• Title/Summary/Keyword: Anaerobic fermentation

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Control of Rumen Microbial Fermentation for Mitigating Methane Emissions from the Rumen

  • Mitsumori, Makoto;Sun, Weibin
    • Asian-Australasian Journal of Animal Sciences
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    • v.21 no.1
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    • pp.144-154
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    • 2008
  • The rumen microbial ecosystem produces methane as a result of anaerobic fermentation. Methanogenesis in the rumen is thought to represent a 2-12% loss of energy intake and is estimated to be about 15% of total atmospheric methane emissions. While methanogenesis in the rumen is conducted by methanogens, PCR-based techniques have recently detected many uncultured methanogens which have a broader phylogenetic range than cultured strains isolated from the rumen. Strategies for reduction of methane emissions from the rumen have been proposed. These include 1) control of components in feed, 2) application of feed additives and 3) biological control of rumen fermentation. In any case, although it could be possible that repression of hydrogen-producing reactions leads to abatement of methane production, repression of hydrogen-producing reactions means repression of the activity of rumen fermentation and leads to restrained digestibility of carbohydrates and suppression of microbial growth. Thus, in order to reduce the flow of hydrogen into methane production, hydrogen should be diverted into propionate production via lactate or fumarate.

A Study of Biological Hydrogen Gas Production under Anaerobic Fermentation (혐기성 발효에 의한 생물학적 수소생산에 관한 연구)

  • Yoon, Woo-Hyun;Kim, Hyun-Kab;Lee, Tae-Jin
    • Journal of the Korea Organic Resources Recycling Association
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    • v.14 no.1
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    • pp.131-138
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    • 2006
  • In this study, the optimum condition of pH was investigated on the hydrogen gas production under anaerobic fermentation process. The results of the experiment showed that the optimum condition was observed at pH 6, resulting in 1175.87 mL/L of hydrogen gas production rate and 22.51% theoretical hydrogen conversion ratio. Hydrogen gas production rate and theoretical hydrogen conversion ratio were 901.77 mL/L and 17.48 % respectively at pH 5. At pH 7 and 8, the production rate of hydrogen gas was little low as 82.15 mL/L. Among the organic acids from the sucrose fermentation, propionate was observed as the dominant acid at pH 7 and 8 but butyrate was the dominant at pH 5 and 6.

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Kinetics of Anaerobic Digestion : Temperature Effects on Highly Loaded Digesters (혐기성소화(嫌氣性消化)의 동역학(動力學) : 고부하시(高負荷時)의 온도영향(溫度影響))

  • Chang, Duk;Chung, Tai Hak
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.4
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    • pp.59-67
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    • 1988
  • Anaerobic digestion at the temperature of $35-55^{\circ}C$ was conducted using an artificial sludge of uniform composition. The hydraulic retention time of 5 days was chosen because the temperature effect was effectively shown at a high loading. Inhibition of the methane fermentation decreased as the temperature increased. Acid fermentation was prevalent at the mesophilic and intermediate temperatures, while active methane fermentation took place at $55^{\circ}C$. Temperature not only affects activity of the microorganisms, but also affects physical and chemical properties of the sludge, Digestion inhibition was much reduced when the feed sludge was diluted, and active methane fermentation was possible at all temperatures. The digestion efficiency was governed by the organic loading rate as well as the hydraulic 10ading rate. No reduction of the digestion efficiency at $40-45^{\circ}C$, which had been referred to a critical temperature range, was observed. The digestion efficiency increased monotonically from mesophilic to thermophilic range. Improved settling properties of digested sludge was also recorded at higher temperatures.

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Effects of Substrate to Inoculum Ratio on the Biochemical Methane Potential of Piggery Slaughterhouse Wastes

  • Yoon, Young-Man;Kim, Seung-Hwan;Shin, Kook-Sik;Kim, Chang-Hyun
    • 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.

Antibiotics produced by anaerobic fermentation of Streptococcus sp. An-21-1 isolated from domestic soil I. Screening and identification of anaerobic bacteria (국내토양에서 분리한 혐기성 세균 Streptococcus sp. An-21-1 이 생성하는 항생물질 I. 혐기성 세균의 선별과 동정)

  • Park, Seung-chun;Yun, Hyo-in;Oh, Tae-kwang
    • Korean Journal of Veterinary Research
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    • v.33 no.1
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    • pp.53-60
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    • 1993
  • Anaerobic bacteria are suggested to be potential source for new antibiotics. In order to search for antibiotics from domestic origin, we collected 800 soil samples across Korean locations and could isolate as many as 989 anaerobic strains. Among them 10, strains were found to have good producing capacity of antibiotics. An anaerobe was finally selected due to secreting antibiotics having high antimicrobial activity towards multiple resistant microorganism(E coli JM 83) transformed by genetic engineering technique. Its morphological, physiological and biochemical charateristics were investigated, together with antimicrobial spectrum therefrom. On antimicrobial spectrum study, substance secreted from this strain, had no activities to fungus and yeast. The selected strain showed G(+) and coccal shape, on Gram, staining and electron scanning microscopy, respectively. Biochemically this strain utilized glucose, fructose lactose, sucrose, but did not arabinose, cellulose, rhamnose, sorbitol, trehalose, mannitol. Catalase test showed negative property. Optimal growth temperature was $37^{\circ}C$. The results obtained above suggest this strain Streptococcus faecium subspp. and we named it Streptococcus sp. An-21-1.

