Strong Bacterial Activity Research Articles

Кварцевые песчаники сосновской толщи палеогена Ульяновско-Сызранского Поволжья (восток Русской плиты): вещественный состав и происхождение

The Paleogene quartz sandstones of the Sosnovka formation are widely occurred in the Uljanovsk-Syzran Volga region and are used as valuable building materials. The articlecomprises an improvement for thecontinental origin of the Sosnovkasandstones based on the results of a comprehensive study of the features of the mineral composition and microstructure of quartz sandstones of the Sosnovka formation obtained by using petrographic, XRD and electron-microscopic analyses. Therelevance of thestudy is based on the debatability of the origin ofsandstones, the depletion ofthemineralresource base ofthistype ofmineralrawmaterials andthe needto develop new approachesto its prediction. Accordingto theresults ofthestudy, itwasfoundthat opokas and diatomites ofthe Lower Syzransubformation, brought uptothe denudationsurface,could be the source of free silica for the cementation of sand grains of the Sosnovka sandstones. The deficit of siliceous cement and its extremely irregular distribution among the clastic grains indicate the local and restrict occurance of the source of solutions saturated with free silica, which, most likely, was controlled by paleorelief. Electron microscopic images and microprobe analysis of individual sandstone microcomponents indicate strong bacterial activity and frequent change of the land paleoenvironments to extensive marshy ones. The formation of pyrite framboids in the cementitious mass is a sign of oxygen deficit in the continental basin and the activity of magnetotactic bacteria. Whereas the decay of framboids is associated with dissolution of organic matter inside the framboids due to oxidation of the paleobasin. The results of the study leave no doubt about the non-marine origin of the sandstones studied, hence, we should not assume the presence of extended bodies of sustained thickness when solving prognostic-mineralogical problems. The Sosnovka sandstones are of extremely irregular distribution in the sandy sequence and formation in extremely continental pedological conditions will allow us to solve the important task of improving approaches to the prediction of new objects of this valuable mineral resource in the Ulyanovsk-Syzran Volga region.

Secondary Minerals from Minothem Environments in Fragnè Mine (Turin, Italy): Preliminary Results

The Fragnè mine, located in the Lanzo valley in the municipality of Chialamberto (Turin, Piedmont Region), represented the most important regional site for Fe–Cu sulfide exploitation over a period of more than eighty years (1884–1965). The entire mining area is part of a structural complex in the Lower Piedmont Unit of the Western Alps, characterized by the presence of amphibolite, metabasite (“prasinite”), and metagabbroic rocks. In particular, the pyrite ore deposit occurs as massive mineralizations within interlayered metabasites and amphibolites. In this work, we describe secondary minerals and morphologies of minothems from the Fragnè mine that are found only in abandoned underground works, such as soda straws, normal and jelly stalactites and stalagmites, jellystones, columns, crusts, blisters, war-clubs, and hair, characterized by different mineralogical associations. All minothems were characterized by minerals formed during acid mine drainage (AMD) processes. Blisters are composed only of schwertmannite, war-clubs by schwertmannite, and goethite with low crystallinity and hair by epsomite and hexahydrite minerals. Jelly stalactites and stalagmites are characterized by schwertmannite often in association with bacteria, while solid stalactites and stalagmites are characterized by jarosite and goethite. The results indicate that the mineralogical transformation from schwertmannite to goethite observed in some minothems is probably due to aging processes of schwertmannite or local pH variations due to bacterial activity. On the basis of these results, we hypothesize that all the jelly samples, in association with strong bacterial activity, are slowly transformed into more solid goethite, and are thus precursors of goethite stalactites.

