Wednesday, November 15, 2006
306-21

A Closed Bioreactor Design for Studies of Bacterial Carbon Dioxide Fixation.

R.P. Voroney and S. Mejia. University of Guelph, Guelph, ON n1g 2w1, Canada

 

Photosynthetic bacteria have a potential doubling rate that ranges from minutes to a few hours, depending on their biology and on chemical and physical factors in the environment in which the cells are growing.  Under natural conditions CO2 consumption rates by phytoplankton of 0.312 g CO2 g-1 cell mass h-1 have been recorded.  Based on this theoretical understanding, an experimental bioreactor was designed and constructed to measure the CO2 consumption activity of photosynthetic bacteria. The reactor was equipped with sensors to measure media pH and electrical conductivity and controlled CO2 gas intake.  It was also equipped with a gas sampling chamber containing sensors that measured humidity, pressure and CO2 gas exhausted from the reactors. These data were used to calculate CO2 fixation by the bacteria.  In total, six experiments were carried out, with incubation periods ranging from two days to seven days. This study measured photosynthetic rates for one purple non sulfur bacteria and one green non sulfur bacteria. This research measured CO2 consumption rates similar to those reported for growth under natural conditions. For Rodospeudomonas palustris, the CO2 uptake rates were from 0.543 g CO2 g-1 cell mass h-1 to 1.038 g CO2 g-1 cell mass h-1, and for Rodobacter capsulatus the CO2 uptake was 0.359 g CO2 g-1 cell mass h-1.                                     R. Paul Voroney, (519) 824-4120, pvoroney.@uoguelph.ca