Microbiology of nitrogen cycle in animal manure compost

Hokkaido Research Subteam for Waste Recycling System, National Agricultural Research Center for Hokkaido Region, National Agricultural and Food Research Organization, 1 Hitsujigaoka, Sapporo 062-8555, Japan.
Microbial Biotechnology (Impact Factor: 3.21). 11/2011; 4(6):700-9. DOI: 10.1111/j.1751-7915.2010.00236.x
Source: PubMed


Composting is the major technology in the treatment of animal manure and is a source of nitrous oxide, a greenhouse gas. Although the microbiological processes of both nitrification and denitrification are involved in composting, the key players in these pathways have not been well identified. Recent molecular microbiological methodologies have revealed the presence of dominant Bacillus species in the degradation of organic material or betaproteobacterial ammonia-oxidizing bacteria on nitrification on the surface, and have also revealed the mechanism of nitrous oxide emission in this complicated process to some extent. Some bacteria, archaea or fungi still would be considered potential key players, and the contribution of some pathways, such as nitrifier denitrification or heterotrophic nitrification, might be involved in composting. This review article discusses these potential microbial players in nitrification-denitrification within the composting pile and highlights the relevant unknowns through recent activities that focus on the nitrogen cycle within the animal manure composting process.

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Available from: Koki Maeda
    • "Emissions of N 2 , NH 3 and N 2 O vary greatly from compost systems and can represent 2–90%, 6–80% and 2–6% of the N lost during composting, respectively (Brown et al., 2008; Eklind et al., 2007; Hellebrand and Kalk, 2001; Szanto et al., 2007). Production of N₂O can occur in both well aerated and oxygen-limited composts, due to different pathways and microorganisms being responsible for the emission (Maeda et al., 2011). Denitrification, a pathway occurring under anaerobic and limited oxygen conditions, is responsible for the reduction of 0956-053X/Ó 2015 Published by Elsevier Ltd. ⇑ Corresponding author at: SLU, Box 7032, SE-750 07 Uppsala, Sweden. "
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    ABSTRACT: Emissions of methane (CH₄) and nitrous oxide (N₂O) from composting of source-sorted food waste were studied at set temperatures of 40, 55 and 67°C in 10 trials performed in a controlled environment 200L compost reactor. CH₄ and N₂O concentrations were generally low. In trials with 16% O₂, the mean total CH₄ emission at all temperatures was 0.007% of the mineralized carbon (C), while at 67°C this fraction was 0.001%. Total CH₄ production was higher in the 40°C trial and the limited oxygen (1% O₂) trial, with emissions of 0.029 and 0.132% of the mineralized C respectively. An early increase in N₂O production was observed in trials with higher initial nitrate contents. Increased CH₄ and N₂O production in trials at 40 and 55°C after 50% of the initial C was mineralized resulted in higher total greenhouse gas emissions. Overall, the global warming potentials in CO₂-equivalents from CH₄ emissions were higher than from N₂O, except for composts run at 67°C. Copyright © 2015. Published by Elsevier Ltd.
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    • "). Even if some denitrifiers produce N 2 O as the final product of the denitrification process (Maeda et al., 2011), in general, this product is considered to be an intermediate product obtained, especially, in incomplete denitrification and its emission is reported in the range between of 0.2–9.9% of initial nitrogen content (Kuroda et al., 1996; Hao et al., 2001, 2004; Fukumoto et al., 2003; El Kader et al., 2007; Maeda et al., 2011; Maeda et al., 2013; Szanto et al., 2007, Tsutsui et al.; 2013). The emission of N 2 O from the plant was calculated extending the average emissivity of the active phases (29.76 mg NH 3 /m 2 h as reported in Table 3) to the entire surface of the plant and for the entire cycle. "
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    ABSTRACT: A full-scale composting plant (track type, aerated by screws), treating liquid swine manure (94.8% on mass basis) with straw (<0.8%) and sawdust (4.4%), was monitored. The main objectives were testing the performance of the process and assessing its environmental sustainability. Particular attention was dedicated to verify the possibility that this process could determine significant mass reduction, along with Nitrogen reduction, mainly by denitrification. Emissions were evaluated by measuring NH3, N2O and CH4 (by static chamber), H2S and odor emissions (by dynamic olfactometry). Quality and quantity of inputs and outputs and process parameters (redox, oxygen, and temperature) were monitored. The process produced a mature, highly humified (Humification Index=0.27), solid product with 92.8% mass reduction (mainly evaporation), and nitrogen reduction (85.8% referred to input TN). The process was revealed to be environmentally sustainable: emissions of odors and H2S resulted negligible; emissions of N-N2O represented 0.18% of TN input, while emissions of N-NH3 represented 0.87% of input TN. Microbiological analyses determined the presence of 10(7) CFU/g of bacteria related to N cycle and real time PCR demonstrated the presence in the final product of 4.77⋅10(7) couples of genes of Bacterial amoA/gTS and 2.46⋅10(7) couples NosZ/gTS, indicating nitrification and complete denitrification. These results exhibit that nitrification and complete denitrification can efficiently occur in a composting process effectively transforming N2O into N2 as consequence of the optimized alternation of aerated and anoxic phases in the feedstock. Copyright © 2015 Elsevier Ltd. All rights reserved.
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    • "7 ) . Nitrous oxide reductase is the enzyme which catalyses the final step in bacterial denitrification , the conversion of N 2 O to dinitrogen ( N 2 ) ( Zumft 2005 ) . The importance of this enzyme lies in its distinctive catalysis , a key process for N 2 O elimination from the biosphere that prevents the accumulation of a potent greenhouse gas ( Maeda et al . 2011 ) . However , most denitrifiers produce N 2 O instead of N 2 under aerobic conditions , because the N 2 O reductase is often ineffectual due to metabolically challenging conditions ( Sullivan et al . 2013 ) . In soils , this can have profound consequences since the escaped N 2 O is quickly released to the atmosphere . The N 2 OR from Ps"
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    ABSTRACT: As a stable greenhouse gas, nitrous oxide (N2O) plays a significant role in stratospheric ozone destruction. The primary anthropogenic N2O source is the use of nitrogen in agriculture. Currently, the annual N2O emissions from this soil-plant-microbial system is more than 2.6 Tg (1 Tg = 1 million metric tonnes) of N2O-N globally. So it is important to explore some innovative and effective biology-based strategies for N2O mitigation. If shown to be effective in field trails as well as laboratory-scale experiments, such GMO plants could help guide international policies on adaptation to climate change. The bacterial enzyme nitrous oxide reductase (N2OR) is the only known enzyme capable of catalyzing the final step of the denitrification pathway, conversion of N2O to N-2. To "scrub'' the N2O emissions, bacterial N2OR was heterologously expressed in plants. Structurally, the enzyme N2OR is encoded by nosZ, but its biosynthesis and assembly in prokaryotes require the products of several nos genes, including a putative ABC-type transporter encoded by nosDFY, and the copper chaperone NosL for biogenesis of the metal centre. We have generated transgenic tobacco plants expressing the nosZ gene, as well as tobacco plants in which the other nos genes were co-expressed under the control of a root-specific promoter (rolD) and a constitutive promoter (d35S). The nosZ gene from Pseudomonas stutzeri heterologously expressed in tobacco produced active recombinant N2OR. The positive results in the preliminary proof-of-principle experiments indicated that plants heterologously expressing N2OR could mitigate emissions at the source before N2O reaches the stratosphere or troposphere.
    Full-text · Article · Aug 2014 · Canadian Journal of Plant Science
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