UJI AKTIVITAS ANTIBAKTERI EKSTRAK KULIT BUAH KAWISTA (LIMONIA ACIDISSIMA) TERHADAP ESCHERICHIA COLI

Escherichia coli is a normal bacteria lives in the large intestine to help the process and maintain human digestive health. However, there are certain types of Escherichia coli which are pathogenic to human body and cause infections, such as diarrhea, urinary tract infections, meningitis, sepsis and so on. Irrational use of antibiotics leads to bacterial resistance to antibiotics. Kawista is one of the fruits that used as traditional medicine in Indonesia. Kawista peel extract can be used as an alternative therapy to prevent resistance. Based on the content of secondary metabolites, kawista peel extract is thought to have antibacterial activity. The purpose of this study was to determine the antibacterial activity of kawista (Limonia accidisima) peel extract against Escherichia coli. This research is an in-vitro study, preceded by a phytochemical screening test for methanol extract of kawista peel, then followed by an antibacterial activity test using the disc diffusion method and determining the minimum inhibitory concentration (MIC). The results showed that the kawista peel extract contained secondary metabolites such as alkaloids, flavonoids, saponins, tannins and terpenoids which have antibacterial activity. The concentration of the extract is directly proportional to its antibacterial activity. The 5% extract concentration gave an average inhibition zone diameter of 8.81 mm (moderate antibacterial activity), while at the 80% extract concentration the average inhibition zone diameter was 22.71 mm (very strong bacterial activity). Kawista peel extract (Limonia acidissima) has antibacterial activity with a minimum inhibitory concentration of 5%. Keywords: Antibacterial, Kawista, Limonia acidissima, Escherichia coli

Depositional environment and hydrocarbon potential of the Oligocene Menilite Formation in the Western Carpathians: A case study from the Loučka section (Czech Republic)

Abstract The Eocene-Oligocene boundary in the Paratethys area represents a period associated with a major extinction event followed by anoxic events. A good understanding of the factors controlling the formation of organic-rich layers is a key for prediction of source rock distributions. An excellent opportunity to study these factors is provided by the Loucka section situated in the Silesian Unit of the Czech Republic. The Menilite Formation is subdivided into the Subchert Member, Chert Member, Dynow Marlstone and Sitbořice Member and comprises non-calcareous shales, marlstones and cherts. The lithological variations reflect strongly depositional environment, which caused strong changes in geochemical parameters and source rock potential. The ratio of total organic carbon to total sulphur (TOC/TS) and methylated 2-methyl-2 (trimethyltridecyl) chroman (MTTC) ratios supported by paleontological evidence show normal marine to brackish water conditions. Pr/Ph ratios indicate strictly anoxic conditions during deposition of the upper part of the Subchert Member and the lower part of the Chert Member. Very low steranes/hopanes ratios reflect strong bacterial activity during deposition of the Chert Member. Very high HI values (>600 mg HC/g TOC) and the apparent absence of terrestrial macerals suggest that high amounts of C29 steranes and long-chain n-alkanes in this member result from the input of algal material. The Menilite Formation contains mainly type II kerogen and typically holds a “good” source rock potential. HI values > 600 mg HC/g TOC are observed in the Chert Member, while values The source potential index (SPI) of the entire succession of the Menilite Formation is about 1.25 t HC/m2, which is significantly lower than SPI determined for the Polish and Ukrainian Carpathians, but mainly due to the lower thickness.

Sources of organic matter for bacteria in sediments of Lake Rotsee, Switzerland

Determination of carbon sources and microbial activity in lake sediment is important for understanding organic carbon preservation and methane production. This study aimed to determine the organic carbon sources and microbial activity over the last 140 years in sediments of methanotrophic Lake Rotsee (Switzerland). We investigated phospholipid-derived fatty acid biomarkers and their stable carbon isotope signatures in the sediments of this eutrophic lake. Strong bacterial activity in the sediment deposited during the 1920s–1960s could account for the relatively low ratio of long-chain to short-chain fatty acid ((C24 + C26 + C28)/(C14 + C16 + C18), TARFA) values, which is consistent with low TOC/TN ratios in the sediment deposited during that interval. The carbon stable isotope records, both bulk and compound-specific, showed greater values at such times, although the offset between the bulk and fatty acids decreased. This implies that the microbial community residing at sediment depths deposited in the 1960s preferentially utilised the compounds derived from the enhanced surface-water productivity at that time. This observation contrasts with data from the depth intervals before and after, when a major portion of the labile organic matter was derived from methane-sourced production. In sediments deposited before ca. 1964, the overall very low fatty acid δ13C values suggest that labile carbon was primarily derived from methanotrophs.

