Name: how microbes produce methane
Uploaded: 2026-03-12T13:57:35.000Z
Duration: 1 min 26 s
Channel: JoVE

Em ambientes sem oxigênio, arqueias especializadas chamadas metanógenos realizam a metanogênese, produzindo metano como produto final de seu metabolismo energético.Compostos orgânicos de organismos mortos frequentemente afundam em zonas anóxicas, onde bactérias celulolíticas os decomponem em açúcares simples.Microrganismos fermentativos convertem esses açúcares em ácidos graxos de cadeia curta, como acetato, álcoois, hidrogênio e dióxido de carbono.Os metanógenos podem consumir diretamente acetato e hidrogênio e convertê-los em metano. Ao consumir hidrogênio, os metanogênios mantêm os níveis baixos de hidrogênio, permitindo que a fermentação continue.Bactérias sintróficas ajudam na decomposição de álcoois e outros ácidos graxos ao convertê-los em acetato, hidrogênio e dióxido de carbono.Os metanogênicos então usam esses compostos para produzir metano.Da mesma forma, no intestino dos cupins, microrganismos decompõem a celulose em açúcares. Protistas anóxicos fermentam esses alimentos em hidrogênio, que os metanógenos endossimbióticos consomem. Isso mantém os níveis de hidrogênio baixos, permitindo a fermentação contínua e a produção de acetato que os cupins absorvem para obter energia.

microborganismos e metanogênese

Microbes and Methanogenesis

A metanogênese é um processo microbiano crítico em ecossistemas anaeróbios responsável pela produção biológica de metano, um potente gás de efeito estufa e biocombustível valioso. Essa via metabólica é facilitada principalmente por arqueias metanogênicas, que prosperam em ambientes anóxicos como áreas úmidas, sedimentos e tratos gastrointestinais animais. A ausência de oxigênio nesses habitats impede a respiração aeróbica, favorecendo assim vias bioquímicas alternativas para a degradação da matéria orgânica.Nos estágios iniciais da decomposição anaeróbia, material orgânico complexo de organismos mortos passa por hidrólise por bactérias celulolíticas, liberando açúcares simples. Esses açúcares são então fermentados por outros microrganismos em uma variedade de metabólitos intermediários, incluindo ácidos graxos de cadeia curta como acetato, além de álcoois, hidrogênio (H₂) e dióxido de carbono (CO₂).A metanogênese ocorre quando os metanogênios utilizam esses produtos da fermentação, especialmente acetato e hidrogênio, para gerar metano (CH₄). A via hidrogenotrófica envolve a redução do CO₂ por H₂:CO2 + 4H2 → CH4 +2H 2OA metanogênese acetoclástica, outra via principal, converte acetato em metano e dióxido de carbono:CH3 COO− + H+→ CH4 + CO2A degradação de substratos mais complexos, como ácidos graxos de cadeia longa e álcoois, requer interações sintróficas. Sintróficos, como Syntrophomonas wolfei, produzem H₂, que os metanogênicos consomem para manter uma termodinâmica favorável ao processo.Nos intestinos de cupins, protistas anóxicos hidrolisam celulose, enquanto metanogênios endossimbióticos metabolizam o hidrogênio resultante para produzir metano. Por outro lado, bactérias acetogênicas usam glicose e compostos aromáticos para produzir acetato, uma fonte crucial de energia para o inseto hospedeiro. Essas redes microbianas ressaltam a importância ecológica da sintrofia e da cooperação metabólica na manutenção dos fluxos de metano provenientes de sistemas anaeróbicos.

Microborganismos e Metanogênese

Methanogenesis is a critical microbial process in anaerobic ecosystems responsible for the biological production of methane, a potent greenhouse gas and ...

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Education

JoVE Core

Microbiology

Microbiologia

Unit

Unidade

Microbial Ecology

Ecologia Microbiana

KEY TERMS AND CONCEPTS

TERMOS E CONCEITOS-CHAVE

how microbes produce methane

Methane production in anaerobic ecosystems depends on methanogenic archaea and the microbes that work with them. This process happens where oxygen is absent, such as wetlands, sediments, and animal gastrointestinal tracts. In these anoxic habitats, aerobic respiration cannot run, so microbes use other pathways to break down organic matter.

Anaerobic decomposition starts when cellulolytic bacteria, or cellulose-digesting bacteria, hydrolyze dead organic material into simple sugars. Other microbes then ferment those sugars into short-chain fatty acids such as acetate, plus alcohols, hydrogen (H2), and carbon dioxide (CO2). Methanogens use these fermentation products, especially acetate and hydrogen, to make methane (CH4).

Two major methanogenesis pathways are shown. In hydrogenotrophic methanogenesis, methanogens reduce CO2 with H2 to form methane and water. In acetoclastic methanogenesis, methanogens convert acetate into methane and carbon dioxide. Both routes help move carbon through oxygen-free environments.

