Optimisation of cellulose conversion into fungal cell mass

Chaetomium cellulolyticum was cultivated on Avicel and/or stream-and NH3-pre-treated straw in a 20 litre stirred tank reactor with batch and/or fed-batch operation. The influence of the substrate concentration, the impeller speed and the fed-batch operation on cell productivity was investigated. Steam-pretreated straw can be better utilised by the fungus than NH3-pretreated straw. The optimal conditions at which maximum cell productivity and/or maximum cell mass concentration can be attained were evaluated for stream-pretreated straw. At the beginning of the growth phase the oxygen consumption rate reaches a significant maximum. At this point the enzyme activity begins to increase. The investigations with Avicel indicate that the cell productivity could be significantly increased by fed-batch operation. A microprocessor-controlled fed batch process controlled by alkaline consumption is recommended.