Poster Presentation 1B-51

Optimizing Medium Nitrogen Content for Cellulase Production

by Trichoderma reesei

Nóra Szijártó,¹ Zsolt Szengyel,¹ Gunnar Lidén² and Kati Réczey¹*

¹Department of Agricultural Chemical Technology

Budapest University of Technology and Economics

Szent Gellért tér 4

H-1521, Budapest, Hungary

Phone: +36 1 463 28 43

Fax: +36 1 463 25 98

E-mail: kati_reczey@mkt.bme.hu

²Department of Chemical Engineering

Lund University, P.O. Box 124, SE-221 00, Lund, Sweden

Nitrogen is quantitatively the second most important medium component for cell growth and is as such a determining factor for obtainable cell yields. In enzyme production, nitrogen is a key component also for the excreted product, since an average protein contains more than 15wt% of nitrogen.

In the current study, the effects of the medium nitrogen content on obtained enzyme activity were studied. In addition, potential long-term effects of the inoculum cultivation were tested by comparing inoculums grown on glucose and Solka floc.

Shake flask cultures were set up using modified Mandels medium with different initial C/N ratio at a desired C content and also with different initial C content at a desired C/N ratio. Parallel studies were completed using glucose and Solka floc grown inoculum cultivations.

The results showed that the obtained final enzyme activities did not increase significantly above a nitrogen content of 0.4 g/l when 10 g/l carbon source was initially applied. This nitrogen level was slightly lower than estimated stoichiometric needs for biomass synthesis. The inoculum cultivation was found to have a small but significant effect on the final enzyme activity. A slightly higher (close to 10%) activity was obtained in case of inoculum cultures grown on Solka floc compared to that achieved with glucose grown inoculum cultures.