More complex substrates, such as long-chain fatty acids and alcohols, require syntrophic interactions. Syntrophs are microbes that depend on partners to finish a metabolic job. For example, Syntrophomonas wolfei produces H2, and methanogens consume that hydrogen to keep the process thermodynamically favorable.

The transcript also shows this cooperation in termite guts. In these anoxic environments, protists break down cellulose, and endosymbiotic methanogens use the released hydrogen to produce methane. At the same time, acetogenic bacteria turn glucose and aromatic compounds into acetate, which serves as an important energy source for the host insect. These microbial partnerships show how methanogenesis supports methane flow in anaerobic systems.

How Microbes Produce Methane

introduction to microbial ecology

Microbial Communities in Soil and Extremes

Microbial ecology looks at how microorganisms live, interact, and adapt in different ecosystems. It also shows how these tiny organisms help shape nutrient cycling, energy flow, and environmental balance. An ecosystem includes living parts and non-living parts, and microbes respond to both. Microorganisms can form populations, which are groups of the same species living together at the same time. When populations from different species live and interact in the same place, they form a microbial...

ecological niche

Microbial Niches in Ecosystems

Microbial niches describe how microorganisms survive, grow, and interact in an ecosystem. A niche includes how a microbe gets resources, reproduces, and relates to other species in its environment. This idea helps explain microbial community dynamics, biogeography, and ecosystem function. A microorganism’s fundamental niche is the full range of conditions where it could survive, grow, and reproduce. These conditions include both biotic factors, such as living interactions, and abiotic factors,...

methods to assess microbial populations

Measuring Microbes in Samples

Measuring microbes in a sample helps scientists study health, ecology, and industry. Microbial counts can show how many cells are present, how diverse they are, and what they may be doing. To do this, researchers use both culture-based and molecular methods. A viable plate count is a classic culture method for estimating living microbes. The sample is first diluted step by step, then spread on nutrient agar plates. Each viable cell can grow into a visible colony, so the colonies can be counted.

methods to assess microbial communities

Measuring Microbial Diversity and Activity

Microbial communities include bacteria, archaea, and eukaryotic microorganisms. They live in many ecosystems and affect important environmental and biological processes. Scientists study these communities by looking at how many species are present, how many individuals each species has, and how evenly the species are spread out. Species richness is the number of different species in a sample. Species abundance is the relative amount of each species. Species evenness describes how uniformly the...

the winogradsky column

Microbial Layers Inside a Winogradsky Column

A Winogradsky column shows how microbial layers form in a simple, sealed ecosystem. It is a clear model for studying microbial ecology and how different metabolisms interact in sediment over time. The setup uses a transparent glass cylinder. Half of it is filled with sediment mixed with cellulose, such as shredded paper, calcium carbonate, and gypsum. The cellulose provides a carbon source. Calcium carbonate buffers pH, and gypsum supplies sulfate. The rest of the cylinder is filled with pond...

microenvironments

Microbial Niches in Tiny Habitats

Microorganisms live in tiny habitats called microenvironments. These spaces have their own physical and chemical conditions. Oxygen level, pH, temperature, light, and nutrient supply can all differ from the surrounding area. These local conditions strongly affect microbial growth, metabolism, and which species can live there. Microenvironments often have sharp gradients over very small distances. In soil, oxygen may be available at the particle surface but drop off just a few millimeters below.

microbial mats

Microbial Mats and Oxygen Gradients

Microbial mats are layered communities of microbes that grow in response to changes in light, oxygen, and nutrients. These ecosystems are highly organized, and different microorganisms live at different depths. Biofilms are the early stage of this growth and are only a few millimeters thick. Mature microbial mats can grow to centimeter scale and show clear vertical structure. This layered arrangement lets microbes fill separate niches within a very small space. In cyanobacterial mats from hot...

microbial interactions: mutualism

Mutualistic Partnerships in Nature

Mutualistic partnerships in nature show how two or more organisms can benefit from living together. These symbiotic relationships can be obligate, meaning the partners depend on each other, or facultative, meaning the association is helpful but not required. Mutualism helps support many ecosystem functions across land and water. One common example is the partnership between plant roots and mycorrhizal fungi, such as Rhizophagus species. The fungal hyphae grow into the root hairs and epidermis,...

microbial interactions: cooperation

Microbial Cooperation in Soil and Hosts

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microbial interactions: predation

How Microbes Hunt and Defend

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microbial interactions: competition

Microbial Competition and Niche Partitioning

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microbial interactions: parasitism

Microbial Parasites and Host Dependence

Microbial parasites depend on a host for nutrients and shelter, and this dependence often harms the host. In parasitism, only the parasite benefits. This is different from mutualism, where both organisms gain from the relationship. Microbial parasites are classified by where they live in or on the host. Ectoparasites stay on the host’s surface, such as the skin or outer tissues, and take in nutrients from outside. Endoparasites live inside the host’s body and invade tissues or organs.

microbe-plant interactions

How Plant Microbes Affect Growth

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microbes and the carbon cycle

