Even though biofilms are the most common form of bacterial growth in Nature, industrial fermentations rely almost entirely on planktonic lifestyle. Biofilms, however, offer several advantages to be exploited in fermentation processes. Bacteria in biofilms are more tolerant to several stresses as compared to free (i.e. planktonic) cells, including toxic chemicals and shear stress. The adhesion of bacteria to a surface can be used to operate continuous processes without excessive loss of biomass, thereby facilitating downstream processing. We are implementing synthetic biology approaches to control the formation of biofilms during fermentation. By merging the fields of contemporary synthetic biology and classical biofilm fermentation, we will harness the full potential of catalytic bacterial biofilms for biosynthesis of fine chemicals. As part of these activities, we manipulate the formation of biofilms, both spatially and temporally, through the use of genetic sensors and circuits and novel expression systems tailored for P. putida. These approaches are complemented by engineering novel biochemistries for the biosynthesis of fine chemicals in special cultivation setups designed for catalytic biofilms.