Enhanced glucan formation of filamentous fungi by effective mixing,oxygen limitation and fed-batch processing

Summary Glucan formation ofSchizophyllum commune andSclerotium glucanicum were investigated. Process data obtained during batch cultivation are presented. Glucan release can be improved by oxygen limitation. Thus, growth and glucan release are influenced by oxygen in opposite ways. Possible pathways of this oxygen-dependent regulation are discussed. A draft-tube/propeller system, rushtonturbine-, fan- and helicon-ribbon-impeller as well as a fundaspi and intermig agitator were tested. The 4-bladed fan impeller withd^*=0.64 yielded the best results, since effective bulk mixing is much more important than bubble break up (micromixing) with regard to this system. Fed-batch cultivation always resulted in higher rates of glucan formation than the batch process.