Distribution of Bdellovibrio bacteriovorus in sewage works, river water, and sediments.

Bdellovibrio was found in all liquid phases of the sewage works examined. The predator was also found in all the river sediments and sewage-polluted river waters examined but could not be found in some unpolluted river waters. Bdellovibrio was able to multiply on the high numbers of bacteria present in the aerobic percolating filter film but could not survive in anaerobic sludge. Similarly, the predator was present in the aerobic surface layers of river sediments but not in the anaerobic bottom layers. The major source of Bdellovibrio in the polluted rivers examined were sewage works effluents, and numbers in both river water and sediment were correlated with river water quality. It was unlikely that Bdellovibrio was important in reducing numbers of other bacteria in either sewage or river sediment.     

Distribution of Bdellovibrio bacteriovorus in sewage works, river water, and sediments.

Bdellovibrio was found in all liquid phases of the sewage works examined. The predator was also found in all the river sediments and sewage-polluted river waters examined but could not be found in some unpolluted river waters. Bdellovibrio was able to multiply on the high numbers of bacteria present in the aerobic percolating filter film but could not survive in anaerobic sludge. Similarly, the predator was present in the aerobic surface layers of river sediments but not in the anaerobic bottom layers. The major source of Bdellovibrio in the polluted rivers examined were sewage works effluents, and numbers in both river water and sediment were correlated with river water quality. It was unlikely that Bdellovibrio was important in reducing numbers of other bacteria in either sewage or river sediment.     

Modeling the system dynamics for nutrient removal in an innovative septic tank media filter

A next generation septic tank media filter to replace or enhance the current on-site wastewater treatment drainfields was proposed in this study. Unit operation with known treatment efficiencies, flow pattern identification, and system dynamics modeling was cohesively concatenated in order to prove the concept of a newly developed media filter. A multicompartmental model addressing system dynamics and feedbacks based on our assumed microbiological processes accounting for aerobic, anoxic, and anaerobic conditions in the media filter was constructed and calibrated with the aid of in situ measurements and the understanding of the flow patterns. Such a calibrated system dynamics model was then applied for a sensitivity analysis under changing inflow conditions based on the rates of nitrification and denitrification characterized through the field-scale testing. This advancement may contribute to design such a drainfield media filter in household septic tank systems in the future.     

Production of polyhydroxybutyrate by activated sludge performing enhanced biological phosphorus removal

In this study, polyhydroxybutyrate (PHB) – a biodegradable plastics material – was produced by activated sludge performing enhanced biological phosphorus removal (EBPR) in batch experiments under anaerobic, aerobic and anaerobic/aerobic conditions. Under anaerobic conditions, the maximum PHB content of the dry biomass was 28.8% by weight, while under aerobic or anaerobic/aerobic conditions, the maximum PHB content was about 50%. The PHB production rate with respect to the volatile suspended solids (VSS) was: (i) 70 mg/(g VSS) h under aerobic conditions that followed anaerobic conditions, (ii) 156 mg/(g VSS) h under anaerobic condition, and (iii) 200 mg/(g VSS) h under aerobic conditions with energy also supplied from polyphosphate. A side stream, with initially anaerobic conditions for PHB accumulation and phosphorus release, and then aerobic conditions for PHB accumulation, was proposed. In this side stream, biomass with a high PHB content and a high PHB production rate could be both achieved.     

Relationship between the production of spirosomes and anaerobic glycolysis activity in Escherichia coli B

The effects of culture conditions (aerobic or anaerobic) and glucose in the medium on the production of spirosomes in Escherichia coli B were studied by SDS-PAGE and electron microscopy. The Mr of the spirosome of E. coli B was estimated to be 97,000. Electron microscopy revealed that the amount of spirosomes derived from anaerobic cultures was about eightfold larger than that from aerobic cultures. In SDS-PAGE, the bands of spirosome protein derived from anaerobic cultures were more intense than those derived from aerobic cultures, either in peptone water or in Davis-Mingioli's minimal medium. With increased glucose concentration under aerobic conditions, the intensity of the band of spirosome protein was similar to that observed under anaerobic conditions in basal media. These results suggest that spirosome production by E. coli B is related to its anaerobic glycolysis activity.     

