The concept of circular economy is based on our capacity to Reduce, Reuse and Recover resources. Resource recovery requires a complete reorganization of waste treatment, which is mainly based on resource dissipation (denitrification, combustion, landfilling, etc.). Resources recovery from biological waste treatment strategies is a currently very active field of research (Puyol et al., 2017), and PPB should play a major role in this socioeconomic revolution. Purple phototrophic bacteria (PPB) have extensively been studied and implemented in axenic pure-culture systems to produce biohydrogen, bulk chemicals, and value-added products like polyhydroxyalkanoates (PHAs), fertilizers, cosmetic and food supplements, etc. The versatility of PPB is now becoming more widely harnessed in the academic community, resulting in the development of new environmental biotechnology practices that use mixed-culture PPB bioprocesses to treat and convert complex used streams like wastewater or agro-industrial waste into clean water and added-value products. In addition, PPB have evolved into a biophysical paradigm due to the very high efficiency of their light-collecting machinery.
Furthermore, the photosystem of PPB has been used for biochemical applications, including enzyme-mediated photo-catalysis or photo-bioelectrochemical devices. Indeed, it has been proved that PPB can be active both as electron donors (microbial fuel cells) as well as electron acceptors (microbial electrosynthesis), which is unusual in nature. This is due to their highly efficient electron allocation through their metabolism, which potentially yields one functional electron per electron assimilated, converting PPB into one of the most thermodynamically efficient organisms on earth.
Based on the above, the workshop is focused on two main topics:
- Biophysics of the light reactions of PPB: the capture of light, energy transfer and charge separation in the reaction centre and
- Biophysics and metabolic mechanisms of the electron-bacteria interaction in bioelectrochemical systems. Development of specific conductive or semiconductive materials.