Work scheme to isolate the different micro-organisms found in hydrogen-producing reactors: a study of effectiveness...

Area of Science:

• Microbiology
• Biotechnology
• Environmental Science

Background:

• Hydrogen-producing reactors are crucial for sustainable bioenergy.
• Understanding microbial communities within these reactors is vital for optimizing hydrogen production.
• Effective isolation techniques are needed to study these complex microbial consortia.

Purpose of the Study:

• To develop and validate a comprehensive work scheme for isolating diverse microorganisms from hydrogen-producing reactors.
• To assess the effectiveness of the proposed isolation scheme against advanced sequencing methods.
• To identify key microbial players involved in the hydrogen production process.

Main Methods:

• Development of selective methods for isolating anaerobic spore-forming fermenters, non-spore-forming anaerobic fermenters, facultative aerobic fermenters, and lactic acid bacteria.
• Application of the developed methods to samples from a cheese whey-fed hydrogen-producing reactor.
• Comparison of isolated microbial genera with pyrosequencing data (16S rRNA gene sequences) to determine isolation efficiency.
• Confirmation of hydrogen-producing capabilities of isolated strains and coculture experiments to study microbial interactions.

Main Results:

• The isolation scheme successfully recovered over 88% of microbial abundance detected by pyrosequencing.
• Key genera isolated include Clostridium, Rahnella, Megasphaera, Lactobacillus, Propionibacterium, Bifidobacterium, Chryseobacterium, and Acetobacter.
• Clostridium, Rahnella, and Megasphaera isolates demonstrated hydrogen-producing capacity.
• Megasphaera was found to mitigate the inhibitory effect of Lactobacillus on Clostridium in coculture experiments.

Conclusions:

• The proposed work scheme is effective for isolating a majority of microorganisms present in hydrogen-producing bioreactors.
• The study highlights the high culturability of microbial communities in these systems.
• Physiological studies using these isolates can provide crucial insights into the biohydrogen production process, with Megasphaera playing a significant role.