No description available.

No description available.

Anaerobes belonging to the genera Propionibacterium, Bacteroides, Peptococcus, Peptostreptococcus, Eubacterium, Streptococcus and Lactobacillus, which are commonly isolated from the human urogenital flora, were tested for their ability to inhibit the in vitro growth of Neisseria gonorrhoeae strains. / The antigonococcal effect of the anaerobic bacterial strains tested was found not to be due to nutrient depletion and pH change of the media which had supported their growth. This inhibition was not an all-or-none phenomenon since an inhibitory strain did not necessarily interfere with all the gonococcal strains tested. / All the 23 lactobacilli strains tested were found to inhibit the in vitro growth of N. gonorrhoeae. This inhibition was found to be dependent on the composition of the culture medium. In comparison to the gonococcus (GC) and dextrose starch agar (DSA) media, a modified deMan, Rogosa et Sharpe (MRS) medium was more appropriate to support both the growth of lactobacilli and the production of their antigonococcal activity. / For the other 32 anaerobic bacterial strains tested, six were selected for their large antigonococcal spectrum of activity. These strains were Peptostreptococcus anaerobius (Pc9,Ps11B,Ps11C), Bacteroides fragilis (B1A), Bacteroides ovatus (B24) and Eubacterium limosum (Ps11A). The antigonococcal activity produced by these six strains appeared to be specific to the gonococcus since a variety of anaerobes and aerobes were not generally inhibited. / E. limosum and B. fragilis strains were further selected to evaluate the production of their antigonococcal activity in liquid medium. E. limosum Ps11A strain produced its inhibitory activity in prereduced brain heart infusion (BHI) broth during the mid-logarithmic phase of growth, when no inhibitory concentration of short-chain fatty acids was detected in the culture medium. Furthermore, when the amounts of short-chain fatty acids produced by E. limosum increased, its antigonococcal activity decreased. Based on these results and on the individual amount of short-chain fatty acids excreted by E. limosum strains, it was concluded that the observed antigonococcal activity was not due to the presence of these acids. However, B. fragilis strains excreted propionic acid in amount reported to be inhibitory to the gonococcus. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI

The use of off-farm materials as amendments in anaerobic digestion of manure is an interesting option due to the benefits of boosting biogas production, and making the process more economical for the farmer. The addition of varying amounts of glycerol, which is a by-product of biodiesel production, was used as an amendment to anaerobic digestion of hog manure in lab-scale tests. The use of 2% glycerol produced the greatest amount of methane and biogas, however stabilization time was high, and the digestion of nutrients in the manure decreased. The addition of 4% glycerol resulted in an overloading of COD and digester failure. The addition of 1% glycerol resulted in a doubling of the methane and biogas production and the acclimation period was quite short, while the effluent quality remained good. There were no detrimental effects of using crude glycerol observed compared to using pure glcyerol. Batch tests also showed that smaller additions of glycerol (0.5%, 1%) produced the highest methane yields and were recommended as good co-substrates for anaerobic digestion with hog manure.

No description available.

