Spatiotemporal wax ester production dynamics in fixed bed reactors from Marinobacter atlanticus biofilms

Continuous synthesis of molecules via microbial biofilms is an advantageous approach for chemical production. To effectively apply this technology, we must first understand the spatiotemporal dynamics of production within a microbial biofilms. Here, we investigated wax ester accumulation in Marinobacter atlanticus biofilms along the length of a fixed-bed reactor over eleven days under different conditions. Biofilm protein quantification indicated that biofilm biomass increased during the first seven days of operation and was consistently highest in the reactor sections closest to the inlet across all time points. While biomass increased over time, total wax ester concentrations were widely variable (range from 12 to 116 mg/L), with average titer of 32 ± 27 mg/L and median titer of 19 mg/L. Approximately 66% of reactors produced wax ester titers between 10 and 30 mg/L, whereas 33% exceeded 35 mg/L. Unexpectedly, wax ester concentration was similar for all incubation times tested and sampling location in the fixed bed reactor. Further, imposing alternating conditions of high and low nitrogen availability had an insignificant effect on wax ester production in the biofilms. Wax esters in all samples had carbon chain lengths between C28 and C34. Overall, these findings demonstrate that wax ester production in Marinobacter atlanticus biofilms is dynamic and complex, and further optimization is required to support continuous wax ester production in biofilm-based biomanufacturing processes.