Bioproduction potential from industrial and municipal waste streams through open-culture biotechnology

Widespread municipal and industrial feedstocks rich in organics are potential feedstocks for allocating biogenic carbon into circular bioproducts through open-culture biotechnology. In this work, we estimate the production potential of selected biochemicals (methane, lactate, medium-chain carboxylates [MCC]) and biopolymers (extracellular polymeric substances [EPS]; namely flocculant EPS and alginate-like EPS [ALE], and polyhydroxyalkanoates [PHA]). Theoretical and practical carbon and chemical oxygen demand (COD) efficiencies are presented to estimate their bioproduction potential in Europe (EU-27) based on a meta-analysis, feedstock-bioproduct compatibility assessment and Monte Carlo simulations. Potentially compatible feedstocks added up to about 60 and 20 Mton/year of COD and carbon, respectively, and comprised municipal wastewater, food waste and industrial wastewaters from the food (dairy, beverages, yeast and sugar) and pulp and paper (pulp, cardboard) sectors. Methane, a highly reduced molecule (oxygen/carbon ratio = 0), is the bioproduct that can recover the most COD (∼36 Mton COD/year) and carbon (∼7 Mton carbon/year) from the feedstocks, whereas oxygen-rich lactate (O/C = 1) showed the highest mass flux potential (∼12 metric Mton/year). From the biopolymers, flocculant EPS had the highest bioproduction potential (∼11 Mton COD/year). The estimated potentials could supply a significant fraction of the global market demand for e.g., plastic applications from lactate and PHA; or European targets for e.g., biomethane or sustainable aviation fuels (SAF) from MCC. A supply potential of EPS-based products in excess of their market applications demand indicate that further market development may be required. This study illustrates the opportunities for future commercialization of open-culture bioproducts.