Petroleum spills causes contamination of drinking water with carcinogenic aromatic compounds including benzene and cresol. Current knowledge of anaerobic benzene and cresol degradation is extremely limited and it makes bioremediation challenging. Geobacter daltonii strain FRC-32 is a metal-reducing bacterium isolated from radionuclides and hydrocarbon-contaminated subsurface sediments. It is notable for its anaerobic oxidation of benzene and its unique ability to metabolize p-, m-, or o-cresol as a sole carbon source. Location of genes involved in aromatic compound degradation and genes unique to G. daltonii were elucidated by genomic analysis using BLAST. Genes predicted to play a role in aromatic degradation cluster into an aromatic island near the start of the genome. Of particular note, G. daltonii has two copies of the bss genes, which are responsible for the first step in anaerobic toluene oxidation. This bacterium is unique among the family Geobacteraceae and other toluene degraders in this aspect. The a subunits have 74% identity to one another. The remaining genes in each operon are not identical. BssA was upregulated when G. daltonii was grown on benzene and toluene while the grlA was upregulated during growth on m-cresol. Toluene was accumulated during degradation of benzene by cell lysate. Cells grown with benzene and toluene exhibited a similar protein profile compared to cells grown with benzoate. These results indicate that benzene is converted to toluene and further degraded via the toluene pathway. Both the bss and grl operons were predicted to have sigma54-dependent promoters. This was confirmed using 5' RACE and sequence analysis. E. coli transformed with the bss operon were able to grow in the presence of toluene but lost this capability when sigma 54 was knocked out. Growth was restored with complementation of sigma 54. The sigma 54-dependent signaling system bamVW was upregulated in the presence of all aromatic compounds tested. These results suggest that the bss operon is regulated via sigma 54-dependent mechanisms. This study significantly contributes to anaerobic aromatic gene regulation which is crucial in effective oil spill bioremediation.

It was estimated that more than one hundred open reading frames in Pyrococcus furiosus and Thermotoga maritima could encode flavoproteins based on the results of motif search and comparison of genomic annotation to the experimentally characterized flavoproteins. However, only a few flavoproteins have been characterized from those anaerobic hyperthermophiles. It was found T. maritima and Thermotoga hypogea were able to grow in the presence of micromolar level of oxygen. As part of an oxygen removal system, the presence of NADH oxidase was detected in both microorganisms. In T. hypogea, NADH oxidase activity was constant regardless of the presence of oxygen, while in T. maritima it was increased in the presence of oxygen. The purified T. hypogea NADH oxidase was a flavin adenine dinucleotide (FAD)-containing homodimer with subunit molecular mass of 50 kDa. In addition to NADH oxidase activity, it also demonstrated activity of dihydrolipoamide dehydrogenase (DLDH), which is probably involved in glycine decarboxylation. The purified NADH oxidase from T. maritima was a heterodimeric protein of two subunits with molecular weight of 54 and 46 kDa, which were identified to be encoded by TM1432 and TM1433, respectively. Each subunit bore one FAD and the large subunit had one bacterioferritin-associated ferredoxin (BFD)-like [2Fe-2S]-center. Although the T. maritima NADH oxidase had very unusual oxygen sensitivity, the oxygen inactivated enzyme could be fully recovered by incubating with reducing reagents anaerobically. The NADH oxidases from both T. hypogea and T. maritima catalyzed the reduction of oxygen only to hydrogen peroxide. NADH-dependent peroxidase activities were detected in both T. maritima and T. hypogea, suggesting the presence of a multi-component oxygen detoxification system in Thermotoga species. In addition to its NADH oxidase activity, the enzyme from T. maritima exhibited FAD-linked glycerol-3-phosphate dehydrogenase (FAD-GPDH) activity. Along with the glycerol kinase, the FAD-GPDH took part in glycerol utilization in T. maritima. Ferredoxin NAD+ oxidoreductase (FNOR) activity was detected in T. maritima using an NADH:benzyl viologen oxidoreductase (BVOR) assay. The purified enzyme was a homodimeric FAD-containing protein with subunit molecular mass of 37 kDa. The purified enzyme was very active in catalyzing the reduction of BV and methyl viologen (MV) using either NADH or NADPH as electron donor and could indeed catalyze the reduction of NAD+ with the reduced ferredoxin from T. maritima. The purified enzyme was further identified to be encoded by TM0869 and annotated as thioredoxin reductase (TrxR). T. maritima TrxR could not use commercially available thioredoxin (Trx) from Spirulina, but the Trx purified from T. maritima. T. maritima Trx was identified to be encoded by TM0868 and annotated as glutaredoxin (Grx)-like protein, which showed both thioredoxin (Trx) and Grx activity. The purified T. maritima TrxR could catalyze the Trx-dependent reduction of both insulin and DTNB using NAD(P)H as electron donor. The identified Trx-TrxR system in T. maritima is the first one characterized in hyperthermophilic bacteria. T. hypogea has great potential in microbial hydrogen production. The key enzyme involved in this process, hydrogenase, has not been studied yet. The growth-dependent hydrogenase activity was detected in T. hypogea, from which a homotetrameric hydrogenase was purified. The purified T. hypogea hydrogenase did not contain any flavin prosthetic group as speculated, but [Fe-S]-centers. The hydrogenase could catalyze both BV and MV-dependent hydrogen oxidation and MV-dependent hydrogen evolution. Neither NAD(P)H nor NAD(P) could be used as electron carrier for this enzyme. T. hypogea hydrogenase could utilize ferredoxin as electron carrier for both production and oxidation of hydrogen, which suggests that the purified hydrogenase plays an important role in hydrogen metabolism of T. hypogea. It was concluded that flavoproteins can be involved at least in several very important cellular processes such as detoxification of oxygen, utilization of glycerol, redox regulation, and hydrogen metabolism in hyperthermophiles.

