Corn-based ethanol production

High energy and water demands in some processes, eg, corn-based ethanol production... 

By 2020, the EU wants to have 10% ethanol in its transportation fuel, and China is aiming for 15%. The United States Senate is proposing a biofuel production target of 36 billion gallons by 2020, of which 21 billion would come from corn-based ethanol. As a result, com prices doubled (from 1.65 to 3/bushel), and the number of ethanol plants also nearly doubled (from 81 to 129). 

The farm industry supports the production of corn-based ethanol, although the food industry opposes it, because the increased demand for corn is raising the cost of animal feed and, therefore, the cost of dairy, poultry, and other products. 

Subsidizing the production and use of corn-based ethanol for motor fuel attempts to hide the perverse result of consuming more overall energy than does using oil-based gasoline. Furthermore, the politically directed diversion of corn from food to fuel has caused... 

There is a need for continued increases in yields not only to feed a growing world population, but also for greater fuel production (OECD-FAO, 2007). For example, US ethanol production, predominately based on corn, is expected to double between 2006 and 2016 (Figure 1.1). By 2016, ethanol is expected to represent a full one-third of corn production. Corn used for fuel in China is expected to increase from 3.5 million tons in 2006 to 9 million tons in 2016 (Figure 1.2). Ethanol production in Brazil is predominately based on sugarcane and is expected to increase by 145% between 2006 and 2016 (Figure 1.3). 

In America, partly in response to the energy crisis of the 1970s, Congress instituted federal ethanol production subsidies in 1979. Corn-based grain ethanol production picked up quickly, and federal subsidies totaled about 11 billion through 2006. 

For the last 70 years or so the chemical industry has been based on crude oil (petroleum) and natural gas as basic raw materials, hence the name petrochemicals. This may not be so for much longer, however. The chemical industry is currently on the brink of a new revolution, based on the switch from fossil resources to renewable agriculture-based raw materials. From a distance the production facility of Cargill in Blair, Nebraska looks very much like a small oil refinery or medium-sized petrochemicals plant. However, closer inspection reveals that it is a corn-processing plant a biorefinery producing, inter alia, high-fruc-tose corn syrup, ethanol and lactic acid. As James R. Stoppert, a senior executive of Cargill pointed out, the chemical industry is based on carbon and it does not matter if the carbon was fixed 2 million years ago or 6 months ago [1]. 

Mechanism and kinetics in biochemical systems describe the cellular reactions that occur in living cells. Biochemical reactions involve two or three phases. For example, aerobic fermentation involves gas (air), liquid (water and dissolved nutrients), and solid (cells), as described in the Biocatalysis subsection above. Bioreactions convert feeds called substrates into more cells or biomass (cell growth), proteins, and metabolic products. Any of these can be the desired product in a commercial fermentation. For instance, methane is converted to biomass in a commercial process to supply fish meal to the fish farming industry. Ethanol, a metabolic product used in transportation fuels, is obtained by fermentation of corn-based or sugar-cane-based sugars. There is a substantial effort to develop genetically modified biocatalysts that produce a desired metabolite at high yield. 

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