NOVEL IMMOBILIZED CELL REACTOR FOR MICROBIAL OXIDATION OF H2S

In a continuous fermentation, significant advantages may be gained by immobilization of microbial cells. Immobilization allows cells to be retained in the fermenter or to be readily recovered and recycled. A novel cell immobilization has been developed for the immobilization of autotrophic bacteria by coculture with floc-forming heterotrophic bacteria with growth of the latter limited by the availability of organic carbon. The result is an immobilization matrix which grows along with the immobilized autotroph. The chemoautotroph Thiobacillus denitrificans has been immobilized in macroscopic floc by coculture with floc-forming heterotrophs from an activated sludge treatment facility. Floc produced were subsequently used to remove H2S from a gas stream bubbled through a continuous culture with total biomass recycle. The ultimate biomass concentration was dependent upon the H2S feed rate and the H2S removal efficiency was influenced by the biomass concentration. © 1990.