Development of a mixed culture chain elongation process based on municipal solid waste and ethanol

Keywords: mixed culture fermentation; Carboxylates; Caproate; Heptanoate; ethanol; OFMSW

To reduce dependence on oil, alternative fuel and chemical production processes are investigates. In this thesis, we investigated the production of medium chain fatty acids (MCFAs) using an anaerobic chain elongation process from the organic fraction of municipal solid waste (OFMSW) and (diluted) ethanol.By using OFMSW for the production of MCFAs, OFMSW can be valorised. Moreover, the food-fuel discussion can be avoided, as long as the ethanol is not produced from food resources. Investigations included studies about single stage and two-stage systems, methods to reduce impact of competitive processes within the desired mixed microbial culture and kinetic considerations. As result, the MCFA productivity was improved more than 100-fold compared to the productivity at the start of the investigations. Consequently, the potential of the mixed culture chain elongation process as alternative for anaerobic digestion has increased.