Investigations of cephalosporin C production in an airlift tower loop reactor

Summary Cephalosporin C was produced by Cephalosporium acremonium in a 60 l airlift loop reactor on complex medium (with 30 kg/m³ peanut flour) in fed-batch operation. A final product concentration of 5 kg/m³ and a maximum productivity of 45 g/m³ h were attained. On-line analysis was used to determine ammonia, methionine, phosphate, reducing sugar and cephalosporin C by an autoanalyser, glucose by a flow injection analyser and cephalosporin C, penicillin N, deacetoxycephalosporin C, deacetylce-phalosporin C and methionine by HPLC. The volumetric productivity of the stirred tank reactor was higher than that of the airlift reactor because of differences in cell concentration. Specific productivities in relative to cell mass were similar in the two reactors. The substrate yield coefficient in the airlift reactor was twice that in the stirred tank reactor.Nomenclature E _o2 efficiency of oxygen transfer with regard to the specific power input - K _La volumetric mass transfer coefficient - OTR oxygen transfer rate - P power input - PR volumetric productivity of CPC - q _a volumetric aeration rate/broth volume (vvm) - SPR specific productivity with regard to RNA - V _L broth volume in reactor - z relative height of the aerated reactor