Synthesis, Antibacterial Activity, Interaction with Nucleobase and Molecular Docking Studies of 4-Formylbenzoic Acid Based Thiazoles.

Synthesis, characterization and investigation of antibacterial activity of ten novel Schiff base derivatives of 4-formylbenzoic acid is presented. Their structures were determined using 1H and 13CNMR, EI(+)-MS and elemental analyses. Additionally, DFT calculations of interaction energies in complexes of the novel drugs and DNA bases are carried out. Design and synthesis of thiazole derivatives with benzoic acid scaffold to obtain compounds with an improved antibacterial activity. The examined compounds were screened in vitro for antibacterial activity using the broth microdilution method. Geometrical parameters of the investigated complexes were optimized within the Density Functional Theory (DFT) approximation using the B3LYP functional and the 6-311G** basis set. The docking simulations were performed using the FlexX docking module. Among the derivatives, compound 4b showed very strong bacterial activity against staphylococci, MIC 1.95-3.91 µg/ml, micrococci, MIC 0.98 µg/ml, and Bacillus spp., MIC 7.81-15.62 µg/ml. The compounds 4c, 4d, 4e and 4j also showed high bioactivity against staphylococci, MIC 3.91-31.25 µg/ml, and micrococci, MIC 0.98-15.62 µg/ml. Interaction energy values for investigated guanine complexes are about 2 kcal/mol lower than for the corresponding cytosine complexes. Molecular docking studies of all compounds on the active sites of bacterial enzymes indicated gyrase B as possible target. To conclude, an efficient and economic method for the synthesis of thiazoles containing benzoic acid moiety has been developed. The results of antibacterial screenings reveal that some obtained compounds show high to very strong antibacterial activity. The DFT calculations showed that interaction of the obtained drugs with guanine is stronger than with cytosine. Molecular docking studies of all compounds on the active sites of bacterial enzymes indicated gyrase B as possible target.

In situ monitoring of lepidocrocite bioreduction and magnetite formation by reflection Mossbauer spectroscopy

The miniaturized Mössbauer spectrometer (MIMOS II) was used to monitor in situ the mineralogical transformation of lepidocrocite (γ-FeOOH) in a Shewanella putrefaciens culture under anaerobic conditions using methanoate as the electron source. Magnetite was the only biogenic mineral formed during the course of the incubation. The analysis of the biogenic mineral by transmission electron microscopy (TEM) revealed cubic-shaped crystals with a relatively homogeneous grain size of about 50 nm. After one day of incubation, the departure from stoichiometry, δ, of the biogenerated magnetite was very low (δ ~ 0.025) and rapidly reached values close to zero. Such low values of δ were not obtained for magnetite synthesized inorganically when Fe3+ in the form of γ-FeOOH was reacted with stoichiometric quantities of soluble Fe2+ and OH-. The experimental setup used in this study could be replicated in field experiments when assessing the formation of magnetite in modern geological settings as its formation is suspected to be caused by a strong bacterial activity.

06/01496 Sequential fatty acid analysis of a peat core covering the last two millennia (Tritrivakely lake, Madagascar): Diagenesis appraisal and consequences for palaeoenvironmental reconstruction: Disnar, J.-R. et al. Organic Geochemistry, 2005, 36, (10), 1391–1404

