Engineering ethanologenic Escherichia coli for levoglucosan utilization

Area of Science:

• Biotechnology
• Microbial Engineering
• Biomass Conversion

Background:

• Levoglucosan, a key product of biomass pyrolysis, is present in bio-oil.
• Commonly used microbial hosts like Escherichia coli cannot metabolize levoglucosan.
• Engineered levoglucosan kinase enables levoglucosan utilization as a carbon and energy source.

Purpose of the Study:

• To engineer an ethanologenic Escherichia coli strain for levoglucosan utilization.
• To enable the fermentation of levoglucosan into ethanol using a modified biocatalyst.

Main Methods:

• Recombinant expression of levoglucosan kinase from Lipomyces starkeyi in E. coli KO11.
• Codon optimization of the levoglucosan kinase gene.
• Chromosomal integration of the gene into the pyruvate to ethanol (PET) operon.

Main Results:

• The engineered E. coli strain successfully utilized levoglucosan as a sole carbon source.
• The modified strain fermented levoglucosan to produce ethanol.
• The genetic modification did not require additional antibiotics or inducers.

Conclusions:

• Existing biocatalysts can be readily engineered for levoglucosan metabolism.
• This work expands the utility of bio-oil components for biofuel production.
• Metabolic engineering provides a pathway for utilizing biomass pyrolysis products.