Assessing the performance of synthetic co-cultures during the conversion of methane into Poly(3-hydroxybutyrate)

Synthetic co-cultures can enhance pollutant bioconversion performance through synergistic effects among co-existing species. In this study, the potential of Methylocystis hirsuta and Methylocystis parvus to support poly(3-hydroxybutyrate) (PHB) production in co-cultivation with Rhodococcus opacus and Pseudomonas putida under a CH4:O2 atmosphere was assessed batchwise. The metabolic activation of almost all co-cultures studied was faster than that of single strain cultures, bringing higher methane and oxygen consumption rates. Higher PHB yields were achieved when coupling M. hirsuta with R. opacus (63 % w w−1) or with R. opacus and P. putida (64.4 % w w−1) compared to M. hirsuta alone (38.5 % w w−1). Interestingly, the combination of both R. opacus and P. putida with M. parvus reduced PHB accumulation to 42.2 % w w−1 compared to the content observed in M. parvus monocultures (62.2 % w w−1) and M parvus + R. opacus co-cultures (66.6 % w w−1).