The genesis of the microscopic constituents of coal (macerals) and of maceral associations (microlithotypes) representing various coal facies is discussed in the light of recent advances that have been made in the study of coals and modern peats. Peat microscopy especially promoted the understanding of humification and biological gelification, both of which are decisive for the genesis of huminites/vitrinites in brown coals and hard coals, respectively. Microbial activity during peatification has been documented by chemists, microbiologists and petrologists and, recently, by electron-microscopical observations in coals. This activity leads to the incorporation of lipid substances into the humic matter and, later, influences the chemical, physical and technological properties of vitrinites. Geochemical gelification transforms the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal. In this process, the hydrogel brown coal is transformed to the bitumogel bituminous coal. Coal as a source rock for oil has become an important research subject for coal petrologists and oil exploration. The formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to the “coalification jumps” of the macerals, especially liptinites and vitrinites and to the generation of secondary macerals like exsudatinite (bitumen) and micrinite (dead carbon). Bituminization in coal has been revealed by the use of fluorescence microscopy which also found the presence of new liptinite macerals (bituminite, fluorinite and exsudatinite) and suggests a higher proportion of algal material in coals than was thought earlier. The genesis of various types of inertinite macerals will probably become an increasingly important subject of research, especially with regard to “rank-inertinites” that seem to attain their high inertinitic reflectance initially during coalification.Besides the origin of macerals, the origin of various coal facies in terms of maceral associations is considered in relation to the palaeogeographic depositional milieu, the peat-forming vegetation, palaeoclimate, water and nutrient supply, acidity, marine and calcareous influence and fire, with examples from Euramerican Carboniferous coals, Gondwana coals, and Tertiary brown coals. Vegetation, water and oxygen supply (Eh-conditions) are most important for the generation of coal facies.Vegetation has been reconstructed with the help of palaeobotany, including palynology, cuticular analysis and wood anatomy (in brown coals) and with the study of petrified (permineralized) peats preserved in coal balls. The microscopical investigations of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative. However, the results of palynological and cuticular analyses should be evaluated with caution, considering the varying resistance of palynomorphs and cuticles and, in the case of palynomorphs, their possible extrapaludal origin.Microscopical studies of modern peats that were derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies, especially in brown coals. The much disputed origin of brown-coal lithotypes is considered in detail. For hard coals there seems to be agreement that coal layers rich in vitrites and liptinite-poor clarite were deposited in wet-forest swamps, that microlayered liptinite-rich clarites are sub-aquatic humic muds, and that inertinite-rich durites represent oxidized peats. The origin of liptinite-rich durites is controversial (either subaquatic muds or oxidized peats, the latter perhaps from raised bogs).A recent trend in the literature is the assumption that many if not all mineable coal seams have been deposited in raised bogs under ombrogenous, oligotrophic conditions. Although raised bogs with a dense arborescent vegetation are known from Borneo, it seems not probable that most seams (which were deposited in foredeeps or steadily sinking graben zones) are of ombrogenous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for occasional seams. But, as in modern peats, striking changes of coal facies are commonly caused by hydrological events, e.g., inundations as a consequences of crevasses or of fires that burned the peat.The origin of the inertinite-rich Gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub-arctic peats is recommended.Coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite, as well as by hydrogen-rich vitrinites with a relatively low reflectance and high fluorescence, all due to a strong bacterial activity in peats of low acidity.Proposals for further research are made in the conclusions.

05/00548 Studies of the coal facies in Western Ukraine (the Lvov-Volyn basin)

