Carrousel-type photobioreactors at the URJC wastewater treatment plant. Courtesy: URJC
Purple phototrophic bacteria absorb infrared energy through their photosystem, which is composed of carotenoids and bacteriochlorophylls and can be used to extract valuable products, such as biofuels like biohydrogen, bioplastics like PHA and even single-cell proteins, from waste sources.
According to an article on BIOPLASTICNEWS.com the end product obtained depends on the environmental conditions of the bacteria including intensity of IR light, temperature and nutrient concentration.
Wastes rich in nitrogen help the bacteria grow biomass with a high protein content that can be used as an animal food additive. In organic waste lacking nutrients, the bacteria can produce large amounts of PHA (up to 70-90% w/w).
