Analysis of suspended and biofilm atrazine degrading cells

BIOT 237

Nicole Kim Biglione, biglione@engineering.uiowa.edu, Chemical and Biochemical Engineering, The University of Iowa, 4133 Seamans Center, Iowa City, IA 52242, Victor GJ. Rodgers, victor.rodgers@ucr.edu, Department of Bioengineering, University of California Riverside, Bourns Hall A237, Riverside, CA 92521, and Tonya L. Peeples, tonya-peeples@uiowa.edu, Department of Chemical and Biochemical Engineering, The University of Iowa, Iowa City, IA 52242.
Increasing public concern over the safety of the s-triazine herbicide atrazine is fueling demands for methods to remove atrazine from water. In this research the ability of microbes in suspended and biofilm cultures to degrade atrazine is evaluated. Monod kinetic parameters, ”max and Ks, of Pseudomonas sp. ADP (P. ADP) in suspension were determined to be 0.14(+/-0.01) h-1 and 1.86(+/-1.80) mg/L at 200 rpm and 27șC and 0.22(+/-0.01) h-1 and 6.30(+/-1.44) mg/L at 200 rpm and 37șC, respectively. Preliminary studies showed that P. ADP forms a biofilm. This work studies the relationship of this biofilm to atrazine consumption.

A spherical biofilm device was designed to allow for ease in modeling and experimental analysis of bioconversion and mass transfer. The mass transfer coefficient in this reactor was determined to 0.40 cm/sec at impeller speeds higher than 55 rpm. COMSOL 3.2 was used to model cell growth and atrazine consumption the biofilm reactor.

The main goal of this research is to determine the influence of suspended and biofilm cell populations on atrazine degradation. The degradation rate of atrazine and the cell growth rate in the suspended and biofilm cells will be presented. The rate-limiting step in the metabolic pathway as well as the transport limitations in each case will be discussed. Parameters developed from this research will be applied in the design of appropriate bioreactors for the application in industrial and environmental settings.

 

Poster Session
5:30 PM-7:30 PM, Wednesday, August 22, 2007 BCEC -- Exhibit Hall - B2, Poster

Division of Biochemical Technology

The 234th ACS National Meeting, Boston, MA, August 19-23, 2007