Today, bulk chemicals are typically produced from petroleum resources. As fossil fuel sources are limited, costly and emits greenhouse gases, renewable resources are being investigated as
Various types of biomass resources can be transformed into valuable chemicals. Particularly the use of organic wastes is interesting because they are cheap and abundantly available feedstock that contains sufficient organic material for easy bioconversion. Through fermentation processes short chain carboxylates such as acetate, propionate and butyrate can be produced and used as bulk chemicals in industry. The main problem of fermentation of organic waste is that the versatile composition of organic compounds leads to a combination of fermentation products in various amounts. The major outcomes of this Ph.D. study showed that (1) mixed culture fermentation can be steered towards a single major fermentation product (2) integration of in-situ product recovery into the fermentation process increase the yield of a total carboxylate production.