Enhanced biodegradation of methoxychlor in soil under sequential environmental conditions.

Ring-U-[14C]methoxychlor [1,1-bis(p-methoxyphenyl)-2,2,2-trichloroethane] was incubated in soil under aerobic and anaerobic conditions. Primary degradation of methoxychlor occurred under anaerobic conditions, but not under aerobic conditions, after 3 months of incubation. Analysis of soil extracts, using gas chromatography, demonstrated that only 10% of the compound remained at initial concentrations of 10 and 100 ppm (wt/wt) of methoxychlor. Evidence is presented that a dechlorination reaction was responsible for primary degradation of methoxychlor. Analysis of soils treated with 100 ppm of methoxychlor in the presence of 2% HgCl2 showed that 100% of the compound remained after 3 months, indicating that degradation in the unpoisoned flasks was biologically mediated. Methanogenic organisms, however, are probably not involved, as strong inhibition of methane production was observed in all soils treated with methoxychlor. During the 3-month incubation period, little or no evaluation of 14CO2 or 14CH4 occurred under either aerobic or anaerobic conditions. Cometabolic processes may be responsible for the extensive molecular changes which occurred with methoxychlor because the rate of its disappearance from soil was observed to level off after exhaustion of soil organic matter. After this incubation period, soils previously incubated under anaerobic conditions were converted to aerobic conditions. The rates of 14CO2 evolution from soils exposed to anaerobic and aerobic sequences of environments ranged from 10- to 70-fold greater than that observed for soils exposed solely to an aerobic environment.     

Anaerobic incubation of membrane filter cultures for improved detection of fecal coliforms from recreational waters.

Anaerobic incubation of membrane filter cultures significantly enhanced detection of fecal coliforms in surface-water samples from recreational beaches. In contrast to standard aerobic incubation, anaerobic incubation suppressed overgrowth of masking, noncoliform bacteria but did not increase the frequency of fecal coliform recovery.     

DNA-methyltransferase activities in Streptomyces antibioticus

Abstract To quantitate ammonia production by the intestinal flora, ammonia levels in arterial blood and the venous effluent of the small and large bowel of conventional, selectively decontaminated, germ-free and gnotobiotic rats were measured.
When the anaerobic flora was removed by decontamination a significant decrease in ammonia levels was observed in the effluent of both the small and large intestine. Decontamination of aerobic flora did not result in depression of ammonia production. Gnotobiotic rats colonised with an anaerobic flora or with a mixed aerobic and anaerobic flora, showed a slight increase in ammonia levels. No increase in ammonia production was observed when rats were colonised with aerobic flora. These results indicate that the Enterobacteriaceae were not responsible for ammonia generation.
The increase in ammonia levels after colonisation with anaerobic or mixed anaerobic/aerobic flora did not completely restore ammonia levels, despite reaching bacterial counts which were comparable to those in conventional rats. This may be explained by the limited number of species with which the rats were colonized. The finding that aerobic flora does not significantly contribute to ammonia production suggests that neomycin, known to be exclusively effective against aerobic flora, must have other effects to explain improvement of hepatic encephalopathy.     

Biodegradation of central intermediate compounds produced from biodegradation of aromatic compounds

In this study I consider the incomplete biodegradation of aromatic compounds during the wastewater cycle between aerobic or anaerobic zones in biological nutrient removal processes, including aerobic biodegradation of compounds (such as cyclohex-1-ene-1-carboxyl-CoA) produced during the incomplete anaerobic biodegradation of aromatic compounds, and anaerobic biodegradation of compounds (such as catechol, protocatechuate, and gentisic acid) produced during the incomplete aerobic biodegradation of aromatic compounds. Anaerobic degradation of the aerobic central intermediates that result from the incomplete aerobic degradation of aromatic compounds usually leads to benzoyl-CoA. On the other hand, aerobic degradation of the anaerobic central intermediates that result from the incomplete anaerobic degradation of aromatic compounds usually leads to protocatechuate.     

