Difference Between Autochthonous and Zymogenous Bacteria

The key difference between autochthonous and zymogenous bacteria is that autochthonous bacteria are native or indigenous microorganisms that grow and metabolize under scarce nutritional resources while zymogenous bacteria are a group of bacteria that require easily oxidizable organic materials for growth.

There are two types of soil bacteria based on nutritional differences: autochthonous bacteria and zymogenous bacteria. Autochthonous bacteria are native or indigenous bacteria that are found in high numbers in the soil. They can grow in soil which contains a limited source of energy. Generally, their number in the soil does not fluctuate. They are uniformly spread in soil. In contrast, zymogenous bacteria need easily oxidizable organic materials for growth. Once high energy-containing nutrients are added, they show a rapid growth. Their number in soil fluctuates frequently. However, zymogenous bacterial population in the soil is low compared to autochthonous bacteria.

CONTENTS

1. Overview and Key Difference
2. What are Autochthonous Bacteria
3. What are Zymogenous Bacteria
4. Similarities Between Autochthonous and Zymogenous Bacteria
5. Side by Side Comparison – Autochthonous vs Zymogenous Bacteria in Tabular Form
6. Summary

What are Autochthonous Bacteria?

Autochthonous bacteria are native or indigenous soil bacteria that grow deriving foods from native soil organic matter. They don’t need an external energy source. Autochthonous bacterial population in the soil is high and uniform. The population does not fluctuate in response to nutrient availability.  They grow and metabolize under scarce nutrient resources. Hence, they are mostly found in soil that has limited resources.

Autochthonous bacteria are also known as k-strategists. Caulobacter crescentus and Escherichia coli are two examples of autochthonous bacteria.

What are Zymogenous Bacteria?

Zymogenous bacteria are a group of soil bacteria that require easily oxidizable substrates for their growth. They are actively fermenting forms of bacteria. They need an external source of energy. Once it is provided, they show a rapid growth and rapidly increase to great numbers.

When the added nutrient level decreases, they return to undetectable numbers. Therefore, zymogenous bacterial population fluctuates greatly unlike autochthonous bacteria in response to the availability of nutrients. However, zymogenous bacteria occur in low numbers in the soil. Methylomonas, Nitrosomonas, Pseudomonas aeruginosa, Nitrospira and Nitrobacter species are several zymogenous bacteria.

What are the Similarities Between Autochthonous and Zymogenous Bacteria?

• Autochthonous and zymogenous two types of soil bacteria based on nutritional differences.
• They are decomposing microorganisms in the soil.

What is the Difference Between Autochthonous and Zymogenous Bacteria?

Autochthonous bacteria are native soil bacteria that are uniformly spread and relatively constant throughout the soil. In contrast, zymogenous bacteria are the second group of soil bacteria that require easily oxidizable substrates to grow. So, this is the key difference between autochthonous and zymogenous bacteria. Autochthonous bacteria are numerous in the soil, while the presence of zymogenous bacteria is transient.

Moreover, another significant difference between autochthonous and zymogenous bacteria is that autochthonous bacterial population does not fluctuate while zymogenous bacterial population fluctuates greatly.

The below infographic tabulates the differences between autochthonous and zymogenous bacteria.

Summary – Autochthonous vs Zymogenous Bacteria

Autochthonous bacteria are uniformly spread in soil, and their population does not fluctuate. In contrast, the presence of zymogenous bacteria is transient in soil, and their population greatly fluctuates in response to nutrient availability. Autochthonous bacteria can grow under limited resources. But, zymogenous bacteria need external energy resources or easily oxidizable organic substrates for their growth. Autochthonous bacteria are also known as k-strategists while zymogenous bacteria ate known as r-strategists. Thus, this summarizes the difference between autochthonous and zymogenous bacteria.

Reference:

1. Boheme, Livia. “Classification of Soil Microorganisms Based on Growth Properties: a Critical View of Some Commonly Used Terms.” Research Gate, 2004. Available here.

Image Courtesy:

1. “Caulobacter crescentus” (Public Domain) via Commons Wikimedia
2. “Pseudomonas aeruginosa SEM” By Janice Haney CarrContent Providers(s): CDC/ Janice Haney Carr – This media comes from the Centers for Disease Control and Prevention’s Public Health Image Library (PHIL) (Public Domain) via Commons Wikimedia