniques have many disadvantages for routine purposes. As an alternative approach many authors have tried to determine odour intensity by measuring the concentration of one or more of the volatile constituents of odorous air. The choice of the compounds to be measured in such an approach is very important. In piggery wastes about 150 volatile compounds have been identified. Most of these compounds are presumed to be products of anaerobic microbial degradation of the waste constituents. The microbial pathways leading to the formation of the various volatile compounds in the wastes are indicated in this paper. In addition, the overall process of the conversion of high molecular waste constituents to low molecular weight compounds is discussed. Finally, it is suggested that certain volatile waste constituents, which are strongly related to the degradation of protein and/or plant fibre residues, are suitable for monitoring instrumentally. It is concluded that p-cresol and volatile fatty acids to a large extent meet the requirements for such indicator compounds.