The use of bio-ethanol as fuel reduces the emission of greenhouse gases such as CO2. Bio-ethanol has so far mainly been produced from sugar cane and corn starch and has therefore competed with the production of food and fodder. Although difficult in technical terms, ethanol can also be produced from lignocellulose, e.g. wood. In the current biotechnological procedure, the biomass is initially thermochemically treated. In the next step, the enzymes split the cellulose into monosaccharides, which is then fermented into ethanol by microorganisms. This process needs to be strongly simplified and made more cost-efficient, however, before it can be used commercially.
The research work focuses on a simplified, integrated process for producing ethanol from pre-treated lignocellulose. In a multi-species biofilm membrane reactor (MBM reactor), the enzymes are produced, the hemicelluloses and cellulose saccharified, the resultant monosaccharides fermented and the ethanol ultimately separated. It is, however, difficult to transform lignin-rich wood into ethanol biotechnologically. For this reason, the researchers are expanding the microbial consortium used with lignin-degrading fungi strains to see whether the yield and reaction rate can thereby be improved and the energy consumption at the pre-treatment stage reduced.
Climate policy and resource economy offer good reasons for increasing the share of renewable fuels made from lignocellulose. The simple MBM procedure has the potential to produce ethanol sustainably, efficiently and decentrally in a forested or agricultural environment with short transport routes for the required biomass.