BIO-BASED VALUE-ADDED ALPHA-OLEFINS

Researchers at The Center for Biorenewable Chemicals (CBiRC), an NSF-funded Engineering Research Center headquartered at Iowa State University, recently showed that medium chain length free fatty acids can be produced by E.coli using sugars as the carbon source. The research uses codon-optimized eukaryotic and prokaryotic enzyme sources expressed in the microbial systems. The projects reported 35-40% of the theoretical yields with 2.7g/L being attained, comparing very favorably with recent literature reports. Further improvements are underway with strain optimization, media optimization and fine-tuning of the operating conditions. Similar studies are underway in yeast systems using similar enzyme sources along with additional optimization and characterization. Simultaneously, in parallel research projects the toxicity of such short chain fatty acids is being evaluated. This research combines flux map analysis and newly developed bioinformatic "network component analysis" tools for systemwide analysis and allows insights into the compensatory mechanisms being perturbed in such biological systems.

These studies are enabling CBiRC to drive the construction of its metabolic engineering design engine and hence make new strains for high level fatty acid and polyketide synthesis in microbes. The projects bring together faculty from Iowa State University as well as the University of Califorina - Irvine, Rice University, the Salk Institute and the University of Michigan.

Medium chain fatty acids are important as a stepping stone to creating even shorter fatty acids in the future. These medium and shorter chain fatty acids can form a foundation for making α-olefins using other chemical catalysis methods under development in CBiRC. Such α-olefins are part of the larger family of olefins or alkenes with a chemical formula CxH2x. Polymerization of alkenes yields polymers that are known in a general way as polyolefins. The α-olefins are distinguished by having a double bond at the primary or α-position, which enhances the reactivity of the compound and makes it useful for a number of applications. Olefins are reactive intermediates used to manufacture products used in plastics, lubricants, surfactants, agricultural chemicals, coatings and corrosion inhibitors. Such olefins are synthesized today from petrochemical sources and can have high industrial value. The research reported above begins to set-out a new path to making biorenewable or bio-based olefins.

To learn more about this topic visit: Center for Biorenewable Chemicals (CBiRC)

NEW BUILDING FOR INTERDISCPLINARY WORK IN BIORENEWABLES

The new Biorenewables Research Laboratory (BRL) at Iowa State University is the university's hub for biorenewables research. Completed in 2010, the four-floor, 70,000-square-foot facility is the first phase of a planned three-wing complex, bringing together three primary research organizations under one roof: the NSF Engineering Research Center for Biorenewable Chemicals (CBiRC), the Bioeconomy Institute, and the Biobased Industry Center. The building was funded through a $32 million legislative appropriation, includes chemistry and microbiology labs for research, two large teaching laboratories, administrative and faculty offices and graduate student office areas. It also features a two-story "high bay" facility for larger, pilot-scale research projects in thermochemical biomass conversion. The university plans second phase expansion of the building once sufficient funding has been secured.

The building incorporates cost-saving, eco-friendly design elements that should qualify it for LEED gold certification. During construction 97 percent of construction waste was recycled with only 3 percent of the debris directed to landfills. Building materials were specified to contain the maximum amount of pre- and post-consumer recycled content. Over 30 percent of the total building materials consist of recycled content. Because building materials can change many hands and travel great distances, a Chain of Custody form was completed for virtually every material that made its way to this project. This ensured that much of the materials came from within a 500 mile radius and were collected in a sustainable manner. Wood used in the building frame is documented from the forest, to the lumber mill, to our supplier, to our site. The same was done for metals, concrete and other materials.

The orientation of the building captures southern exposure and the resulting daylight. Incredibly, 92 percent of the spaces within the building enjoy direct exterior views. In addition to natural lighting, the building uses recyclable building materials such as the doors and cabinetry made from bamboo. The building is also equipped with a rainwater collection and storage system, and a portion of the structure has an energy-saving vegetated roof. Overall water consumption is reduced by 75 percent because of these measures. The lighting systems throughout the building utilize occupancy sensors and compact fluorescent lighting (CFLs) to make full use of natural light and to drastically reduce our need for electricity. The offices and public spaces are air conditioned by a system called a chilled beam. Chilled beams use chilled water in a series of coils that then have ducted air pushed through the coils. It uses less energy to run chilled water than conditioned air and saves money with smaller air duct work required. This is the first time this system has been used in the state of Iowa. The surrounding landscape is a combination of native prairie plantings and adaptive vegetation, which once established, will not require watering. The site also incorporates switch grasses that are examples of biomass utilized in research programs.

To learn more about this topic visit:  Center for Biorenewable Chemicals (CBiRC)

ARRAY OF BIORENEWABLE CHEMICALS

Researchers at The Center for Biorenewable Chemicals (CBiRC), an NSF-funded Engineering Research Center headquartered at Iowa State University, are studying multiple enzymes involved in the fatty acid and polyketide pathway, including: 3-ketoacyl-ACP Synthases, Acetoacetyl-CoA Synthetases, Acetyl-CoA/Propionyl-CoA Synthetases, Acyl-CoA Carboxylases, Methylketone Synthases, Thioesterases, Biocatalysts of the Acetyl-CoA Condensation, Fatty Acid Elongases, Biotin (cofactor). As part of this work, CBiRC is using data-mining techniques to find amino acid sequences and tertiary structures of members of the seven enzyme groups that make up the fatty acid/polyketide synthesis cycle and include them in a major database. The new constantly updated ThYme (Thioester-active enzYmes) database contains primary and tertiary structures, classified into families and clans that are different from those currently found in the literature or in other databases. Researchers are arranging these members into families unrelated to each other by sequence similarity. The families are grouped into clans related by tertiary structure and mechanism. Furthermore, the families are divided into subfamilies by differences in their sequences. This allows an intimate understanding how enzymes produced by different organisms having the same substrate specificities are related to each other. Using this database along with biochemical studies of enzyme kinetics and specificities allows CBiRC to visualize ways of selecting and even engineering novel optimized enzymes.

Collectively these studies are enabling CBiRC to drive the incorporation of novel enzymes into its metabolic engineering design engine and hence make new strains synthesizing novel fatty acid and polyketides in microbes. The projects bring together faculty from Iowa State University as well as the Salk Institute and the University of Michigan.

The fatty acid and polyketide pathway enzymes are important because they are the biological catalysts that synthesize the building blocks for novel bio-based chemicals. Thus CBiRC envisions that these enzymes, when appropriately engineered, will create a foundation for delivering an array of novel molecules having longer and shorter chains, branched and ring structures as well as more functionalized molecules. These biocatalysis efforts are focused on the fatty acid or polyketide biosynthetic pathway which will be combined with chemical catalysis to create an array of novel chemical intermediates (e.g., olefins, diols, dienes, branched and ring structures, ethers and esters). These chemical intermediates will be used in a new chemical industry to make an array of bio-based materials ranging from polymers to surfactants, food additives to cosmetics, adhesives to paints, coatings, dyes, sealants and specialty chemicals. CBiRC envisions multiple applications of these new bio-based materials, resulting in the displacement of today's petrochemical sources of such high-value materials.

To learn more about this topic visit:  Center for Biorenewable Chemicals (CBiRC)