Biofilm dynamics characterization using a novel DO-MEA sensor: mass transport and biokinetics

Abstract

Biodegradation process modeling is an essential tool for the optimization of biotechnologies related to gaseous pollutants treatment. In these technologies, the predominant role of biofilm, particularly under conditions of no mass transfer limitations, results in a need to determine what processes are occurring within the same. By measuring the interior of the biofilms, an increased knowledge of mass transport and biodegradation processes may be attained. This information is useful in order to develop more reliable models that take biofilm heterogeneity into account. In this study, a new methodology, based on a novel dissolved oxygen (DO) and mass transport microelectronic array (MEA) sensor, is presented in order to characterize a biofilm. Utilizing the MEA sensor, designed to obtain DO and diffusivity profiles with a single measurement, it was possible to obtain distributions of oxygen diffusivity and biokinetic parameters along a biofilm grown in a flat plate bioreactor (FPB). The results obtained for oxygen diffusivity, estimated from oxygenation profiles and direct measurements, revealed that changes in its distribution were reduced when increasing the liquid flow rate. It was also possible to observe the effect of biofilm heterogeneity through biokinetic parameters, estimated using the DO profiles. Biokinetic parameters, including maximum specific growth rate, the Monod half-saturation coefficient of oxygen and the maintenance coefficient for oxygen which showed a marked variation across the biofilm, suggest that a tool that considers the heterogeneity of biofilms is essential for the optimization of biotechnologies.2

Online oxygen monitoring using integrated inkjet-printed sensors in a liver-on-a-chip system

“…The theoretical model describing DO distribution was based on the mass balance along the ExoLiver reactor. Development of the mathematical model was based on the assumptions underlying consolidate models, 61 as follows:…”

Application of a novel respirometric methodology to characterize mass transfer and activity of H2S-oxidizing biofilms in biotrickling filter beds

“…The common practice is to calculate elemental sulfur production based on mass balances between the sulfide removed and the sulfate produced [32,[42][43] , which cannot be measured either. Developing monitoring tools and methods for obtaining additional data from biofilms is warranted for improving our modeling approach and to gain knowledge and robustness in the models proposed [44]. Such data together with a classical sensitivity analysis [45] would also contribute to reduce uncertainty of model parameters estimation.…”

CFD modeling of a fixed-bed biofilm reactor coupling hydrodynamics and biokinetics

“…The reactor included two reservoirs, located at the inlet and the outlet of the flat plate, which were 2 cm long, 3.5 cm wide and 2.8 cm tall. The FPB was inoculated and operated as described in [25]. During DO profiles recording, operating conditions were set up reproducing those typical of a conventional biotrickling filter (liquid phase velocity and residence time were adjusted to approximately 1 m h −1 and 12 hours respectively by using a peristaltic pump to recirculate the phase through the FPB).…”

“…(2) The biofilm is covered by a liquid film of constant thickness. (3) Biomass is considered heterogeneous, since it has been observed in previous studies for this type of bioreactors [25]. Therefore, a biomass density gradient has been defined along the biofilm.…”

“…DO microsensors measurements were performed in order to characterize the biological activity within the biofilm under both endogenous and substrate consumption conditions and to study biofilm heterogeneity, as it has been reported in previous works [25]. Twenty-four oxygen concentration profiles (twelve during endogenous conditions and twelve substrate consumption conditions) were measured at six different regions along the flat plate bioreactor (FPB).…”