Bioproducts from renewable methanol: The paraformaldehyde approach

Area of Science:

• Biotechnology and Industrial Microbiology
• Sustainable Chemistry

Background:

• Renewable methanol is a key feedstock for producing single-cell protein (SCP) and circular chemicals.
• Current biotechnological approaches using methanol are not economically viable at large scales due to high oxygen demands.

Purpose of the Study:

• To introduce a novel feedstock, paraformaldehyde, to reduce oxygen requirements in methanol-based bioproduction.
• To demonstrate the feasibility of using paraformaldehyde for microbial metabolism.

Main Methods:

• Paraformaldehyde was synthesized from methanol.
• Three methylotrophic microbes were tested for their ability to metabolize formaldehyde released from paraformaldehyde.
• A stirred-tank bioreactor was used to assess formaldehyde levels during microbial fermentation.

Main Results:

• Paraformaldehyde slowly releases formaldehyde at ambient temperatures.
• Methylophilus methylotrophus maintained formaldehyde below detection limits over a 20-hour fermentation.
• Three methylotrophic microbes successfully metabolized formaldehyde from paraformaldehyde.

Conclusions:

• Paraformaldehyde is a suitable, less-reduced feedstock for large-scale production of SCP and circular chemicals from renewable methanol.
• This approach significantly reduces the oxygen footprint of methanol fermentation.
• Paraformaldehyde offers a viable alternative to direct methanol utilization in industrial biotechnology.