Tercer Seminario regional agricultura y cambio climático:
nuevas tecnologías en la mitigación y adaptación de la
agricultura al cambio climático
Arqueas metanógenas en al mitigación del
cambio climático en la agricultura
Flávia Talarico Saia
Chemistry Institute, Universidade Estadual Paulista Júlio de Mesquita Filho –
UNESP, Araraquara, SP, Brazil
Email: ftsaia@yahoo.com.br
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CH4 as a source of energy
Intergovernmental pane
l on climate change (IPCC), 2007
METHANE
19th century
anthropogenic
Anaerobic treatment of waste
Methane concentration in the atmosphere
CH4
Recovered and used
clean
Fonte: NASA/Goddardas
Space
Flightenergy
Center
Methane to Market
CH4 as a greenhouse gas
Methane has global warming
potential (GWP) 21-25 times
more than CO2
Methane accounts for about
20% of global warming
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• Mitigation strategies for methane emissions
• Use of methane as a energy source
• Sources of methane emission
• Methanogenic microorganisms
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THEY ARE THE ONLY MICROORGANISMS KNOWN THAT PRODUCE METHANE
Methanogenesis:
The Process
Anaerobic condition
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 multi-step process carried out by different
groups of microorganisms
1. Hydrolytic Bacteria
2. Fermentative Bacteria
3. Acetogenic Bacteria
4. Methanogenic Archaea
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Hydrogenotrophic
H2, formate
Acetoclastic
Acetate
Methanobrevibacter
Methanosaeta
Methilotrophic
Methanol
Methanosarcina
• It is important for carbon cycle since methanogenesis prevents a build-up of organic matter,
allowing the other microorganisms to support the oxidation of substrates
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Hydroeletric
Rice fields
wetlands
Landfill
WHERE ARE METHANOGENIC ARCHAEA ?
Methanogens are ubiquitous in anoxic
environments
Anaerobic digesters
Livestock - cattle
Termites
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Agriculture - source of methane
Major sources of methane emissions:
• Agriculture : In 2010 accounted for 53% of global methane emission
• Energy: oil and natural gas systems
• Waste: solid waste and wastewater treatment
Yusulf et al. (2012) Renewable and Sustainable Energy Reviews
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Agriculture sectors
• Manure: stored or treated in liquid system
- Top emmiting counties:
U.S., Germany, India, China, France,
Russia, Turkey and Brazil.
Yusulf et al. (2012) Renewable and Sustenaible Energy Reviews
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Agriculture - CH4 emissions
in Brazil
Agriculture sectors
glogster.com
Other sectors
4%
Coal mining
8%
Enteric
Fementation
22%
Manure
Management
7%
Biomass
11%
Landfills
10%
Wastewater
Treatment
7%
greencleanguide.com
Agriculture
accounting for 45% of
CH4 emission
Rice
cultivation
16%
novotempo.com
Oil gas
15%
Largest beef exporter in the world
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Vinasse – liquid waste from ethanol
Sugarcane
Ethanol
Vinasse
Vinasse has been used as fertilizer to sugarcane fields
•Emission of methane during storage of vinasse
• Emission of N2O from soil
Brazil is the largest producer of sugarcane ethanol in the world and immense volume
of vinasse is generated – 10L vinasse/L ethanol
In 2006/2007, 190 billions of liters of vinasse were produced
Rego e Hernández (2006); Oliveira (2011); Carmo et al., 2012
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Brazilian authorities announced that the country
will target a reduction in its GHG between
36.1 and 38.9% from projected 2020 levels.
The Intergovernmental Panel on Climate Change - IPCC (2007)
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Mitigation Strategies: Enteric Fermentation
• CH4 is not only GHG but it is also a waste of fed energy for
the animal
•Large number of MA are in the ruminal liquid: 107 to 109 cells/mL
(Kamra, 2005).
 Hydrogenotrophic methanogens: Methanobacteriales,
Methanomicrobiales, Methanosarcinales have been found
Methanobrevibacter smithii
Methanobacterium formicicum
Methanosarcina barkeri
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microbewiki
Enteric Fermentation – mitigation strategies (MS) to methane
emission
MS target the methanogens of the rumen directly or indirectly
• Diet Composition: use of easy degradable carbohydrate – reduce pH in the rumen –
decreases MA. However, accumulation of organic acids can occur, leading to subacute
ruminal acidosis (SARA) and disruption of the rumen microbiota (Plaizier et al., 2008).
• Lipids: Fatty acids and oils (Johnson and Johnson, 1995; Hook et al., 2010).
