US firms Calysta Energy and NatureWorks have entered into an exclusive, multi-year collaboration to research and develop a practical, world-scale production process for fermenting methane — a potent greenhouse gas (GHG) — into lactic acid, the building block for NatureWorks’s Ingeo lactide intermediates and polymers made from renewable materials. If the collaboration results in the successful commercialisation of this first-of-its-kind technology, the cost to produce Ingeo would be structurally lowered, and the wide range of Ingeo based consumer and industrial products could be produced from an even broader set of carbon-based feedstocks, complementary to what is already in use by NatureWorks.

A greenhouse gas 20 times more harmful than carbon dioxide, methane is generated by the natural decomposition of plant materials and is a component of natural gas. Methane is also generated from society’s organic wastes and is produced from such activities as waste-water treatment, decomposition within landfills and anaerobic digestion. If successful, the technology could directly access carbon from any of these sources. Determining the feasibility of methane as a commercially viable feedstock for lactic acid may take up to five years, according to NatureWorks.

“If proven through this R&D collaboration, the new technology could be revolutionary because it will provide alternatives to the current reliance on agricultural feedstocks, and with the direct conversion of methane, it will greatly simplify the number of steps and operations needed to convert carbon into performance consumer products,” said Marc Verbruggen, President/CEO of NatureWorks. “This could structurally lower the cost of producing Ingeo.”

Currently, Ingeo relies on carbon from CO₂ feedstock that has been fixed or sequestered through photosynthesis into simple plant sugars, known as “first generation materials.” NatureWorks’ flagship facility in Nebraska uses industrially sourced corn starch, while its second facility currently in planning for a location in Southeast Asia will use cane sugar. In parallel with the collaboration, NatureWorks is continuing its broad technology assessment of “second generation” cellulosic sources of carbon. In the case of Southeast Asia, opportunities exist for harvesting cellulosic sugars from bagasse, an abundant lignocellulosic byproduct of sugarcane processing.

The R&D collaboration with Calysta Energy relates to NatureWorks strategic interests in feedstock diversification and a structurally simplified, lower cost Ingeo production platform. Calysta Energy is developing its BioGTC (biological gas-to-chemicals) platform for biological conversion of methane to high value chemicals. For NatureWorks, methane could be an additional feedstock several generations removed from simple plant sugars.

The project will wrap up with an evaluation of potential sources of a methane feedstock for commercial scale production of lactic acid. The evaluation will include criteria such as purity, availability, price, location to customers, GHG sequestration potential and environmental and energy impacts. Feedstock diversification supports the organisation’s goal of utilising the most abundant, available and appropriate sources of carbon to produce Ingeo for the local geographic region served by a NatureWorks’ production facility.

NatureWorks is jointly owned by Thailand’s largest chemical producer, PTT Global Chemical, and Cargill, an international producer and marketer of food, agricultural, financial, and industrial products and services.