How Microbes Move Carbon Through Earth

Microbes move carbon through Earth’s major reservoirs and help drive the carbon cycle. Carbon shifts among the biosphere, lithosphere, atmosphere, and hydrosphere, where it supports life and helps regulate climate. It commonly cycles as carbon dioxide (CO2), the oxidized form of carbon, but methane (CH4) and organic compounds also matter. Photosynthetic microbes take in atmospheric CO2 and turn it into organic carbon. Cyanobacteria are especially important because they carry out oxygenic...

microbes and methanogenesis

Methane production in anaerobic ecosystems depends on methanogenic archaea and the microbes that work with them. This process happens where oxygen is absent, such as wetlands, sediments, and animal gastrointestinal tracts. In these anoxic habitats, aerobic respiration cannot run, so microbes use other pathways to break down organic matter. Anaerobic decomposition starts when cellulolytic bacteria, or cellulose-digesting bacteria, hydrolyze dead organic material into simple sugars. Other...

microbes and the nitrogen cycle

Microbial Steps in the Nitrogen Cycle

Microbes drive the nitrogen cycle by changing nitrogen into forms that plants and other organisms can use. This biogeochemical cycle keeps nitrogenous compounds balanced in ecosystems. It also supports plant growth and microbial growth. Nitrogen fixation begins the cycle by converting inert atmospheric nitrogen gas, N2, into ammonia, NH3. This step depends on nitrogenase enzymes. Free-living diazotrophs do this on their own. Aerobic bacteria such as Azotobacter spp. and anaerobic bacteria such...

microbes and the sulfur cycle

Sulfur Cycling Through Microbial Reactions

Sulfur cycling depends on microbial reactions that move sulfur through rocks, water, soil, and the air. In Earth systems, sulfur shifts among inorganic forms such as sulfate, elemental sulfur, and sulfide. These changes happen through both abiotic processes and biological activity in oxic and anoxic environments. Sulfate is the most oxidized form of sulfur. It is stored mainly in rocks, marine sediments, and ocean water, where it acts as a long-term reservoir in the global sulfur cycle. In...

microbes and other elemental cycles

Microbes Driving Iron and Manganese Cycles

Microbes drive iron and manganese cycling in aquatic environments by changing these metals between reduced and oxidized forms. These reactions are especially important along redox gradients, where oxygen levels shift across stratified water layers. The microbes use these metals for energy, growth, and structural needs. In oxygen-rich surface waters, iron is usually present as insoluble ferric iron, Fe(III). Some bacteria release siderophores, which are small organic molecules that bind ferric...

marine microbial ecology

Microbial Life in the Ocean

Marine microbial life is shaped by salinity, low nutrients, and changing oxygen levels. These physical and chemical limits influence which microbes can survive and how they function. They also affect how ocean microbes help drive nutrient and carbon cycling. Small cell size is common in these environments because it gives microbes a larger surface-to-volume ratio. That helps them take up nutrients more efficiently when nutrients are scarce. In estuaries, where salinity changes often,...

deep sea microbial ecology

Deep Sea Microbes and Extreme Conditions

Deep sea microbes live in one of Earth’s harshest environments. The deep ocean is far below the sunlit photic zone, which usually reaches the upper 100 to 200 meters of open water. Below that layer, the bathypelagic and abyssal zones stretch from about 1,000 to 6,000 meters, and hadal trenches go even deeper. This region is dark, cold, and highly pressurized. Temperatures are usually around 2 to 3°C, although hydrothermal vents can be slightly warmer. Pressure rises by about 1 atmosphere for...

freshwater microbial ecology

Microbes in Streams, Lakes, and Rivers

Freshwater microbes live in streams, rivers, lakes, ponds, and marshes, but their communities change with water movement, light, depth, and nutrients. These systems are often grouped into lotic waters, which flow, and lentic waters, which are still or slow-moving. The physical setting shapes where microbes grow and how they get energy. In lentic systems, phytoplankton are the main producers. They make autochthonous organic carbon, which means carbon made within the water body. In lotic...

soil microbial ecology

How Soil Microbes Cycle Nutrients

Soil microbes drive nutrient cycling, organic matter turnover, and ecosystem stability. A gram of soil can contain thousands of bacterial and archaeal taxa, but their shared job is what helps sustain land ecosystems. Their activity changes the way carbon, nitrogen, and other nutrients move through soil. Soil is a patchwork of minerals, organic matter, water, and air. Microbes live in tiny microhabitats shaped by pore size, moisture, oxygen, and nutrients. Sandy soils drain fast and tend to...

key terms and concepts

Learn how methanogenic archaea, bacteria, and syntrophic partners break down organic matter and make methane in wetlands, sediments, and animal guts.

How Microbes Produce Methane | JoVE K12

JoVE Core Microbiology provides an engaging introduction to the microbial world and its influence on health, industry, and the environment. This comprehensive collection covers key concepts such as microbial structure, metabolism, genetics, and ecology. It introduces essential laboratory techniques and microscopy methods through visually engaging animations. Corresponding scientist-in-action videos bridge classroom concepts with real-world research and applications.

microbiology

How Microbes Produce Methane

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