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Journal ArticleDOI

Methane production by mixed ruminal cultures incubated in dual-flow fermentors.

01 Jan 2004-Journal of Dairy Science (Elsevier)-Vol. 87, Iss: 1, pp 112-121
TL;DR: Dilution rate and forage-to-concentrate ratio altered the partition of substrate by microbes and underestimated methane output at higher dilution rates and with high forage diets.
About: This article is published in Journal of Dairy Science.The article was published on 2004-01-01 and is currently open access. It has received 70 citations till now. The article focuses on the topics: Dilution.
Citations
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Journal ArticleDOI
TL;DR: The different methods used to inhibit the H2-consuming bacteria are analyzed, such as biokinetic control, heat-shock treatment and chemical inhibitors along with their advantages/disadvantages for their application on an industrial scale.
Abstract: In this work, H2 production by anaerobic mixed cultures was reviewed. First, the different anaerobic microbial communities that have a direct relation with the generation or consumption of H2 are discussed. Then, the different methods used to inhibit the H2-consuming bacteria are analyzed (mainly in the methanogenesis phase) such as biokinetic control (low pH and short hydraulic retention time), heat-shock treatment and chemical inhibitors along with their advantages/disadvantages for their application on an industrial scale. After that, biochemical pathways of carbohydrate degradation to H2, organic acids and solvents are showed. Fourth, structure, diversity and dynamics of H2-producers communities are detailed. Later, the hydrogenase structure and activity is related with H2 production. Also, the causes for H2 production inhibition are analyzed along with strategies to avoid it. Finally, immobilized-cells systems are presented as a way to enhance H2 production.

347 citations

Journal ArticleDOI
TL;DR: In this article, the effects of three fibrolytic enzymes (xylanase from Trichoderma viride (XYL), endoglucanase from Aspergillus niger (ASP) and Trichodorma longibrachiatum (TR)) on the fermentation of three substrates composed of grass hay:

95 citations

Journal ArticleDOI
TL;DR: In this paper, the authors have shown that the use of nanoparticles in fermentation process along with the application of short and cyclic ultrasound is beneficial to increase the process efficiency and the augmentation in ultrasound-assisted process is due to the physical and chemical effects of ultrasound in the medium through the phenomenon of cavitation.
Abstract: The growing of food waste generation is gradually becoming a global problem due to the improper management of it. According to the Food and Agriculture Organization (FAO), United Nation, more than 1.3 million tonnes of food is being wasted. Food waste and food processing waste are abundant - which are rich in organic acids and nutrients. These acids and nutrients can be utilized for attractive and efficient generation of renewable and sustainable fuels such as biohydrogen through fermentation process. Many investigations have revealed a significant biohydrogen generation using food wastes from restaurant, dining hall and food processing industries. During the hydrogen generation through fermentation, several parameters influence the yield of hydrogen. Some of them are method of pre-treatment, feed composition, fermentation temperature, culture and substrate, solution pH, etc. Also, the presence of inert intermediates produced during the reaction in fermentation process reduces the process efficiency. Few studies have shown that the use of nanoparticles in fermentation process along with the application of short & cyclic ultrasound is beneficial to increase the process efficiency. The augmentation in ultrasound-assisted process is due to the physical and chemical effects of ultrasound in the medium through the phenomenon of cavitation. During the transient collapse of cavitation bubbles, several reactive species are produced which further participate in the thermochemical and biochemical reactions. Thus, enhances the rate of reaction by annihilation the complex sugars in food wastes. Additionally, the cavitational effect helps to reduce the growth of hydrogen inhibiting microorganism in the feed. This review demonstrates the potentiality of food waste for production of biohydrogen through fermentation process including a brief overview of process parameters that affect the fermentation process. Additionally, an overview of integrated fermentative process coupled with nanoparticles and ultrasound is also discussed for enhanced biohydrogen generation from food waste.

89 citations

Journal ArticleDOI
TL;DR: In this paper, a random coefficients model that used each study effect as a random variable was used to select statistically significant input variables to predict rate of passage for all classes of dairy and beef cattle.

