Developing Lactic Acid Bacteria for the conversion of brown macroalgae into green chemicals and fuels

Microbial conversion of biomass plays a major role in establishing a bio-based economy, which aims at replacing fossil resources with renewable substrates for the production of fuels and chemicals. Current efforts in using non-edible (‘second generation’) biomass rather than food-derived sugars focus on lignocellulosic materials such as crop residues and non-edible plants.

However, lignin is often toxic to the production organism and hard to eliminate, and economically feasible conversion of cellulose and hemicellulose is still challenging. An attractive alternative includes brown macroalgae or sea weed, which do not contain lignin, do not require fresh water, are not a major food source, and contain a higher sugar fraction.

The main sugars are mannitol, laminarin (glucose) and alginate (guluronate and mannuronate). We will use metabolic engineering and laboratory evolution of Lactic Acid Bacteria (LAB) for the conversion of brown macroalgae into green chemicals and fuels. To select the best-suited production platform, we are screening Lactobacillus and Pediococcus strains for traits like genetic accessibility, substrate utilization and several stress tolerances.

Most microorganisms, including LAB, do not naturally utilize alginates and hence the introduction of these pathways will be the first step in engineering the selected strain, after which further efforts will focus on co-utilization of the different sugar fractions and establishment of product pathways.