Bio-ethanol is turning out to be a big business as it is considered one of the top alternatives to fossil fuel by many governments. But diversion of food sources to ethanol is a controversial issue as such an approach deprives humans of valuable food materials that can make a difference between destitution and decent life. Lately some efforts are being made to use other bio resources rich in cellulose for conversion to ethanol through mediation of cellulase enzyme system. What ever be the carbon source for alcohol fermentation, use of yeast under anaerobic condition generates large quantities of carbon dioxide (CO2) which are let out causing avoidable atmospheric pollution. CO2 is a valuable by-product, if properly harnessed, can be of considerable benefit to food industry. A country like the US continues to ignore the global plea for not diverting food crops and more than 40% of its corn production is expected to be used for the ethanol fuel program. Recent news that world's biggest Barley based industrial ethanol plant is about to be set up is a disturbing trend though the CO2 capture program, as a part of the project is welcome.
"Ethanol producer Osage Bio Products is to sell carbon dioxide by-products from its ethanol plant in Hopewell, Virginia, for use in the food industry. The firm has signed a 15-year deal to supply the otherwise wasted emissions to industrial gas supplier Praxair, Inc., from the fourth quarter of 2011. Praxair, which has its head office in Danbury, Connecticut, is planning to build a "world class facility" at the Hopewell site in order to capture and liquefy 450 tons of carbon dioxide a day. The firm is one of the largest industrial gas providers in the world, with $9 billion annual sales. Osage, which is backed by a $300 million investment from equity group First Reserve Corporation, is due to start up its Hopewell ethanol plant this August. Called Appomattox Bio Energy, the plant will be one of the first commercial-scale barley-to-ethanol processing plants in the US, producing 65 million gallons of ethanol each year. The agreement with Praxair will see carbon dioxide from the fermentation process provided for use in food freezing and processing applications, and also to beverage manufacturers".
CO2 is a vital ingredient of modified gas mixes that are used for preservation of perishable as well as durable foods, besides being an inert and bactericidal packaging aid in hermetically sealed food packs. Besides being amenable to liquefaction, it can also be compressed into "dry ice" for easy transportation and application. Dry ice has the property to sublime into gaseous phase without going through the liquid phase and this makes its use more practical, especially for small food processors. Many ethanol and breweries choose to let out the gas because of sustainable demand for the gas but if a deal like the above can be worked out there is no reason why alcohol plants will not invest on CO2 capture facilities and save this precious processing aid.