ARS | Publication request: LIQUID HOT WATER PRETREATMENT OF ALFALFA FIBER DESTINED FOR ETHANOL PRODUCTION

Submitted to: ASAE Annual International Meeting
Publication Type: Proceedings
Publication Acceptance Date: August 13, 1997
Publication Date: N/A

Interpretive Summary: Much effort is currently being expended to produce renewable energy from plant materials to reduce our dependency on petroleum, a finite resource. Ethanol (alcohol) is a liquid fuel currently being produced mainly by converting the starch in corn to sugars which are then fermented to ethanol. A more sustainable raw material for ethanol, however, is the fibrous herbage of plants. These plant fibers are chains of sugars which can be fermented to ethanol if they can be broken down to individual molecules. Finding efficient ways to convert plant fibers to sugars is the key to ethanol production. A process investigated here is to treat the fiber with extremely hot water 430 deg F (220 deg C) for two minutes. The water is kept in the liquid state by holding it under high pressure. This treatment extracts about 60% of the plant dry matter. The resulting extract and solid residue can then be treated with enzymes to convert them into fermentable sugars. Development of efficient techniques for converting plant fiber to sugars for fermentation can be an important contribution to economical and renewable energy.

Technical Abstract: Alfalfa fiber derived from wet fractionation of fresh herbage was enzymatically saccharified and fermented with and without pretreatment. The liquid hot water (LHW) pretreatment consisted of flowing water kept in the liquid state by pressure, at 220 deg C through the fiber for two minutes. Yields of sugars and ethanol are compared.