Methane can be a potentially inexpensive, widely available electron donor for biological denitrification of wastewater, landfill leachate or drinking water, while no studies have clearly shown nitrate reduction to nitrogen gas. Recently anaerobic methane oxidation (AMO) coupled to partial denitrification (nitrite to nitrogen gas) was found by several studies. A microbial consortium, enriched from anoxic sediments, oxidized methane to carbon dioxide coupled to denitrification in the complete absence of oxygen, though the rates and pathways of AMO coupled to denitrification are still poorly understood. In this study, direct AMO coupled to denitrificaiton of nitrate was proved to be possible and its kinetic parameters were experimentally determined. Using a set of batch experiments designed to provide the best estimates of each parameter, these parameters were obtained: maximum specific growth rate (??max) = 0.121/day, maximum substrate consumption rate (qmax) = 1.63 mg COD/mg cells-day, true yield (Y) = 0.074 mg cells/mg COD, half maximum-rate substrate concentration (Ks) = 85 ??M CH4, and endogenous decay rate (b) = 0.03/day. This study firstly characterized kinetic parameters of anaerobic methanotrophic denitrifiers, which will substantially help understand anaerobic methane oxidation in natural systems and accelerate methane-utilizing denitrification in engineering systems.

Anaerobic conditions resulting from flooding often lead to enhanced release of phosphorus (P) to overlying water. This study examined the effect of flooding and anaerobic conditions on soil P dynamics. A field ponding study using Scanterbury heavy clay soil (unamended, inorganic fertilizer- or manure-amended), and a laboratory incubation study using 12 soils (unamended or manure-amended) from Manitoba showed that P release to flood water under reduced conditions varied substantially. In the field ponding study, flooding and development of anaerobic conditions did not enhance P release into surface flood or soil pore water. In the incubation study, the response to flooding and anaerobic conditions ranged from a small decrease to a 15-fold increase in dissolved reactive P concentration (DRP) in flood water. Partial least squares analysis indicated that measures of degree of P saturation in soils can effectively predict DRP concentration changes in surface flood water under anaerobic conditions.

The use of off-farm materials as amendments in anaerobic digestion of manure is an interesting option due to the benefits of boosting biogas production, and making the process more economical for the farmer. The addition of varying amounts of glycerol, which is a by-product of biodiesel production, was used as an amendment to anaerobic digestion of hog manure in lab-scale tests. The use of 2% glycerol produced the greatest amount of methane and biogas, however stabilization time was high, and the digestion of nutrients in the manure decreased. The addition of 4% glycerol resulted in an overloading of COD and digester failure. The addition of 1% glycerol resulted in a doubling of the methane and biogas production and the acclimation period was quite short, while the effluent quality remained good. There were no detrimental effects of using crude glycerol observed compared to using pure glcyerol. Batch tests also showed that smaller additions of glycerol (0.5%, 1%) produced the highest methane yields and were recommended as good co-substrates for anaerobic digestion with hog manure.