Formic hydrogenlyase induction as a basis for the Eijkman fecal coliform concept

Area of Science:

• Microbiology
• Environmental Science
• Biochemistry

Background:

• Enterobacter species are common in aquatic environments.
• The Eijkman test historically uses gas production from lactose at 44.5°C to detect fecal coliforms.
• Understanding Enterobacter's biochemical capabilities is crucial for water quality assessment.

Purpose of the Study:

• To investigate the gas production capabilities of Enterobacter species from a freshwater stream.
• To determine if the formic hydrogenlyase enzyme system is responsible for gas production at elevated temperatures.
• To differentiate Enterobacter populations in aquatic environments based on their biochemical properties.

Main Methods:

• Isolation of Enterobacter species from freshwater samples.
• Incubation with glucose, lactose, and formate at 44.5°C.
• Analysis of evolved gas composition (CO(2) and H(2)).

Main Results:

• Most Enterobacter isolates produced gas from glucose, lactose, and formate at 44.5°C.
• The evolved gas consisted of carbon dioxide and hydrogen.
• These findings support the role of formic hydrogenlyase in the Eijkman test.

Conclusions:

• The enzyme formic hydrogenlyase is likely the basis for the Eijkman fecal coliform concept.
• Two distinct biochemical types of Enterobacter exist in aquatic environments: one with active formic hydrogenlyase at 44.5°C (soil/vegetation) and one without (intestinal tract).
• This differentiation aids in understanding microbial ecology and water contamination sources.