CH391L/S13/Metabolic Engineering and Thermophiles

Metabolic Engineering

Metabolic Engineering is the changing and optimization of metabolic pathways in an organism for the increased production of a chemical product. This can include the addition of enzymatic steps catalyzed from enzymes encoded by exogenous genes. With economically viable feedstocks metabolic engineering has become a relevant process by which companies can create sustainable chemicals and pharmaceuticals.

Metabolic engineering was first done by chemical mutagenesis of organisms and screening for organisms with increased production of the desired metabolite. Eventually, with increased knowledge of metabolic pathways and genetic engineering techniques in the 1990s the constraints on a metabolic pathway and production of a desired metabolite could be more easily relieved[2]. Modern techniques combine genetic engineering, systems biology, and directed evolution to improve yields in metabolic engineering. A particularly valuable systems biology technique called flux balance analysis, which is "a mathematical method for simulating metabolism in genome scale reconstructions of metabolic networks," has been particularly useful (Example). Bernhard Palsson, an innovator in systems biology, co-founded a metabolic engineering company based on on flux balance analysis [3]

Examples of Metabolic Engineering

• Pharmaceuticals - Arteminisin
• Petrochemical Replacements - BDO and PDO
• Biofuels - [4]

Government and Metabolic Engineering

The U.S. Department of Energy (DOE) through the Bioenergy Technologies Office is heavily involved in research and funding of metabolic engineering projects for biofuels and bioproducts [5]. Their website is a good reference for the basics of the field [6].

Biomassfeedstocks, products, and applications [1]

Thermophiles

Organisms on earth are found to live between temperatures of −15°C to 122°C. Thermophiles are a type of extremophile that like to live in high temperature. Thermophiles are broken down into two groups "obligate' thermophiles (require high temperatures for growth) and faculative thermophiles (can live at high or low temperatures). Thermophiles are best known in biology as the source for the enzymes used in PCR, these orgasnims were isolated in hot springs and deep sea hydrothermal vents.

Terms for organisms based on their temperature preference

• Psychrophile grow down to −15°C to +10°C
• Mesophile grow typically between 20 and 45 °C
• Thermophile grow between 45 and 122 °C
• Hyperthermophile optimal temperatures are above 80°C