• Journal of the Korean Wood Science and Technology
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• v.25 no.3
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• pp.83-95
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• 1997

The degradation mode of lignocellulose by anaerobic ruminal cellulolytic bacterium Ruminococcus albus F-40 was investigated. Birchwood holocellulose and filter paper were incubated as the sole carbohydrate sources with using the Hungate techniques. After 2 or 4 days of incubation, samples were employed for chemical and electron microscopic evaluations. The degradation rate of cellulosic substrates and the adhesion rate of bacteria to the substrates increased proportionally with the decrease of relative crystallinity of cellulose, indicating the preferential breakdown of amorphous cellulose, by this bacterium. X-ray diffraction analyses and polarized light microscopy showed, however, that crystalline cellulose was also degraded by R. albus. FT-IR spectra indicated that not only cellulose but hemicellulose was also degraded by this bacterium. Electron microscopic investigations showed the protuberant structures on the surface of R. albus. These structures were much more significant when bacterial cells were grown in the media containing insoluble substrates, such as cellulose, indicating clearly that bacterial protuberant structures were induced by the substrates. Protuberant structures extended from the bacterial cells adhered tightly to the substrates and numerous vesicles covered the surface of cellulosic substrates affected. Cellulosome-like structures were distributed on the cellulose matrix. Electron microscopic works showed that diverse surface organells of R. albus were involved in the degradation of cellulosic materials. SEM examinations showed the breakdown of cellulose by R. albus was proceeded by severeal routes : short fiber formation, defibrillation and destrafication of cellulose microfibril.

• Asian-Australasian Journal of Animal Sciences
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• v.9 no.3
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• pp.303-307
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• 1996

The degree of autolysis and presence of cell-wall degrading enzymes in an anaerobic ruminal fungus, Piromyces communis OTSI, grown in liquid medium, was monitored to evaluate the effect of self-digestion on fungal biomass. After a 30 days incubation period fungal dry weight decreased by 45% and the cell wall component chitin decreased by 22%. Chitinase activity detected in the supernatant was mainly of the endotype and peaked at day 6 of the incubation. ${\beta}-1$, 3-glucanase was detected from day 4 and increased throughout the incubation period. Autolysis was a slow process, and under natural conditions it is unlikely that it plays a significant role in the degradation of the spent fungal vegetative stage in the rumen.

• Environmental Engineering Research
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• v.19 no.4
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• pp.355-361
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• 2014

The wastewater treatment with a two-phase expanded granular sludge bed (EGSB) system for anaerobic degradation of acetate, benzoate, terephtalate and p-toluate from purified terephtalic acid (PTA) production was studied. The feasibility and effectiveness of the system was evaluated in terms of organic oxidation by chemical oxygen demand (COD), gas production, bacterial adaptability and stability in the granular sludge. Average removal efficiencies 93.5% and 72.7% were achieved in the EGSB reactors under volumetric loading rates of $1.0-15kg-COD/m^3/day$ and terephtalate and p-toluate of 351-526 mg/L, respectively. Gas production reached total methane production rate of 0.30 L/g-COD under these conditions in the sequential EGSB reactor system. Higher strength influent COD concentration above 4.8 g-COD/L related to field conditions was fed to observe the disturbance of the EGSB reactors.

• Asian-Australasian Journal of Animal Sciences
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• v.10 no.6
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• pp.541-550
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• 1997

Anaerobic chytridiomycete fungi are now well recognized as one of the major components of rumen microflora. Since the discovery of anaerobic fungi, the knowledge upon their morphology and physiology has been accumulated. It is certain that they gave roles in ruminal fiber digestion, although their quantitative contribution to rumen digestion is still unclear. Their role in fiber digestion is complicated by the dietary factors and the interaction with other microorganisms. We aim at reviewing such information in this article. Considerable attention gas been paid to the polysaccharidase of these fungi. Analysis on the fungal genes encoding these enzymes has been performed in several laboratories. This article also covers the genetical analysis of fungal polysaccharidases.

• Journal of Microbiology and Biotechnology
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• v.21 no.3
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• pp.252-255
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• 2011

Both Escherichia coli (E. coli) and Salmonella enterica serovar Typhimurium (S. Typhimurium) have a tdc operon that encodes enzymes involved in a metabolic pathway for the degradation of L-serine and L-threonine. However, S. Typhimurium does not have the tdcR gene, which is a positive regulator in E. coli. In the present study, transcriptional analysis revealed that tdcA expression in E. coli is higher under anaerobic than aerobic growth conditions, but the opposite is true in S. Typhimurium. Interestingly, a tdcR mutant strain of E. coli showed a similar expression pattern to that observed in S. Typhimurium and was also induced by anaerobic shock. These results suggest that the induction of tdcA expression by anaerobic conditions is observable when tdcA expression is low owing to the absence of TdcR.

