Current Uses of Synthetic Biology

Isoprene is an important commodity chemical used in a variety of applications, including the production of synthetic rubber. Isoprene is naturally produced by nearly all living things (including humans, plants and bacteria); the metabolite dimethylallyl pyrophosphate is converted into isoprene by the enzyme isoprene synthase. But the gene encoding isoprene synthase has only been identified in plants such as rubber trees, making natural rubber a limited resource.

Currently, synthetic rubber is derived entirely from petrochemical sources. Genencor®, a Division of Danisco U.S. Inc., together with The Goodyear Tire & Rubber Company, is currently working on the development of a reliable, high-efficiency fermentation-based process for the BioIsoprene™ monomer, and synthetic biology has played an important role in making this undertaking a reality.

Although plant enzymes can be expressed in microorganisms through gene transfer, it is a long and cumbersome process, as plant genes contain introns and their sequences are not optimized for microorganisms. DNA synthesis and DNA sequencing have enabled the construction and rapid characterization of metabolically engineered microorganism strains to produce isoprene. Synthetic biology has enabled the construction of a gene that encodes the same amino acid sequence as the plant enzyme but that is optimized for expression in the engineered microorganism of choice. This method has provided massively parallel throughput which has made it possible to identify and track genetic variation among the various strains, providing insights into why some strains are better than others.

Continued use of synthetic biology should help refine Genencor’s biocatalyst for the production of BioIsoprene™ monomer.

Delivering Economic, Renewable BioAcrylic

Acrylic is an important petrochemical used in a wide range of industrial and consumer products. Acrylic ingredients make paints more durable and odor-free, adhesives stronger and longer-lasting, diapers more absorbent and leak-proof, and detergents better able to clean clothes. Today, petroleum-based acrylic is an $8 billion global market.

OPX Biotechnologies (OPXBIO) is developing renewable bio-based acrylic to match petro-acrylic performance but with lower cost and an 85 percent reduction in greenhouse gas emissions. BioAcrylic from OPXBIO also will reduce oil-dependence and offer more stable prices.

The key to realizing these benefits, as with any bio-based product, is a highly productive and efficient microbe able to use renewable sources of carbon and energy (for example corn, sugar cane, or cellulose) in a commercial bioprocess. A microbe that meets these criteria for BioAcrylic has not been found in nature, so OPXBIO is applying its proprietary EDGE™ (Efficiency Directed Genome Engineering) technology to redesign a natural microbe to achieve these goals. With EDGE, OPXBIO rapidly defines and constructs comprehensive genetic changes in the microbe to optimize its metabolism for low-cost production of BioAcrylic.

OPXBIO is already producing BioAcrylic at pilot scale in advance of opening a demonstration plant in 2011 and a full-scale commercial plant in 2013. OPX has a commercial target of 50 cents per pound for BioAcrylic production costs to match the industry standard for petroleum-based acrylic.

Making “Green Chemicals” From Agricultural Waste

Surfactants are one of the most useful and widely sold classes of chemicals, because they enable the stable blending of chemicals that do not usually remain associated (like oil and water).

Today, nearly all surfactants are manufactured from either petrochemicals or seed oils, such as palm or coconut oil. Worldwide production of surfactants from petrochemicals annually emits atmospheric carbon dioxide equivalent to combustion of 3.6 billion gallons of gasoline. Production from seed oil is greener, but there is a limit to the amount of seed oil that can be produced while protecting the rainforest. To address this problem, Modular has developed microorganisms that convert agricultural waste material into useful new surfactants. Dr. P. Somasundaran of the University Center for Surfactants (IUCS) at Columbia University finds that Modular’s surfactant is 10-fold more effective than a similar commercially available surfactant.

M. Pete He, PhD., Senior Research Fellow, Corporate Sustainability, Dial, Henkel of America says: “Sustainable chemistry will be a major driver of U.S. economic growth, and I look forward to more of this type of impressive work, which is a win-win, combining academic achievement with industrial implications.”

Modular has developed an engineered microorganism that converts soybean hulls into a surfactant that can be used in personal care products and other formulations. The hull is the woody case that protects the soybeans, and it cannot be digested by humans or other monogastric animals, such as pigs. The U.S. produces about 70 billion pounds of indigestible soy carbohydrate annually, and Modular seeks to upgrade this underutilized material by converting it into a variety of useful new chemical products. Modular’s surfactant program is partially supported with funds from the New Uses Committee of the United Soybean Board (USB), which seeks to expand soybean markets through the development of technology that enables the conversion of soy-based materials into new products.