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Nov 01, 2024

A low-cost method for bio-based production of acrylic acid - Chemical Engineering | Page 1

November 1, 2024 | By Mary Page Bailey Acrylic acid, a commodity chemical used widely in superabsorbent polymers, paints, coatings, adhesives and more, is typically produced from fossil-based

November 1, 2024 | By Mary Page Bailey

Acrylic acid, a commodity chemical used widely in superabsorbent polymers, paints, coatings, adhesives and more, is typically produced from fossil-based propylene at relatively high temperatures. As part of an initiative supported by the U.S. Dept. of Defense, funding was recently awarded to Industrial Microbes, Inc. (iMicrobes; Alameda, Calif.; www.imicrobes.com) towards commercializing a new bio-based manufacturing process for acrylic acid that reduces both the cost and carbon footprint (diagram). “We are using the support to plan our first commercial facility that will use a fermentation process to convert ethanol into acrylic acid and derivatives,” says Noah Helman, iMicrobes CEO. The company has engineered microorganisms to consume plant-based ethanol as a carbon and energy source. Within a proprietary engineered bacterial cell, an intermediate polymer (a polyester of 3-hydroxypropionate, or P3HP) is readily accumulated as fermentation takes place. “That polymer can be converted to acrylic acid via a very simple catalytic cracking process. With heating to a moderate temperature, the catalyst decomposes the polymer into acrylic acid vapors, which can be captured and purified using standard unit operations like distillation,” says Helman.

In June, iMicrobes began scaling up the process at a facility in Emeryville, Calif., operating at the kilogram scale for the first time outside of the laboratory. “Then, in August, with support from BioMADE, we began operating that same process in a 1,500-L fermenter at a site in Illinois, generating several more kilograms of product,” adds Helman.

The key to the process’ efficiency is the accumulation of the intermediate polymer, which is generated at very high concentrations inside the bacterial cell. “In our cost modeling, we estimate that we should be able to produce acrylic acid at about 20% lower cost than today’s existing methods, and the carbon footprint should be reduced by 75% or even more, depending on the source of the ethanol,” says Helman.

The first applications for iMicrobes’ acrylic acid products will be in consumer personal-care products, where bio-based raw materials carry a particular premium, and the company is also looking at routes to additional products beyond acrylic acid.