Abstract
Biomass can be considered as renewable energy source, and can be converted, into either direct energy or energy-carrier compounds, by direct combustion, anaerobic digestion destructive distillation, gasification, chemical hydrolysis and biochemical hydrolysis. Biomass such as forest, agricultural and animal residues and industrial and domestic wastes can now be converted by physical-chemical and/or fermentation processes to clean fuel such as bioethanol. Lignocellulosic biomass also can be converted to ethanol by hydrolysis and subsequent fermentation. In hydrolysis, the cellulose part of the biomass is converted to carbohydrates (sugars), and fermentation converts these carbohydrates to bioethanol.
The paper presents some contributions regarding the monitoring, by measuring the variation of some specific biochemical parameters (carbohydrates, amino acids and enxymes concentration and acidity index), the anaerobic conversion of biomass wastes in order to obtain biofuel bioethanol.
The indirect advantages using ethanol instead of gasoline are reductions in their contributions to global warming and the addition of anhydrous ethanol to gasoline eliminates the need for tetra-ethyl lead to raise the octane rating. Studies have shown that ethanol-powered engines produce 57% less carbon monoxide, 64% less hydrocarbons and 13% less nitric oxides than gasoline-powered vehicles. The world price of ethanol is still about twice that of oil, and fuel consumption is also up to 20% heavier with alcohol. However, these economic considerations are changing in favour of “green” petrol production, with future anticipated increasing oil prices and new design concepts for alcohol-based engines.
Keywords: biofuels, bioethanol, recycling, biomass wastes, sawdust