Integrated biological process for olive mill wastewater treatment

The biological process for OMW treatment is based on an aerobic detoxification step followed by methanization step and aerobic post-treatment.The first aerobic detoxification step of OMW supplemented with sulfate and ammonium was carried out by the growth of Aspergillus niger in a bubble column. This step decreased OMW toxicity and increased its biodegradability because of phenolic compounds degradation. Growth of A. niger resulted in 58% COD removal, with production of biomass containing 30% proteins (w/w). Filtration of OMW was enhanced by this fermentation because the suspended solids were trapped in the mycelium. The filtrate liquid was then methanized using an anaerobic filter packed with flocoor. This reactor showed a short start up and a good stability. COD removal was around 60% and the methane yield (1 CH₄/g COD removed) was close to the theoretical yield.The anaerobic filter effluent was treated in an activated sludge fluidized reactor containing olive husk as a packing material. Husks were maintained in fluidization state by the aeration. This step induces COD removal at 45% and sludge (up to 2 g/dm³).The entire process allowed a global COD reduction up to 90%; however, the black colour due to polyphenolic compounds with high molecular weight persisted.     

Anaerobic and aerobic metabolism of diverse aromatic compounds by the photosynthetic bacterium Rhodopseudomonas palustris.

The purple nonsulfur photosynthetic bacterium Rhodopseudomonas palustris used diverse aromatic compounds for growth under anaerobic and aerobic conditions. Many phenolic, dihydroxylated, and methoxylated aromatic acids, as well as aromatic aldehydes and hydroaromatic acids, supported growth of strain CGA001 in both the presence and absence of oxygen. Some compounds were metabolized under only aerobic or under only anaerobic conditions. Two other strains, CGC023 and CGD052, had similar anaerobic substrate utilization patterns, but CGD052 was able to use a slightly larger number of compounds for growth. These results show that R. palustris is far more versatile in terms of aromatic degradation than had been previously demonstrated. A mutant (CGA033) blocked in aerobic aromatic metabolism remained wild type with respect to anaerobic degradative abilities, indicating that separate metabolic pathways mediate aerobic and anaerobic breakdown of diverse aromatics. Another mutant (CGA047) was unable to grow anaerobically on either benzoate or 4-hydroxybenzoate, and these compounds accumulated in growth media when cells were grown on more complex aromatic compounds. This indicates that R. palustris has two major anaerobic routes for aromatic ring fission, one that passes through benzoate and one that passes through 4-hydroxybenzoate.     

Energy-dependent inactivation of citrate lyase in Enterobacter aerogenes.

Enterobacter aerogenes was grown in continous culture with ammonia as the growth-limiting substrate, and changes in citrate lyase and citrate synthase activities were monitored after growth shifts from anaerobic growth on citrate to aerobic growth on citrate, aerobic growth on glucose, anaerobic growth on glucose, and anaerobic growth on glucose plus nitrate. Citrate lyase was inactivated during aerobic growth on glucose and during anaerobic growth with glucose plus nitrate. Inactivation did not occur during anaerobic growth on glucose, and as a result of the simultaneous presence of citrate lyase and citrate synthase, growth difficulties were observed. Citrate lyase inactivation consisted of deacetylation of the enzyme. The corresponding deacetylase could not be demonstrated in cell extracts, and it is concluded that, as in a number of other inactivations, electron transport to oxygen or nitrate was required for inactivation.     

Survival rates of parasite eggs in sludge during aerobic and anaerobic digestion.

The effects of mesothermic anaerobic or aerobic sludge digestion on survival of eggs from the roundworms Ascaris suum, toxocara canis, Trichuris vulpis, and Trichuris suis and from the rat tapeworm Hymenolepis diminuta were studied. Destruction of eggs throughout a 15-day treatment period, as well as their viabilities after reisolation, was analyzed. The laboratory model digesters used in this study were maintained at a 15-day retention schedule, partially simulating a continuously operating system. Ascaris eggs were destroyed in the anaerobic (23%) or aerobic (38%) digesters, and 11% Trichuris eggs were destroyed in the aerobic digesters. Trichuris eggs in anaerobic digesters and Toxocara eggs in either anaerobic or aerobic digesters were not destroyed. Destruction of eggs in digesters was correlated with the state of the eggs before subjection to the treatment processes; i.e., some Ascaris and Trichuris eggs were already embryonated in host intestinal contents or feces and hence past their most resistant stage. The viabilities of Ascaris and Toxocara eggs that survived the digestion processes were greater in anaerobically treated than in aerobically treated material. Eggs from Hymenolepis were nonviable before use in the experiments. However, they were more effectively destroyed in aerobic digesters than in anaerobic digesters.     

