Among different waste streams, agri-food biowaste has become increasingly more relevant due to the significant environmental consequences resulting from improper treatment and disposal. Resource recovery from such biowaste streams, turning waste into valuable resources (such as bioplastics, biofuels, single cell proteins and biostimulants), can represent a promising solution to reduce environmental impacts related to waste disposal and natural resource consumption.
The innovative application of purple phototrophic bacteria (PPB) for resource recovery from various biowaste streams, particularly as microbial mixed culture grown via photoheterotrophic metabolism, is drawing considerable attention. In fact, by using solar light as energy source, PPB can simultaneously assimilate carbon and nutrients at high efficiencies, while maximizing the recovery of resources.
As the use of PPB for high-rate biowaste stream treatment and resource recovery is still in its early stages, the primary goals of this project are (i) to improve the understanding of mechanisms of PPB growth on agri-food biowaste through a combined experimental and modelling approach, and (ii) to investigate the integration of resource recovery by PPB in existing plant layouts, in the view of enhancing process performance and promoting sustainable scale-up. To this end, lab-scale reactors for PPB cultivation will be designed and operated to identify the optimal operating conditions. Moreover, resource recovery will be evaluated, possibly looking at biopolymer accumulation in biomass and protein production. Finally, based on the experimental and modelling results, a pilot-scale optimized photobioreactor will be designed and developed.

Reference teacher: Dr. Andrea Turolla – andrea.turolla@polimi.it