What is the Difference Between Aerobic and Anaerobic Biodegradation

The key difference between aerobic and anaerobic biodegradation is that aerobic biodegradation occurs in the presence of oxygen, while anaerobic biodegradation occurs in the absence of oxygen.

Microorganisms break down organic matter into simpler forms, which can be absorbed by plants and other organisms. Therefore, they play an integral role in recycling matter in the environment. In fact, they are the main decomposers found in the soil. This process is named biodegradation, and it is a natural process. When biodegradation occurs, complex organic materials transform into water, carbon dioxide, minerals, and biomass. This process is very important for the balance of the natural environment. The rate of biodegradation depends on different factors; among them, the presence of oxygen is important. Depending on the oxygen requirement, there are two modes of biodegradation. They are aerobic biodegradation and anaerobic biodegradation.

CONTENTS

1. Overview and Key Difference
2. What is Aerobic Biodegradation
3. What is Anaerobic Biodegradation
4. Similarities – Aerobic and Anaerobic Biodegradation
5. Aerobic vs. Anaerobic Biodegradation in Tabular Form
6. FAQ – Aerobic and Anaerobic Biodegradation
7. Summary – Aerobic vs. Anaerobic Biodegradation

What is Aerobic Biodegradation?

Aerobic biodegradation is the type of biodegradation that occurs when oxygen is present. This is done by aerobic microorganisms. When an adequate supply of oxygen is available, aerobic microorganisms come into action and break down organic material into simple forms. It is a rapid method that degrades organic matter completely without producing pungent feasts. Many different types of organic pollutants are degraded by aerobic biodegradation. Aerobic microbes carry out cellular respiration in order to gain energy. It occurs using oxygen as the final electron acceptor.

When compared to anaerobic biodegradation, aerobic biodegradation is more effective for the removal of most organic pollutants. Most importantly, aerobes break down organic matter completely into non-toxic materials.

What is Anaerobic Biodegradation?

Anaerobic biodegradation is the breakdown of organic materials by microorganisms when oxygen is absent. Anaerobic microbes perform anaerobic biodegradation. This process occurs via a series of reactions. They are hydrolysis, acidogenesis, acetogenesis, and methanogenesis. Anaerobic degradation begins with hydrolysis, during which bacteria break down complex organic polymers into monomers. Then, the products formed after the hydrolysis are converted into non-gaseous short-chain fatty acids, alcohols, aldehydes, and gases during acidogenesis. Thirdly, those products will be converted into acetic acid, H_2, and CO₂ during acetogenesis. Acetogenesis provides substrates for methanogens to form methane and CO₂ during methanogenesis. During anaerobic biodegradation, methane and carbon dioxide are produced. This biogas is an alternative for energy. Moreover, this process can also produce hydrogen sulfide, ammonia, and hydrogen.

Anaerobic biodegradation is mainly used to treat wastewater sludge and biodegradable waste, including concentrated domestic wastewater, biosolids, animal manure slurry, and food processing wastes. This is because anaerobic biodegradation mainly involves volume and mass reduction of the waste. Anaerobic degradation mainly occurs in environments such as soils, sediments, and aquifers.

What are the Similarities Between Aerobic and Anaerobic Biodegradation?

• Aerobic and anaerobic biodegradation are two types of biodegradation.
• Microorganisms are involved with both aerobic and anaerobic biodegradation.
• They are mechanisms for reducing the complexity of compounds.
• Microbes carry out both types of degradation processes in the process of respiration and consumption of nutrients.
• Both processes produce non-toxic end products.
• They are oxidation-reduction mechanisms.

What is the Difference Between Aerobic and Anaerobic Biodegradation?

Aerobic biodegradation occurs when oxygen is present, while anaerobic biodegradation occurs when oxygen is absent. Thus, this is the key difference between aerobic and anaerobic biodegradation. Aerobes act during aerobic biodegradation, while anaerobes work during anaerobic biodegradation. Unlike aerobic biodegradation, anaerobic biodegradation produces pungent gasses. Most importantly, aerobic biodegradation is more effective, rapid, and completely degrades organic matter. In contrast, anaerobic biodegradation is slow and time-consuming.

The infographic below presents the differences between aerobic and anaerobic biodegradation in tabular form for side-by-side comparison.

FAQ: Aerobic and Anaerobic Biodegradation

What is the difference between aerobic and anaerobic organisms?

The main difference between aerobic and anaerobic organisms is their oxygen requirement. Aerobic organisms need oxygen for their survival, while anaerobic organisms can grow and survive without oxygen.

What are the 4 stages of anaerobic degradation?

The four stages of anaerobic biodegradation are hydrolysis, acidogenesis, acetogenesis, and methanogenesis.

What are the products of aerobic biodegradation?

CO2, water, biomass, and carbon residue are the products of aerobic biodegradation.

Summary – Aerobic vs. Anaerobic Biodegradation

Biodegradation is a natural process mainly performed by microorganisms. Microbes break down complex organic polymers into simple monomers when oxygen is present and in some microbes when oxygen is absent. Based on oxygen availability, aerobic biodegradation occurs by aerobes when oxygen is present, while anaerobic biodegradation occurs by anaerobes when oxygen is absent. Unlike anaerobic biodegradation, aerobic biodegradation does not produce pungent gasses such as methane and hydrogen sulfide. So, this summarizes the difference between aerobic and anaerobic biodegradation.

Reference:

1. Sikora, Anna, et al. “Anaerobic Digestion: I. A Common Process Ensuring Energy Flow and the Circulation of Matter in Ecosystems. II. A Tool for the Production of Gaseous Biofuels.” IntechOpen, IntechOpen, 8 Feb. 2017.
2. Liu, Fei DouYundang WuChuanping, et al. “Biodegradation.” Springer, Springer Netherlands.

Image Courtesy:

1. “Slime.mold” By Red58bill – Own work (CC BY 3.0) via Commons Wikimedia