Researchers at the University of Toronto have identified how certain bacteria can be guided to turn waste into valuable industrial chemicals now largely sourced from palm oil.

The discovery could help create a more sustainable route to making medium-chain carboxylic acids, or MCCAs, a family of molecules used in cosmetics, cleaning products, agricultural feed, antimicrobials, and nutritional supplements.

Today, many of these chemicals come from palm kernel oil. Palm oil production has long faced criticism over links to deforestation, biodiversity loss, and weak supply-chain traceability.

The team says bacterial fermentation could offer an alternative by converting food waste and agricultural byproducts into high-value chemicals instead of relying on crops.

Waste into value

“The chemicals we are targeting here are known as medium-chain carboxylic acids (MCCAs) or medium-chain fatty acids (MCFAs),” said Professor Chris Lawson, who led the study.

“They are six to twelve carbon atoms long, and they are used in all kinds of things: agricultural feeds, cosmetics, antimicrobials, surfactants and much more. The global market for them is on the order of $3 billion.”

The researchers focused on chain-elongating bacteria, or CEBs. These microbes live without oxygen and can naturally convert organic material into useful acids through fermentation, a process similar to how yeast produces alcohol.

Because the bacteria can feed on waste streams rather than refined sugars, they may lower costs while reducing food-based inputs used in conventional bio-manufacturing.

Examples being explored include municipal food waste, such as material collected through Toronto’s Green Bin program, and byproducts from dairy processing.

But the microbes have one major drawback: they do not always make the most valuable product.

“What we want them to produce is octanoic acid, which is eight carbons long and one of the most high-value MCFAs, especially because palm kernel oil doesn’t contain that much of it,” Lawson said.

“But what we often find when we grow these CEBs is that they instead produce a less-valuable four-carbon molecule called butyrate.”

Decoding microbe switch

The new study explains what controls that switch.

Researchers found that the ratio of lactate to acetate – two compounds the bacteria consume – helps determine whether the microbes make longer-chain octanoic acid or shorter-chain butyrate.

They also identified the role of an enzyme called CoA transferase, or CoAT, which appears to separate bacteria that can make higher-value longer molecules from those that stop at four-carbon products.

“What we’ve shown is that in the bacteria that make the longer molecules, their CoA transferase is different,” Lawson said.

“It can act on precursors that are already six or eight carbons long.”

The findings could help engineers design bioreactors that consistently steer bacteria toward premium products instead of low-value outputs.

\The team is already moving beyond lab discovery. In separate work, researchers are developing genetic tools to push bacteria to produce even longer molecules and designing industrial systems to scale production.

Several members of the group have also launched a startup, SymBL Innovations, to commercialize the technology.

If successful, the process could give manufacturers a new source of ethically produced ingredients while reducing dependence on palm-based supply chains.

The study was published in Nature Microbiology.