The genesis of the microscopic constituents of coal (macerals) and of maceral associations (microlithotypes) representing various coal facies is discussed in the light of recent advances that have been made in the study of coals and modern peats. Peat microscopy especially promoted the understanding of humification and biological gelification, both of which are decisive for the genesis of huminites/vitrinites in brown coals and hard coals, respectively. Microbial activity during peatification has been documented by chemists, microbiologists and petrologists and, recently, by electron-microscopical observations in coals. This activity leads to the incorporation of lipid substances into the humic matter and, later, influences the chemical, physical and technological properties of vitrinites. Geochemical gelification transforms the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal. In this process, the hydrogel brown coal is transformed to the bitumogel bituminous coal. Coal as a source rock for oil has become an important research subject for coal petrologists and oil exploration. The formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to the “coalification jumps” of the macerals, especially liptinites and vitrinites and to the generation of secondary macerals like exsudatinite (bitumen) and micrinite (dead carbon). Bituminization in coal has been revealed by the use of fluorescence microscopy which also found the presence of new liptinite macerals (bituminite, fluorinite and exsudatinite) and suggests a higher proportion of algal material in coals than was thought earlier. The genesis of various types of inertinite macerals will probably become an increasingly important subject of research, especially with regard to “rank-inertinites” that seem to attain their high inertinitic reflectance initially during coalification.Besides the origin of macerals, the origin of various coal facies in terms of maceral associations is considered in relation to the palaeogeographic depositional milieu, the peat-forming vegetation, palaeoclimate, water and nutrient supply, acidity, marine and calcareous influence and fire, with examples from Euramerican Carboniferous coals, Gondwana coals, and Tertiary brown coals. Vegetation, water and oxygen supply (Eh-conditions) are most important for the generation of coal facies.Vegetation has been reconstructed with the help of palaeobotany, including palynology, cuticular analysis and wood anatomy (in brown coals) and with the study of petrified (permineralized) peats preserved in coal balls. The microscopical investigations of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative. However, the results of palynological and cuticular analyses should be evaluated with caution, considering the varying resistance of palynomorphs and cuticles and, in the case of palynomorphs, their possible extrapaludal origin.Microscopical studies of modern peats that were derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies, especially in brown coals. The much disputed origin of brown-coal lithotypes is considered in detail. For hard coals there seems to be agreement that coal layers rich in vitrites and liptinite-poor clarite were deposited in wet-forest swamps, that microlayered liptinite-rich clarites are sub-aquatic humic muds, and that inertinite-rich durites represent oxidized peats. The origin of liptinite-rich durites is controversial (either subaquatic muds or oxidized peats, the latter perhaps from raised bogs).A recent trend in the literature is the assumption that many if not all mineable coal seams have been deposited in raised bogs under ombrogenous, oligotrophic conditions. Although raised bogs with a dense arborescent vegetation are known from Borneo, it seems not probable that most seams (which were deposited in foredeeps or steadily sinking graben zones) are of ombrogenous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for occasional seams. But, as in modern peats, striking changes of coal facies are commonly caused by hydrological events, e.g., inundations as a consequences of crevasses or of fires that burned the peat.The origin of the inertinite-rich Gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub-arctic peats is recommended.Coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite, as well as by hydrogen-rich vitrinites with a relatively low reflectance and high fluorescence, all due to a strong bacterial activity in peats of low acidity.Proposals for further research are made in the conclusions.

Molecular organic geochemical peculiarities of lacustrine core sediments in Fildes Peninsula, King George Island, Antarctica

The peculiarities of lipids in lacustrine core sediments from Fildes Peninsula, King George Island, Antarctica, are reported. The origin of high-molecular-weight n-alkanes, alkenes, fatty acids, alcohols Is supposed to be related to the abundant moss occurring in the sediments. Abundantiso- andanteiso-fatty acids that occur in the sediments indicate a relatively strong bacterial activity in non-ice-cover zone than in other regions in Antarctica. The C18:2 unsaturated fatty acids mainly originate from autochthonous algae in the sediment pool, and the C18:2C18:0 ratios in the profile are controlled more by paleotemperatures than source assemblies. Long-chain alkenones were identified in freshwater lacustrine sediment in Antarctica for the first time, of whichPrymnesiophyceae is assumed to be the source organism. High relative abundance of C37:4 homologue in long-chain alkenone well correlates to the severely cold climate in Antarctica.

