What is a primary characteristic of facultative bacteria?

Facultative bacteria are characterized by their ability to utilize oxygen when it is available, but they can also survive in its absence by employing anaerobic metabolic processes. This adaptability allows these organisms to thrive in a variety of environments, making them integral to different ecological niches and various waste treatment processes.

For instance, in wastewater treatment, facultative bacteria play a crucial role in breaking down organic matter both in aerated and non-aerated conditions, which enhances the treatment efficiency and helps maintain a balanced microbial ecosystem. This inherent flexibility is what fundamentally defines facultative bacteria, distinguishing them from strictly aerobic bacteria, which require oxygen to survive, and strictly anaerobic bacteria that cannot tolerate oxygen at all.