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Alternative Fuels: Retooled Approach May Make Bio-based Butanol More Competitive With Ethanol

Date:
November 15, 2008
Source:
USDA/Agricultural Research Service
Summary:
A modified method of producing biobutanol could make the fuel more competitive with ethanol as a clean-burning alternative to gasoline.
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FULL STORY

ARS researchers have modified a method of producing biobutanol that could make the fuel more competitive with ethanol as a clean-burning alternative to gasoline.
Credit: Photo by Peggy Greb

A modified method of producing biobutanol could make the fuel more competitive with ethanol as a clean-burning alternative to gasoline.

According to Agricultural Research Service (ARS) chemical engineer Nasib Qureshi, biobutanol offers several advantages. It can be transported in existing pipelines, it's less corrosive, it can be mixed with gasoline or used alone in internal combustion engines, and it packs more energy per gallon than ethanol.

Until the mid-20th century, biobutanol was produced from fermented sugars such as corn glucose. But low yields, high recovery costs and petroleum's increased availability after World War II sidelined fermentation-based systems for biobutanol production.

Today, petroleum price increases have rekindled interest in tapping butanol as a biobased fuel, notes Qureshi, with the ARS National Center for Agricultural Utilization Research in Peoria, Ill. In 2003, he began researching the use of wheat straw to make biobutanol—drawn by the straw's abundance and promise as a lower-cost alternative to corn-glucose-based feedstocks.

Like other biobutanol processes, his approach employed Clostridium bacteria to carry out the critical task of fermentation. Such processes normally involve four preparatory steps (pretreatment, hydrolysis, fermentation and recovery) carried out separately and sequentially. But Qureshi and colleagues devised a way to combine three of the four steps. For example, enzymes and the bacteria are allowed to carry out their respective tasks simultaneously. Throughout, a procedure known as "gas stripping" is used to extract the biobutanol as it is produced.

In early trials, the method increased biobutanol productivity by twofold above traditional glucose-based fermentation. A later adjustment, dubbed "fed-batch-feeding," increased production even further. For example, during a 22-day fed-batch operating period, a culture of C. beijerinkcii P260 converted nearly 430 grams of sugar into 192 combined grams of acetone, biobutanol and ethanol.

If scaled up further, the process could yield 99 gallons of these three chemicals from one ton of wheat straw.


Story Source:

The above story is based on materials provided by USDA/Agricultural Research Service. Note: Materials may be edited for content and length.


Cite This Page:

USDA/Agricultural Research Service. "Alternative Fuels: Retooled Approach May Make Bio-based Butanol More Competitive With Ethanol." ScienceDaily. ScienceDaily, 15 November 2008. <www.sciencedaily.com/releases/2008/10/081031212844.htm>.
USDA/Agricultural Research Service. (2008, November 15). Alternative Fuels: Retooled Approach May Make Bio-based Butanol More Competitive With Ethanol. ScienceDaily. Retrieved April 25, 2015 from www.sciencedaily.com/releases/2008/10/081031212844.htm
USDA/Agricultural Research Service. "Alternative Fuels: Retooled Approach May Make Bio-based Butanol More Competitive With Ethanol." ScienceDaily. www.sciencedaily.com/releases/2008/10/081031212844.htm (accessed April 25, 2015).

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