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Co-digestion of Thermophilic Acid-fermented Food Wastes and Sewage Sludge (음식물찌꺼기 고온산발효산물과 하수슬러지의 혼합처리)

  • Ahn, Chul-Woo;Jang, Seong-Ho;Park, Jin-Sik
    • Journal of Environmental Science International
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    • v.15 no.9
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    • pp.897-905
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    • 2006
  • This study has been conducted to investigate biodegradation characteristics and optimum mixing ratio for co-digestion with thermophilic acid-fermented food waste and sewage sludge using batch anaerobic digester. As the basis operating conditions for anaerobic digestion, the reaction temperature was controlled $35{\pm}1^{\circ}C$ and stirrer was set 70rpm. Thermophilic acid-fermented food waste and sewage sludge were mixed at the ratio of 10:0, 7:3, 5:5, 3:7, 0:10 and 5;5(food waste : sewage sludge) as the influent substrates. In results of co-digestion according to mixing ratio of thermophilic fermented food wastes and sewage sludge in batch mesophilic anaerobic digestion reactor, $385mL\;CH_4/g\;VS_{added}$ of methane production rate at 1:1 mixing ratio was more than that of any other mixing ratios. Compared with $293mL\;CH_4/g\;VS_{added}$ of methane production rate at 1:1 mixing ratio of food wastes and sewage sludge, pretreatment of food wastes by thermophilic acid fermentation was more effective in co-digestion with sewage sludge.

Characteristic Reactions in Anaerobic Nitrogen Removal from Piggery Waste (돈사폐수의 혐기성 질소제거공정에서 일어나는 특이반응)

  • Hwang, In-Su;Min, Kyung-Sok
    • Journal of Korean Society of Environmental Engineers
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    • v.28 no.3
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    • pp.300-307
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    • 2006
  • Anaerobic ammonium oxidation(ANAMMOX) is a novel process fur treatment of piggery waste with strong nitrogen. In this study, we investigated acid fermentation of organic matter, denitrificatiot reduction of sulfur compounds and P crystalization by hydroxyapatite during the treatment of wastewater with high strength of ammonium and organic matters by ANAMMOX process. Also, functions of hydroxylamine and hydrazine as intermedeates of ANAMMOX process were tested. This study reveals that various complex-reactions with anaerobic ammonium oxidation of piggery waste are happened and hydroxylamine and hydrazine play an important role in ANAMMOX reaction.

The Influence of Ammonium-Nitrogen on Anaerobic Microorganisms in Swine Wastewater by Batch-Fermentation. (혐기성 회분식 배양에서 양돈폐수의 NH$_4$-Nitrogen이 혐기성 미생물에 미치는 영향)

  • 김연옥
    • Microbiology and Biotechnology Letters
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    • v.26 no.2
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    • pp.173-178
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    • 1998
  • This study presents the influence of ammonium-nitrogen on microorganisms in swine wastewater. For the anaerobic batch fermentation, two different methods were used. One is the dilution of wastewater with water. The other method is the elimination of ammonium-nitrogen from the wastewater. By addition of MgO into wastewater, non-soluble crystall was formed under alkaline condition as MgNH$_4$PO$_4$6$H_2O$ (MAP). The master culture was adapted in swine wastewater for more than 3 months, in water-dilution method, the dilution of wastewater with 25% water gave us the best result in efficiency of COD removal. Two hundred hours later MAP-treated wastewater showed the efficiency of the COD removal more than 80%. Under same condition obtained none MAP-treated wastewater about 50%. MAP treatment carried out the very effective anaerobic digestion with swine wastewater. The important result in this study is that the low ratio of C:N influenced on anaerobic microorganisms more than high concentration of ammonium nitrogen in swine wastewater. The struvite for the crystallforming has no toxic effect on methanogenic bacteria.

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Cell-Recycled Continuous Ethanol Fermentation of Molasses (당밀의 균체순환식 Ethanol 연속발효)

  • 김익환;김병홍;민태익
    • Microbiology and Biotechnology Letters
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    • v.10 no.2
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    • pp.155-162
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    • 1982
  • A cell-recycled continuous fermentation process was studied to produce ethanol from molasses using Sacchoromyces uvarum ATCC26602 at 35 $^{\circ}C$. The fermentation system was divided into two stages in order to reduce the inhibitions of ethanol and substrate for cell growth and fermentation rate. The first reactor was aerated at the rate of 0.12 vvm whilst the second was kept anaerobic. In medium composition studies, it was revealed that inorganic nutrient supplement to the diluted molasses with 14% fermentable sugar was not needed for the fermentation, however, phosphate limitation was observed when cell propagation was contemplated. By using the cell-recycled continuous fermentation system, 14.5 hour was required to produce 8.4-9.0% (v/v) of ethanol from diluted molasses containing 14% of fermentable sugar. The ethanol productivity was 6.2g/$\ell$hr with the yield of 88.1-94.4% to the theoretical value.

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