Bioprocessing of environmentally significant gases and vapors with gas-phase bioreactors

Abstract

Fixed thin film, gas/vapor phase bioreactors were assessed relative to their potential for the bioprocessing of methane, trichloroethylene (TCE), and p-xylene. Methanotrophic bacteria were used to process the methane and TCE while a xylene resistant strain of Pseudomonas putida was used to process the p-xylene. Comparisons between the gas phase bioreactors and conventional shaken cultures and sparged liquid bioreactors showed that the gas phase bioreactors offer advantages over the other two systems for the degradation of methane in air. Rates of methane removal with the gas phase bioreactors were 2.1 and 1.6 fold greater than those exhibited by the shaken cultures and sparged liquid bioreactors, respectively. The gas phase bioreactors were shown to have application for the removal of TCE vapors from air with a removal rate of approximately 9 μg TCE d-1 bioreactor-1. Xylene vapors were also scrubbed from air using gas phase bioreactors. At a feed rate of 140 μg of xylene min-1, approximately 46% of the xylene was mineralized to carbon dioxide in a single pass through a bench scale gas phase bioreactor.