SELECTIVE USE OF MICROORGANISMS IN ANAEROBIC TREATMENT PROCESSES BY APPLICATION OF IMMOBILIZATION

The cell immobilization technique using polyvinyl alcohol and boric ac id was applied to the anaerobic process. Immobilized cells of Clostrid ium butyricum were used to enhance butyrate production in a continuous reactor under a mixed culture condition. There was a tendency that mo re butyrate was produced in the immobilized cell system than in the no n-immobilized cell system at (1) a dilution rate lower than 0.14 h(-1) at pH 6 and (2) a pH higher than 5.5 with a dilution rate of 0.036 h( -1). The enrichment culture of the propionate-utilizing consortium was immobilized and used in a mixed culture condition with suspended biom ass which could convert glucose to methane. Batch experiments using th is mixture of biomass and those using non-immobilized cells alone were carried out. Methane production from acetate, propionate or glucose p roceeded much more rapidly, and accumulation of propionate during gluc ose degradation was much shorter when the immobilized cells were used.