99/00019 Coprocessing Yanzhou coal with petroleum residue

The genesis of the microscopic constituents of coal (macerals) and of maceral associations (microlithotypes) representing various coal components is discussed in light of recent advances that have been made in the study of coals and modern peats. Peat microscopy especially promoted the understanding of humification and biological gelification, both of which are decisive for the genesis of huminities/vitrinites in brown coals and hard coals, respectively. Microbial activity during peatification has been testified by chemists, microbiologists, and petrologists, and also recently by electron-microscopical observations matter and later, influences the chemical, physical and technological properties of vitrinites. Geochemical gelification transform the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal. In this process, the hydrogel brown coal is transformed to the bitumogel bituminous coal. “Coal as a source rock for oil” has become an important research subject for coal petrologists (and oil exploration!). The formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to “coalification jumps” of the macerals, especially liptinite and vitrinites and to the generation of secondary macerals like exsudatinite (bitumen) and micrinite (dead carbon). Bituminization in coal has been revealed by the use of fluorescence microscopy that also showed the presence of new liptinite macerals (bituminite, fluorinite and exsudatinite) and suggests a higher proportion of algal material in coals than was thought earlier. The genesis of various inertinites will probably become an increasingly important subject of research, especially with regard to “rankinertinites” which seem to attain their high inertinitic reflectance during early coalification.Besides the origin of macerals, the origin of various coal facies in terms of maceral associations is considered in relation to the paleogeographic depositional milieu, the peat-forming vegetation, paleoclimate, water and nutrient supply, acidity, marine and calcareous influence, and fire, with examples from Euramerican Carboniferous coals, Gondwana coals and Tertiary brown coals. Vegetation and water and oxygen supply (Eh-conditions) are most important for the formation of coal facies. Vegetation has been reconstructed with the help of paleobotany, including palynology, cuticular analysis and wood anatomy (in brown coals) and with the study of petrified peats preserved in coal balls. The microscopical investigation of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative. However, the results of palynological and cuticular analyses should be evaluated with caution considering their varying resistance and, in the case of palynomorphs, their possible extrapaludal origin. Microscopical studies of modern peats derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies, especially in brown coals. The much disputed origin of brown coal lithotypes is considered in detail. For hard coals there seems to be agreement that coal layers rich in vitrite and liptinite-poor clarite were deposited in wet forest swamps, that microlayered liptinite-rich clarites were subaquatic humic muds, and that inertinite-rich durites were oxidized peats. The origin of liptiniterich durites is controversial; they are either subaquatic muds or oxidized peats the latter perhaps from raised bogs. A recent trend is the assumption that may of not all mineable coal seams have been deposited in raised bogs under ombrogeneous, oligotrophic conditions. Although raised bogs with a dense arborescent vegetation are known from Borneo, it seems not probable that most seams (which were deposited in foredeeps or steadily sinking graben zones) are of ombrogeneous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for some seams. But, as in modern peats, striking changes of seam facies are commonly caused by hydrological events, for example, inundations as a consequence of crevasses or of fires that burnt the peat. The origin of the inertinite-rich Gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub-arctic peats is recommended. Coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite, as well as hydrogen-rich vitrinites with a relatively low reflectance and high fluorescence, all due to a strong bacterial activity in peats of low acidity.Proposals for further work will be made in the conclusions [see Discussion].

Anoxic basins of the eastern Mediterranean: An overview

It is well known that the Mediterranean Sea underwent several episodes of basin‐wide stagnation in the Plio/Pleistocene, but extant anoxic basins were first discovered between 1983 and 1984 in the Strabo Trench and in the southwestern slopes of the Mediterranean Ridge, facing the Sirte Abyssal Plain. Since then, several expeditions were carried out to investigate the geology and physiography of the basins as well as the physical and chemical characters of the water column. Although the geodynamic settings of the Tyro and Bannock basins are quite different, they are very deep, closed and filled by dense, salty, cold brines, whose presence is attributed to submarine dissolution of Messinian evaporites. Bannock Basin is interpreted as a collapse basin, with a complex configuration, central domes and several satellite basins most of which are anoxic. Unlike the Tyro Basin, it is characterized by precipitation of gypsum, occurring as euhedral crystals within the sediments, and dredged along the steep wall bordering the main basin to the East. The interface separating normal seawater from the brines corresponds to a well‐defined pycnocline with a density contrast of approximately 20%, where strong bacterial activity seems to occur and a sudden decrease in transmittance is recorded. Studies on the water column document drastic changes of all the various parameters measured (O2, H2S, Ca, PO4, Ba) across the interface. Sediments deposited beneath the brines are anoxic. This kind of geologically induced anoxia is persistent and diachronous, in contrast with the isochronous, episodic, repetitive and climatically induced anoxia recorded in the same area of the eastern Mediterranean.

