The biotechnological development of purple phototrophic bacteria (PPB) focuses on resource recovery from waste sources, contributing to a circular bioeconomy. The technology is being scaled-up. However, technological implementation faces several challenges, as:

Knowledge transfer from pure to mixed cultures

Obtaining fundamental knowledge on nutrients uptake pathways

Developing mechanistic models

Steering cultures to selective and stable communities

Defining the targeted waste streams

Optimizing culture conditions based on light transfer

Optimizing downstream processing to extract products

Developing techno-economic, social and environmental life cycle assessments.

A holistic and multidisciplinary approach is required to overcome these bottlenecks. The combined efforts of basic and applied scientists and technologists from the industrial sector improve this emerging technology’s competitiveness in the EU, ultimately leading to technology deployment and product commercialization.

PURPLEGAIN aims to create a European network to share information, facilitating technology and knowledge transfer between the academic and industrial sectors, related to PPB applications for resource recovery from organic waste sources. Resource recovery includes wastewater or organic waste, open or closed environments, in single or chain processes. The network associates fundamental-focused and applied-research groups, improving lab-scale technology optimization through mechanistic modeling. It benefits the technology transfer from applied-research groups to industry, considerably improving process design.

PURPLEGAIN also aims to create a database for techno-economic, social and environmental impacts studies, which facilitates the marketability of both the PPB-based technologies and the products to extract. Some focused products are polyhydroxyalkanoates, single-cell proteins, biomass for energy, biomass as fertilizer, biohydrogen, carotenoids, terpenoids, organic acids, coenzyme Q10, and 5-aminolevulinic acid.