The engineered Methylococcus capsulatus Bath presents a promising approach for converting methane, a potent greenhouse gas, into valuable chemicals. High cell-density culture (HCDC) is necessary for high-titer growth-associated bioproducts, but it often requires time-consuming and labor-intensive optimization processes. In this study, we aimed to achieve efficient HCDC of M. capsulatus Bath by measuring the residual nutrient levels during bioreactor operations and analyzing the specific uptake of each medium component. By controlling the concentrations of nutrients, particularly calcium and phosphorus via intermittent feeding, we achieved a high cell density of 28.2 g DCW/L and a significantly elevated production of mevalonate at a concentration of 1.8 g/L from methane. Our findings demonstrate that the methanotroph HCDC approach presented herein offers a promising strategy for promoting sustainable development, with an exceptional g-scale production titer for value-added synthetic biochemicals.
Keywords: high cell-density culture; methane valorization; methanotrophs; mevalonate.