Attack on Lignified Grass Cell Walls by a Facultatively Anaerobic Bacterium

A filamentous, facultatively anaerobic microorganism that attacked lignified tissue in forage grasses was isolated from rumen fluid with a Bermuda grass-containing anaerobic medium in roll tubes. The microbe, designated 7-1, demonstrated various colony and cellular morphologies under different growth conditions. Scanning electron microscopy revealed that 7-1 attacked lignified cell walls in aerobic and anaerobic culture. 7-1 predominately degraded tissues reacting positively for lignin with the chlorine-sulfite stain (i.e., sclerenchyma in leaf blades and parenchyma in stems) rather than the more resistant acid phloroglucinol-positive tissues (i.e., lignified vascular tissue and sclerenchyma ring in stems), although the latter tissues were occasionally attacked. Turbidimetric tests showed that 7-1 in anaerobic culture grew optimally at 39°C at a pH of 7.4 to 8.0. Tests for growth on plant cell wall carbohydrates showed that 7-1 grew on xylan and pectin slowly in aerobic cultures but not with pectin and only slightly with xylan in anaerobic culture. 7-1 was noncellulolytic as shown by filter paper tests. The microbe used the phenolic acids sinapic, ferulic, and p-coumaric acids as substrates for growth; the more highly methoxylated acids were used more effectively.     

Aerobic and anaerobic biodegradability of 1-Anthraquinone sulphonate

 The present work investigates 1-anthraquinone sulphonate (1-AS) biodegradation under (i) aerobic conditions using domestic activated sludge as inoculum, (ii) anaerobic conditions using sludge from an anaerobic domestic wastewater treatment digestor in a sulphate-containing or methanogenic environment, (iii) a combination of anaerobic followed by aerobic conditions. The process was evaluated in terms of primary degradation, i.e. 1-AS elimination and ultimate degradation, as total dissolved organic carbon removal. It was shown that aerobic conditions lead to the complete primary and ultimate degradation, of 1-AS. By contrast, neither under sulphato-reductive nor methanogenic conditions does anaerobic digestion lead to the significant degradation of 1-AS. The use of anaerobic treatment followed by aerobic treatment did not improve degradation. Indeed aerobic post-treatment resulted in the re-appearance of pollutant in the medium even though this had been partly degraded under anaerobic conditions. Received: 12 October 1995/Received revision: 18 December 1995/Accepted: 8 January 1996     

Comparative Assessment of the Aerobic and Anaerobic Microfloras of Earthworm Guts and Forest Soils

Aerobic and anaerobic microbial potentials of guts from earthworms (Lumbricus rubellus Hoffmeister and Octolasium lacteum (Oerl.)) collected from a beech forest were evaluated. On the basis of enumeration studies, microbes capable of growth under both aerobic and anaerobic conditions were more numerous in the earthworm intestine than in the beech forest soil from which the worms were obtained. The intestine of worms displayed nearly equivalent aerobic and anaerobic microbial growth potentials; in comparison, soils displayed greater aerobic than anaerobic microbial growth potentials. Hence, the ratio of microbes capable of growth under obligately anaerobic conditions to those capable of growth under aerobic conditions was higher with the worm intestine than with the soil. Process level studies corroborated these population differentials: (i) under anaerobic conditions, worm gut homogenates consumed glucose, cellobiose, or ferulate more readily than did soil homogenates; and (ii) under aerobic conditions, worm gut homogenates consumed cellobiose or oxygen more readily than did soil homogenates. Collectively, these results reinforce the general concept that the earthworm gut is not microbiologically equivalent to soil and also suggest that the earthworm gut might constitute a microhabitat enriched in microbes capable of anaerobic growth and activity.     

