Temperature as competitive strategy determining factor in pulse-fed aerobic bioreactors

Area of Science:

• Microbiology
• Biotechnology
• Environmental Science

Background:

• Microbial communities can be enriched for polyhydroxybutyrate (PHB) production using alternating carbon substrate availability under aerobic conditions.
• Understanding the factors influencing microbial competition and storage polymer accumulation is crucial for biotechnological applications.

Purpose of the Study:

• To investigate the role of temperature as a determining factor in microbial competition for intermediate storage polymer (PHB) production.
• To analyze how temperature affects microbial community structure and dynamics during PHB accumulation.

Main Methods:

• Operated eight parallel bioreactors across a temperature range of 20-40°C.
• Monitored PHB production and consumption, cell decay, and cryptic growth.
• Analyzed microbial community structure at different operational temperatures.

Main Results:

• Intermediate PHB production was observed only within the 25-35°C range.
• Cell decay and cryptic growth were significant factors influencing process properties and community structure across all tested temperatures.
• At 40°C, fast-growing microorganisms dominated due to inability to overcome decay with storage polymers.
• At 20°C, highly competitive communities with unclear storage properties were enriched.

Conclusions:

• Temperature is a critical factor, not independent, in determining microbial competition for PHB production.
• Microbial community structure and dynamics are significantly influenced by cell decay and cryptic growth, modulated by temperature.
• Rigorous experimental approaches are essential for understanding competitive strategies within microbial communities.