According to the Kyoto agreements the total CO₂-emissions in the industrialised nations need to be reduced by 5% in 2010 as compared to the 1990 level. In the longer term, a reduction of more than 50% is required to stabilise the CO₂-level in the atmosphere. A major strategy to achieve these objectives is the large-scale substitution of petrochemical fuels and products by CO₂-neutral alternatives derived from biomass. Large-scale application of the fermentation products bioethanol as a renewable transport fuel and lactic acid in renewable packaging materials (polylactic acid, PLA) can make a substantial contribution to this strategy.

Use of biomass as feedstock for bioethanol and lactic acid production
Bioethanol and lactic acid are currently produced by fermentation of sugars derived from corn, sugar cane and sugar beet. The relatively high costs of these agro-feedstocks form a major obstacle for large-scale application of bioethanol and lactic acid. The use of lignocellulosic biomass and residues as feedstock will increase the production volume and simultaneously reduce production costs. This applies in particular for widely available, low-cost residues from agriculture, agro-industry and forestry, and bio-wastes such as the organic fraction of municipal waste and roadside grass. These biomass streams are primarily composed of lignocellulose, a complex fibrous structure of the sugar polymers cellulose and hemicellulose, which is strongly intermeshed with the aromatic co-polymer lignin. Both the cellulose and hemi-cellulose fractions are a potential source of fermentable sugars. For this purpose the sugars must be released from the complex fibrous biomass by means of physical/chemical and enzymatic methods. In the consecutive fermentation process, the available sugars must be converted to bioethanol or lactic acid with high efficiency. Non-fermentable residues from the process –mainly lignin– can be used for thermal conversion generating power and heat for the production process and surplus electricity for delivery to the grid. Bioethanol can be applied in blends with fossil transport fuels, while lactic acid can serve as a feedstock for production of polylactic acid (PLA) to replace petrochemical packaging materials such as PET.

Technology development
The industrial use of lignocellulose materials as a source of sugars for fermentation processes still requires considerable R&D. The international efforts in the past decades have thus far not resulted in a technology applicable at industrial scale. In the Netherlands a 4-year R&D project (2002-2007) is underway with the objective to develop technologies for the use of lignocellulose as a raw material for bioethanol and lactic acid production. The project –supported by the Economy, Ecology and Technology Programme– is a co-operative effort of the industries Purac biochem B.V., Royal Nedalco B.V. and Shell Global Solutions International B.V. and the R&D institutes ECN, Agrotechnology & Food Innovations B.V., Wageningen University Dept. of Agrotechnology and Food Sciences, TNO Environment, Energy and Process Innovation and TNO Nutrition and Food Research.

The preparation of fermentable sugars from lignocellulose is a major challenge. This requires integral optimisation of the trajectory from feedstock through fermentation, as addressed in this project. Major R&D themes in the project are:

• Physical/chemical pre-treatment for the mobilisation of (hemi)cellulose from the lignocellulose matrix.
• Optimisation of enzymatic cellulose hydrolysis with commercially available industrial enzymes.
• Application of lignocellulose hydrolysates for ethanol and lactic acid fermentation. Prevention of formation of inhibiting side products and fermentation of C5 sugars are major issues.
• Power and heat production from non-fermentable biomass fractions and process integration with specific attention for optimal energy integration and reduction of water use.
• Application of bioethanol in blends with fossil fuels.

Economy and ecology
The European Commission has recently issued the “Concept Biofuels Directive” in order to promote the substitution of fossil transport fuels by biofuels. The objective is to reach a substitution level of 2% in 2005, 5.75% in 2010 and 8% in 2020. If 25% of these EU targets are met through bioethanol this would imply an additional market volume of 2,500 million Euro per year and a reduction of CO₂-emissions in the transportation sector by 18 Mtonnes/year. Replacing petrochemical packaging materials (e.g. PET) and other chemicals (such as solvents) by (poly)lactic acid could generate an additional EU market volume of 760 million Euro/year and a CO₂-reduction of approximately 11 Mtonnes/year.