The genesis of coal from the viewpoint of coal geology

The genesis of the microscopic constituents of coal (macerals) and of maceral associations (microlithotypes) representing various coal components is discussed in light of recent advances that have been made in the study of coals and modern peats. Peat microscopy especially promoted the understanding of humification and biological gelification, both of which are decisive for the genesis of huminities/vitrinites in brown coals and hard coals, respectively. Microbial activity during peatification has been testified by chemists, microbiologists, and petrologists, and also recently by electron-microscopical observations matter and later, influences the chemical, physical and technological properties of vitrinites. Geochemical gelification transform the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal. In this process, the hydrogel brown coal is transformed to the bitumogel bituminous coal. “Coal as a source rock for oil” has become an important research subject for coal petrologists (and oil exploration!). The formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to “coalification jumps” of the macerals, especially liptinite and vitrinites and to the generation of secondary macerals like exsudatinite (bitumen) and micrinite (dead carbon). Bituminization in coal has been revealed by the use of fluorescence microscopy that also showed the presence of new liptinite macerals (bituminite, fluorinite and exsudatinite) and suggests a higher proportion of algal material in coals than was thought earlier. The genesis of various inertinites will probably become an increasingly important subject of research, especially with regard to “rankinertinites” which seem to attain their high inertinitic reflectance during early coalification. Besides the origin of macerals, the origin of various coal facies in terms of maceral associations is considered in relation to the paleogeographic depositional milieu, the peat-forming vegetation, paleoclimate, water and nutrient supply, acidity, marine and calcareous influence, and fire, with examples from Euramerican Carboniferous coals, Gondwana coals and Tertiary brown coals. Vegetation and water and oxygen supply (Eh-conditions) are most important for the formation of coal facies. Vegetation has been reconstructed with the help of paleobotany, including palynology, cuticular analysis and wood anatomy (in brown coals) and with the study of petrified peats preserved in coal balls. The microscopical investigation of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative. However, the results of palynological and cuticular analyses should be evaluated with caution considering their varying resistance and, in the case of palynomorphs, their possible extrapaludal origin. Microscopical studies of modern peats derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies, especially in brown coals. The much disputed origin of brown coal lithotypes is considered in detail. For hard coals there seems to be agreement that coal layers rich in vitrite and liptinite-poor clarite were deposited in wet forest swamps, that microlayered liptinite-rich clarites were subaquatic humic muds, and that inertinite-rich durites were oxidized peats. The origin of liptiniterich durites is controversial; they are either subaquatic muds or oxidized peats the latter perhaps from raised bogs. A recent trend is the assumption that may of not all mineable coal seams have been deposited in raised bogs under ombrogeneous, oligotrophic conditions. Although raised bogs with a dense arborescent vegetation are known from Borneo, it seems not probable that most seams (which were deposited in foredeeps or steadily sinking graben zones) are of ombrogeneous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for some seams. But, as in modern peats, striking changes of seam facies are commonly caused by hydrological events, for example, inundations as a consequence of crevasses or of fires that burnt the peat. The origin of the inertinite-rich Gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub-arctic peats is recommended. Coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite, as well as hydrogen-rich vitrinites with a relatively low reflectance and high fluorescence, all due to a strong bacterial activity in peats of low acidity. Proposals for further work will be made in the conclusions [see Discussion].

