Biomass reduction and mineralization increase due to the ciliate Terahymena pyriformis grazing on the bacterium Pseudomonas fluorescens
Ratsak, C.H., Kooi, B.W. and Verseveld, H. W. van 1994.
Biomass reduction and mineralization increase due to the ciliate
Terahymena pyriformis grazing on the bacterium Pseudomonas
fluorescens.
Wat. Sci. Tech. 29: 119 - 128
Abstract
The currently high sludge production and increasing processing costs
call for waste-water treatment plants with high purification
efficiency and low biomass production. We studied the latter issue
through two-stage chemostat cascades to assess the overall biomass
reduction due to ciliate grazing. The bacteria were cultured in the
first chemostat whereas the ciliates, grazing on the bacteria from the
first chemostat, were cultured in the second chemostat. Mathematical
modelling was used to describe the bacteria/ciliate dynamics and some
of the growth parameters were fitted. In the second chemostat 22-44%
of the carbon originating from the first chemostat was mineralized to
CO2. An extra biomass reduction of 12-43% was possible due
to grazing by the ciliates. At lower growth rates of the ciliates the
extra biomass reduction was higher than at high growth rates. This
finding is auspicious, suggesting that predator organisms indeed can
reduce sludge production.