- inhibition of protozoa which supply methanogens with hydrogen
- Increase the production of propionic acid - it is not used for methanogens
- Binding to the cell membrane of methanogens and interrupting
membrane transport
• Defaunation: decrease the number of protozoa by the use of copper, sulphate, acids,
(Hook et al., 2010)
• Vaccines: target methanogens directly (Wedlock et al., 2010)
Hook et al. (2010)
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Enteric Fermentation – mitigation strategies (MS) to
methane emission
• Other strategies: selection of high quality grasses, increase grain level and
increasing feed conversion efficiency to produce meat and milk
 Researches have shown:
• MS are limited by the diet feed, the management conditions, physiological
condition, use of the animal, and government laws.
• Long-term experiments in vivo need to be done to implement MS
• Economic viability of the producer needs to be addressed
Brazil: diversty of methahogens related with diet – hay proportions (Neves et al., 2010)
improvement of meat production related with sugarcane feeding in dry season
(Primavesi et al., 2003)
Hook et al. (2010); Yusuf et al., 2012
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Rice fields
CH4 is produced by anaerobic
degradation of organic matter
that occurs in soil and also in
roots
CH4 oxidation by
methanotrophic
bacteria
Anaerobic CH4 oxidation
www1.ethz.ch
MS = net methane emission
Phillipot et al. (2009), Dubey (2005)
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• Acetoclastic but mainly hydrogenotrofic methanogens
Methanolinea
Methanobacterium kanagiense
Sakai et al., 2012
Kitamura et al., 2011
Methanoculleus chikugoensis
Dianou et al., 2011
• Methanotrophic bacteria
Methylomonas koyamae sp
Adachi et al 2001
Methylosinus
Ogiso et al., 2011
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Mitigation Strategies: Rice field
• Mitigation strategies include:
- reduction of methane production; increasing methane oxidation,
lowering methane transport through the plant
• Selection of cultivars with low exudation rates
• To keep the soil as dry as possible in the off- rice season : adverse environmental
condition for methanogenesis
• Use of fertilizer: ammonium nitrate and sulphate instead of urea
Current information is insufficient for the development of technology
and strategy for reduction in methane emission
To improve the knowldgement of methanogens and
methanotrophic bacteria in soil and in roots
Phillipot et al. (2009),
Dubey (2005) 18
Mitigation Strategy: anaerobic treatment of manure and vinasse
Aim: to apply anaerobic technology to
PRODUCE METHANE for BIOENERGY
PURPOSES
Land applications
(N, K, P)
pathogenic
microorganisms
Methane has a high energy value (ΔHo= 816 kJ/mol or 102 kJ/e- eq)
that can be captured through combustion and used for space heating or eletricity
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• Studies
have been carried out to better understand the anaerobic
process in order to control the process and achieve optimum biogas yield
Support medium
Configuration of reactors
UASB
Polyhurethane foam
HAIB
• Effect of inhibitory substances:
ammounium, salt content,
sulphate, temperature
Lettinga (1980)
Foresti et al. (1995)
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Microorganisms – biodigestors treating manure slurries
• Methanosarcinaceae and Methanobacteriales are predominant in
anaerobic reactors treating different kinds of manure
• Due to high levels of ammonium, pointig out the importance of
hydrogenotrophic methanogenesis (Netmman et al., 2010)
Methanosarcina
Methanomicrobium
Methanobrevibacter
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Microorganisms – biodigestors treating vinasse
• Acetoclastic and hydrogenothrophic methanogens
Methanosarcina
microbewiki
Methanomicrobium sp
bacmap.wishartlab.com
Methanosaeta
Araújo et al. (2003)
• Termophilic process – vinasse is produced at high temperatures (80-900C)
Souza et al. (1992); Viana (2006); Ribas (2006)
- sludge stable among harvests
- It is necessary to decrease temperature
- process is faster than mesophilic
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Hydrogen and methane production
Use of two -stage bioreactors to produce hydrogen and methane
Vinasse
Acidogenic
reactor
H2 and acids production
Peixoto et al. (2012)
Methanogenic
reactor
Consumption of acids and
production of methane
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Conclusions
 Emissions of methane from agriculture activities are a
worlwide problem, mainly regarding enteric fermentation, rice
field and manure managment
 In Brazil: contribution of vinasse used as fertilizer
 Studies have shown that there are mitigation strategies,
however a better understanding of the microorganisms, the
factors affecting symbiotic relation with other microbial
population and their environment, also long term expriments
are needed to implement MS
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Brazil
• Studies focused on microbial diversity:
Amazon and Pantanal
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Muchas gracias
Flávia Talarico Saia
ftsaia@yahoo.com.br
55 16 33019506
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