Plant and waste material from agriculture or food industry represents on of the the worlds largest resources of ligno-cellulose and therefore fermentable sugars. Conversion of these sugars to ethanol is one way to take optimized profit of the solar energy incorporated in the plant growth. For the target product of ethanol of > 99.8 wt.%, there are several plant material sources available. The carbohydrate compounds of these materials can be pretreated and partly hydrolyzed by nearcritical water. CO2 dissolved in water may be used as catalyst. Hydrolysis is favorably accomplished by enzymatic catalysis. The product streams from the hydrolytic treatment are fermented. The resulting diluted ethanol solution is processed by multistage counter-current supercritical carbon dioxide extraction to ethanol of 99.8 wt.% concentration. Non-fermentable residues may be subjected to a second hydrolysis or transferred to a biogas production. Solid residues of the biogas reactor, in particular lignin containing fractions, can be oxidized with near and supercritical water to mainly gas and a smaller fraction of mainly short chain fatty acids, which can be reintroduced to the biogas reactor. (C) 2008 Elsevier B.V. All rights reserved.