Estimating the cellular maintenance coefficient and its use in the design of two-phase partitioning bioscrubbers

Abstract

One of the key roles of an organic solvent has emerged to be the enhancement of oxygen transfer in two-phase partitioning bioscrubbers (TPPBs). In order to determine an optimum organic fraction for a given VOCs loading, the oxygen demand of the total cell mass must be estimated, which depends upon the magnitude of the cellular maintenance coefficient. We have estimated the dynamics of the maintenance coefficient for benzene degradation by Achromobacter xylosoxidans Y234 in a TPPB and found that the maintenance coefficient generally decreased as cells accumulated in the TPPB but converged to a specific value of 1.750 x 10(-2) h(-1) at biological steady state. Due to its important influence on all of the essential design parameters of the TPPB system, including optimum organic fraction, aeration rate and agitation speed, the maintenance coefficient should be considered as a key biological determinant for microorganism selection, as well as in overall TPPB design.

A strategic approach for the design and operation of two‐phase partitioning bioscrubbers for the treatment of volatile organic compounds

“…Although the maintenance coefficient is variable during TPPB operation, 20 it converges to a specific value at biological steady state where there is no observed net increase in cell mass as most of the substrate supplied is used in support of the maintenance requirements of the cells with negligible changes to the aqueous and organic substrate concentrations. 7 Under this condition, the following equation can be used to estimate the maintenance coefficient.…”