[Methane fermentation of cattle manure at low temperature]

Area of Science:

• Microbiology
• Environmental Science
• Biotechnology

Context:

• Low-temperature fermentation of cattle manure is essential for methane production.
• Microbial community adaptation is a key challenge for low-temperature anaerobic digestion.
• Existing microbial associations often require long adaptation periods.

Purpose:

• To investigate the microbial community responsible for low-temperature cattle manure fermentation.
• To identify barriers to low-temperature methane production and methods to overcome them.
• To characterize psychrotrophic microorganisms involved in anaerobic digestion.

Summary:

• A microbial association for cattle manure fermentation at 6°C was developed through 2.5 years of autoselection.
• The primary barrier identified was the microbial community's adaptation period, which was overcome by adding psychrophilic yeast.
• Cultivating the psychrophilic methanogenic association at higher temperatures (35°C and 55°C) significantly reduced its activity.
• Kinetic analysis suggests significant property changes in the anaerobic microflora during low-temperature acclimation.
• Psychrotrophic microorganisms were found to be key players in organic matter degradation at low temperatures.
• Pure cultures of saccharolytic and acetogenic psychrotrophic bacteria, viable from 0°C to 35°C, were isolated.
• Methanosarcina and Methanothrix were detected in enrichment cultures utilizing acetate at 6°C.

Impact:

• Understanding microbial adaptation is crucial for optimizing low-temperature anaerobic digestion.
• The study highlights the role of psychrotrophic microorganisms in efficient low-temperature bioprocesses.
• Isolation of versatile psychrotrophic bacteria expands possibilities for low-temperature biotechnological applications.
• Findings contribute to the development of more efficient and sustainable methods for biogas production from manure.