• Asian-Australasian Journal of Animal Sciences
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• v.27 no.4
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• pp.600-607
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• 2014

The aim of this study was to assess the effect of substrate to inoculum ratio (S/I ratio) on the biochemical methane potential (BMP) and anaerobic biodegradability ($D_{deg}$) of different piggery slaughterhouse wastes, such as piggery blood, intestine residue, and digestive tract content. These wastes were sampled from a piggery slaughterhouse located in Kimje, South Korea. Cumulative methane production curves for the wastes were obtained from the anaerobic batch fermentation having different S/I ratios of 0.1, 0.5, 1.0, and 1.5. BMP and anaerobic biodegradabilities ($D_{deg}$) of the wastes were calculated from cumulative methane production data for the tested conditions. At the lowest S/I ration of 0.1, BMPs of piggery blood, intestine residue, and digestive tract content were determined to be 0.799, 0.848, and $1.076Nm^3kg^{-1}-VS_{added}$, respectively, which were above the theoretical methane potentials of 0.539, 0.644, and $0.517Nm^3kg^{-1}-VS_{added}$ for blood, intestine residue, and digestive tract content, respectively. However, BMPs obtained from the higher S/I ratios of 0.5, 1.0, and 1.5 were within the theoretical range for all three types of waste and were not significantly different for the different S/I ratios tested. Anaerobic biodegradabilities calculated from BMP data showed a similar tendency. These results imply that, for BMP assay in an anaerobic reactor, the S/I ratio of anaerobic reactor should be above 0.1 and the inoculum should be sufficiently stabilized to avoid further degradation during the assay.

• Journal of Microbiology and Biotechnology
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• v.26 no.10
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• pp.1765-1773
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• 2016

Wastewater containing kraft lignin (KL) discharged from pulp and paper industries could cause serious environmental contamination. Appropriate effluent treatment is required to reduce the pollution. Investigations on anaerobic bacteria capable of degrading KL are beneficial to both lignin removal and biofuel regeneration from the effluent. In this paper, an anaerobic strain capable of degrading KL was isolated from the sludge of a pulp and paper mill and identified as Dysgonomonas sp. WJDL-Y1 by 16S rRNA analysis. Optimum conditions for KL degradation by strain WJDL-Y1 were obtained at initial pH of 6.8, C:N ratio of 6 and temperature of 33℃, based on statistical analyses by response surface methodology. For a 1.2 g/l KL solution, a COD removal rate of 20.7% concomitant with biomass increase of 17.6% was achieved after 4 days of incubation under the optimum conditions. After the treatment by strain WJDL-Y1, KL was modified and degraded.

• Transactions of the Korean hydrogen and new energy society
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• v.30 no.3
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• pp.269-275
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• 2019

This study was conducted to evaluate the microbial communities in coupled system of a microbial electrolysis cell and an anaerobic digestion. Glucose, butyric acid, propionic acid and acetic acid were used as substrates. The maximum methane production and methane production rate of propionic acid respectively were $327.9{\pm}6.7mL\;CH_4/g\;COD$ and $28.3{\pm}3.1mL\;CH_4/g\;COD{\cdot}d$, which were higher than others. Microbial communities' analyses indicated that acetoclastic methangens were predominant in all systems. But the proportion of hydrogenotrophic methanogens was higher in the system using propionic acid as a substrate when compared to others. In coupled system of a microbial electrolysis cell and anaerobic digestion, the methane production was higher as the distribution of hydrogen, which was generated by substrate degradation, and proportion of hydrogenotrophic methanogens was higher.

• Korean Journal of Environmental Agriculture
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• v.19 no.4
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• pp.300-308
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• 2000

The degradation of herbicide $^{14}C-bifenox$ was studied in soils under anaerobic conditions. $^{14}C-bifenox$ was treated in silty loam and sandy loam soils, respectively at a rate of 2.1 mg/kg, and the soil was incubated under anaerobic conditions at $25^{\circ}C$ for 180 days. The mineralization, solvent extractable and non-extractable residues, degradation products of bifenox were investigated during the experiments. The relative amounts of $^{14}CO_2$ were 1.97 and 0.9% of applied $^{14}C$ in silty loam and sandy loam soils, respectively. The non-extractable residues of sandy loam soil increased dramatically up to 79.12% of applied $^{14}C$, and were higher than those of silt loam soil, suggesting physico-chemical properties and especially organic matter contributed to the difference of $^{14}C$ between two soils. The non-extractable residues were formed mainly humin fraction and increased with time. The major metabolites were nitrofen, 5-(2,4-dichlorophenoxy)-2-Nitrobenzoate, 2,4-dichlorophenoxy aniline and methyl 5-(2,4-dichlorophenoxy) anthranilate by GC/MS analysis. From the results of volatilization, mineralization and degradation of bifenox, bifenox was stable chemically and biologically in soil.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.93.2-93
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• 1996

No Abstract, See Full Text