Aims: To enhance the productivity of Cephalosporin C (CPC) by cultivation of Cephalosporium acremonium M25 using a mixture of inocula.
Methods and results: Inoculum age was classified into three stages (early, intermediate and late) by image analysis. A mixture of inocula, according to the inoculum ages, was used for efficient production of CPC in the main culture. The most effective mixing ratio of inocula for CPC production in shake flasks was a 3 : 7 volume ratio of early- and late-stage inocula. This was also the case in a 1.5 l stirred-tank reactor. CPC productivity was enhanced by about 32% and 34% when using an inoculum mixture in the shake flask and 1.5 l stirred-tank reactor, respectively.
Conclusion: The morphological characteristics of C. acremonium M25 in the seed culture were quite different according to inoculum age. The compromise of different ages of inoculum showed better production of CPC.
Significance and impact of the study: The productivity of CPC was enhanced considerably when using mixed inocula. The results of this study can be applied to fungal cultures for efficient production of various metabolites.