PHA production and evaluation of target applications
Work Package 4, led by UNIPD and with the collaboration of EuroNewPack, BTS Biogas and the DTU, focuses on the bioconversion of CO2 to PHA. In particular, two microorganisms with the ability to produce PHA are investigated in this task: the bacterium Cupriavidus necator and the cyanobacterial strain Synechocystis sp. B12. The source of CO2 tested for bioconversion is biogas, which was provided by BTS Biogas. After a period of monitoring the characteristics of biogas plants and the composition of the product, experiments have been conducted to test the capability of the two microorganisms to capture CO2 from the biogas and use it for growth and PHA production.
Left: 1L Fed-batch fermentation set-up using C. necator DSM 545. Center: recovered PHA after standard chloroform-methanol extraction protocol.
Right: photobioreactors for growth of Synechocystis sp. B12.
Preliminary results show that for both microorganisms, CO2 uptake is not hindered by the presence of up to 50% methane in the headspace, a promising observation that demonstrates feasibility of the bioconversion and paves the way for upscaling the process. While preparations are underway to bring cultures to pilot scale, an array of conditions triggering PHA accumulation are being tested, including limitation of oxygen and ammonium. The coming months will also involve experiments on PHA to test their applicability for the production of plasticware.