Eradication of Polymyxa betae by Thermal and Anaerobic Conditions and in the Presence of Compost Leachate

The abiotic conditions required for eradication of Polymyxa betae, the vector of Beet necrotic yellow vein virus in sugar beet, were investigated. Survival of resting spores of P. betae was determined under aerobic (30 min, 4 days and 21 days) and anaerobic (4 days) conditions under several temperature regimes in a water suspension and in leachate extracted from an aerobic compost heap. In water under aerobic conditions the lethal temperature was 60, 55 and 40°C for exposure times of 30 min, 4 days and 21 days, respectively. The effect of compost leachate and/or anaerobic conditions on survival of P. betae depended on temperature. After incubation for 4 days at 20°C, no significant effects of anaerobic conditions or leachate on the survival of P. betae were found. However, at 40°C for 4 days under anaerobic conditions, survival of P. betae was significantly lower than survival under aerobic conditions in water as well as in leachate. In leachate taken from an aerobic compost heap, aerobically incubated at 40°C for 4 days, survival of P. betae was significantly lower than survival in water at the same temperature. As anaerobic spots are prevalent in aerobic compost heaps, especially during the thermophilic phase, actual inactivation temperatures under composting conditions are likely to be lower than the temperatures we found for eradication in water under aerobic conditions.     

The effect of environment on lactate dehydrogenase isozymes of cultured somatic cells

The lactate dehydrogenases of HeLa cells grown in an anaerobic environment with either glucose or L-lactate have a higher ratio of A to B sub-units than do the same cells grown in an aerobic environment. This ratio is decreased when the anaerobic environment is made aerobic during cell growth, or when the cells are cultured for the entire growth period in aerobic conditions.     

Relationship between inflammatory cytology of canine seminal fluid and significant aerobic bacterial, anaerobic bacterial or mycoplasma cultures of canine seminal fluid: 95 cases (1987-2000)

Seminal fluid was collected by manual ejaculation from 95 dogs. Quantitative aerobic bacterial, qualitative anaerobic bacterial and mycoplasma cultures were performed on the seminal fluid, and their association with presence of inflammatory cells present in the pellet formed after centrifugation of the fluid was investigated. There was a clinically meaningful aerobic bacterial growth in 28.4%, anaerobic bacterial growth in 13.7%, and mycoplasma growth in 57.9% of the seminal fluid samples. Presence of inflammatory cytology was statistically associated with clinically meaningful aerobic bacterial growth. However, of the 78 dogs (82.1%) with clinically meaningful growth of at least one aerobic, anaerobic or mycoplasma organism, 43 (55.1%) had non-inflammatory seminal fluid cytology.     

Experimental criteria for interpretation of bacterial sensitivity to dioxidine determined by diffusion from the disks

Antibacterial activity of dioxidine against aerobic and facultative anaerobic organisms under conditions of anaerobiosis i. e. conditions really observed for example in abscess cavities or necrotic tissues is 30 to 100 times as high as that under aerobic conditions. There is a relationship between sensitivity of bacteria to dioxidine under aerobic and anaerobic conditions which is expressed by the regression equation. Therefore, comparison of the MICs determined under anaerobic conditions with the growth inhibition zones formed by disks with the drug under aerobic conditions is possible. The MIC of dioxidine was determined under anaerobic conditions for 179 clinical strains of aerobic and facultative anaerobic bacteria and the growth inhibition zones of the same bacteria under aerobic conditions were evaluated with the use of disks containing 100, 75, 50, 25, 20, and 15 micrograms of the drug. The border line. MIC differentiating between resistant and sensitive strains was chosen to be equal to 4 micrograms/ml. Differentiation of the strains into sensitive and resistant ones by the values of the growth inhibition zones was performed with the method of error minimization described by C. Metzler and R. De Haan in 1974. Disks containing 25 micrograms of the drug allowed one to differentiate the strains under aerobic conditions into sensitive and resistant ones: the growth inhibition zones greater than 11 mm corresponded to the sensitive strains (the MIC smaller than 4 micrograms/ml) and the growth inhibition zones smaller than 11 mm corresponded to the resistant strains (the MIC greater than 4 micrograms/ml).