Abstract
A simulation test method (called TOC-HANDAI) was modified to examine the effect of microorganisms cell order regulation for biodegradation of surfactants.
Microorganisms cell order in the suspension used as an inoculum was made in the same order (103, 104, 105) by controlling the volume of river water for filtrate in every season.
Each eight surfactants and commercial detergents were tested for 14 days with shaking at 25°C in the dark. Samples were drawn periodically and biodegradation was determined by measuring the remaining TOC.
Biodegradation rate of most surfactant using 103 cell order inoculum was very different from using 104 and 105 orders during 14 days, though the results which were obtained with the other order inoculum corresponded well. Using the low cell order inoculum, biodegradability of the same surfactant showed wide fluctuation in every season, but using higher cell orders (104, 105) inoculum always showed stable results.
These results suggest that the regulation of microorganisms cell order is useful method which can stabilize the degradation rate and decrease the fluctuation on the simulation test.