The genesis of coal from the viewpoint of coal petrology

The genesis of the microscopic constituents of coal (macerals) and of maceral associations (microlithotypes) representing various coal facies is discussed in the light of recent advances that have been made in the study of coals and modern peats. Peat microscopy especially promoted the understanding of humification and biological gelification, both of which are decisive for the genesis of huminites/vitrinites in brown coals and hard coals, respectively. Microbial activity during peatification has been documented by chemists, microbiologists and petrologists and, recently, by electron-microscopical observations in coals. This activity leads to the incorporation of lipid substances into the humic matter and, later, influences the chemical, physical and technological properties of vitrinites. Geochemical gelification transforms the huminites of brown coals into the vitrinites of bituminous coals and is probably caused by the onset of bitumen generation in coal. In this process, the hydrogel brown coal is transformed to the bitumogel bituminous coal. Coal as a source rock for oil has become an important research subject for coal petrologists and oil exploration. The formation of more or less liquid bitumen and its later cracking to gaseous hydrocarbons leads to the “coalification jumps” of the macerals, especially liptinites and vitrinites and to the generation of secondary macerals like exsudatinite (bitumen) and micrinite (dead carbon). Bituminization in coal has been revealed by the use of fluorescence microscopy which also found the presence of new liptinite macerals (bituminite, fluorinite and exsudatinite) and suggests a higher proportion of algal material in coals than was thought earlier. The genesis of various types of inertinite macerals will probably become an increasingly important subject of research, especially with regard to “rank-inertinites” that seem to attain their high inertinitic reflectance initially during coalification. Besides the origin of macerals, the origin of various coal facies in terms of maceral associations is considered in relation to the palaeogeographic depositional milieu, the peat-forming vegetation, palaeoclimate, water and nutrient supply, acidity, marine and calcareous influence and fire, with examples from Euramerican Carboniferous coals, Gondwana coals, and Tertiary brown coals. Vegetation, water and oxygen supply (Eh-conditions) are most important for the generation of coal facies. Vegetation has been reconstructed with the help of palaeobotany, including palynology, cuticular analysis and wood anatomy (in brown coals) and with the study of petrified (permineralized) peats preserved in coal balls. The microscopical investigations of botanically recognizable plant remains isolated from coals or accompanying rocks has been especially informative. However, the results of palynological and cuticular analyses should be evaluated with caution, considering the varying resistance of palynomorphs and cuticles and, in the case of palynomorphs, their possible extrapaludal origin. Microscopical studies of modern peats that were derived from different types of vegetation growing in different hydrological environments have been very helpful in interpreting coal facies, especially in brown coals. The much disputed origin of brown-coal lithotypes is considered in detail. For hard coals there seems to be agreement that coal layers rich in vitrites and liptinite-poor clarite were deposited in wet-forest swamps, that microlayered liptinite-rich clarites are sub-aquatic humic muds, and that inertinite-rich durites represent oxidized peats. The origin of liptinite-rich durites is controversial (either subaquatic muds or oxidized peats, the latter perhaps from raised bogs). A recent trend in the literature is the assumption that many if not all mineable coal seams have been deposited in raised bogs under ombrogenous, oligotrophic conditions. Although raised bogs with a dense arborescent vegetation are known from Borneo, it seems not probable that most seams (which were deposited in foredeeps or steadily sinking graben zones) are of ombrogenous origin although a succession from relatively wet and eutrophic to relatively dry and oligotrophic conditions may be true for occasional seams. But, as in modern peats, striking changes of coal facies are commonly caused by hydrological events, e.g., inundations as a consequences of crevasses or of fires that burned the peat. The origin of the inertinite-rich Gondwana coals is discussed in relation to their specific climatic conditions and a comparison with sub-arctic peats is recommended. Coals influenced by marine and calcareous conditions are characterized by high contents of sulfur and pyrite, as well as by hydrogen-rich vitrinites with a relatively low reflectance and high fluorescence, all due to a strong bacterial activity in peats of low acidity. Proposals for further research are made in the conclusions.

MICROBIOLOGICAL ASPECTS OF SPONTANEOUS WORT FERMENTATION IN THE PRODUCTION OF LAMBIC AND GUEUZE

Lambic and Gueuze are special Belgian beers obtained by spontaneous fermentation. Micro-organisms involved in this fermentation were counted and differentiated using several selective growth media. Micro-organisms were also isolated from samples of Lambic of different age and originating from different casks and brews and identified by classical tests. The following general pattern of microbial development was observed. After 3 to 7 days the fermentation started with the development of wort Enterobacteriaceae and strains of Kloeckera apiculata. These organisms were overgrown after 3 to 4 weeks by strains of Saccharomyces cerevisiae and S. bayanus. These were responsible for the main fermentation, lasting for 3 to 4 months. This was followed by a strong bacterial activity. This period was dominated by the growth of strains of Pediococcus cerevisiae. These reached their maximal numbers during the summer months and were responsible for a fivefold increase in lactic acid concentration. In some casks they caused ropiness. After the main fermentation period Lambic is very sensitive to spoilage by acetic acid bacteria of the genus Acetomonas. The presence of air may be the determining factor for their development. After 8 months a new increase in yeast cells was noted. These belonged now mainly to the genus Brettano-myces bruxellensis and Br. lambicus. They caused a further slow decrease in residual extract and the appearance of special flavours. Oxidative yeasts of the genera Candida, Cryptococcus, Torulopsis and Pichia were also detected and may be responsible for the formation of a flim on the beer surface after the main fermentation.