Applied Biochemistry and Biotechnology
Vol. 121–124, 2005
Copyright © 2005 by Humana Press Inc.
All rights of any nature whatsoever reserved.
Performance of an Internal-Loop
Airlift Bioreactor for Treatment
of Hexane-Contaminated Air
J. S. O
Departamento de Engenharia Bioquímica, Escola de Química, Centro
de Tecnologia, Universidade Federal do Rio de Janeiro, Ilha do Fundão,
Rio de Janeiro, RJ, Brazil, CEP 21949-900, E-mail: email@example.com
Hexane is a toxic volatile organic compound that is quite abundant in
gas emissions from chemical industries and printing press and painting
centers, and it is necessary to treat these airstreams before they discharge
into the atmosphere. This article presents a treatment for hexane-contam-
inated air in steady-state conditions using an internal-loop airlift bioreac-
tor inoculated with a Pseudomonas aeruginosa strain. Bioprocesses were
conducted at 20-mL/min, a load of 1.26 g/m
, and a temperature
of 28°C. The results of hexane removal efficiencies were presented as a
function of the inoculum size (approx 0.07 and 0.2 g/L) and cell reuse.
Bioprocess monitoring comprises quantification of the biomass, the surface
tension of the medium, and the hexane concentration in the fermentation
medium as well as in the inlet and outlet airstreams. The steady-state
results suggest that the variation in inoculum size from 0.07 to 0.2 g/L pro-
motes hexane abatement from the influent from 65 to 85%, respectively.
Total hydrocarbon removal from the waste gas was achieved during exper-
iments conducted using reused cells at an initial microbial concentration of
Index Entries: Air treatment; hydrocarbons; hexane biodegradation; airlift
bioreactor; Pseudomonas aeruginosa.
The inappropriate release of gaseous effluents into the atmosphere
promotes air contamination. The understanding of this phenomenon is
complicated by the high reactivity and hydrodynamic complexity of the
atmosphere, which makes it difficult to ascertain the short- and medium-
term effects of the discharges on human health. On other hand, it is
estimated that in the United States alone 1,000,000 kg of chemical sub-
stances is released annually into the atmosphere, and US$1,200,000 is
spent annually on the treatment of these effluents
*Author to whom all correspondence and reprint requests should be addressed.
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