75 citations


Additional excerpts

  • ..., 2004) and microbial growth (Eun et al., 2004; Owens and Goetsch, 1986)....

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Journal ArticleDOI
TL;DR: In this article, an in vitro gas production technique was used to measure total gas and methane (CH4) production from commercial total mixed rations (TMR) for lactating dairy cows.

73 citations

References
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12 Aug 1994

9,191 citations


"Methane production by mixed ruminal..." refers background or methods in this paper

  • ...The amount of substrate fermented to VFA, CH4, and CO2 was calculated based on the moles of individual VFA produced, daily methane output, and CO2 released from fermentation and buffer addition (Wolin, 1960; Van Soest, 1994; Blümmel et al., Journal of Dairy Science Vol. 87, No. 1, 2004 1997)....

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  • ...Increased lysis of microbial cells as a consequence of substrate exhaustion and uncoupled fermentation may contribute to reduced net growth at longer incubation times (Van Nevel and Demeyer, 1977)....

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  • ...Also, total gas yield can vary considerably due to the incorporation of carbons into microbial mass as well as the different metabolic pathways by which carbohydrate fractions can be degraded by rumen microbes (Krishnamoorthy et al., 1991; Beuvink and Spoelstra, 1992; Van Soest, 1994)....

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  • ...It is known that the growth yields of ruminal microbes can be relatively high, and that microbial cells have a negative oxidation-reduction state (Van Kessel and Russell, 1996)....

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  • ...Stoichiometric equations relating substrate degradation to VFA and gas production have been developed and are commonly used to estimate digestibility of ruminant feeds (Wolin, 1960; Russell and Baldwin, 1979; Menke et al., 1979; Van Soest, 1994)....

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Journal ArticleDOI
TL;DR: Linear regression equations have been obtained to directly calculate the nutrient requirements of dairy cattle (TDN, DE, ME, NEL,CP, Ca, P, Vitamin A and Vitamin D) on different physiological stages: maintenance, pregnancy and milk production based on NRC nutrient requirements tables.
Abstract: Linear regression equations have been obtained to directly calculatenutrient requirements of dairy cattle (TDN, DE, ME, NEL,CP, Ca, P, Vitamin A and Vitamin D) on differentphysiological stages: maintenance, pregnancy and milkproduction based on NRC nutrient requirements tables. TheR-square was calculated for each equation to establish thedegree of adjustment.

6,663 citations

Journal ArticleDOI
TL;DR: The Cornell Net Carbohydrate and Protein System has a submodel that predicts rates of feedstuff degradation in the rumen, the passage of undegraded feed to the lower gut, and the amount of ME and protein that is available to the animal.
Abstract: The Cornell Net Carbohydrate and Protein System (CNCPS) has a submodel that predicts rates of feedstuff degradation in the rumen, the passage of undegraded feed to the lower gut, and the amount of ME and protein that is available to the animal. In the CNCPS, structural carbohydrate (SC) and nonstructural carbohydrate (NSC) are estimated from sequential NDF analyses of the feed. Data from the literature are used to predict fractional rates of SC and NSC degradation. Crude protein is partitioned into five fractions. Fraction A is NPN, which is trichloroacetic (TCA) acid-soluble N. Unavailable or protein bound to cell wall (Fraction C) is derived from acid detergent insoluble nitrogen (ADIP), and slowly degraded true protein (Fraction B3) is neutral detergent insoluble nitrogen (NDIP) minus Fraction C. Rapidly degraded true protein (Fraction B1) is TCA-precipitable protein from the buffer-soluble protein minus NPN. True protein with an intermediate degradation rate (Fraction B2) is the remaining N. Protein degradation rates are estimated by an in vitro procedure that uses Streptomyces griseus protease, and a curve-peeling technique is used to identify rates for each fraction. The amount of carbohydrate or N that is digested in the rumen is determined by the relative rates of degradation and passage. Ruminal passage rates are a function of DMI, particle size, bulk density, and the type of feed that is consumed (e.g., forage vs cereal grain).

3,354 citations