18 Apr 2005 13:30
Unit:
Wageningen University
Location:
Aula (gebouw 362), Gen. Foulkesweg 1, Wageningen
Promotor:
prof.dr.ir. J. Tramper (Bioprocess Engineering)
Co Promotor:
dr.ir. A. Rinzema
Since over 2000 years man has cultivated fungi on grains, beans or other (by)products from agriculture or agro-industries, in order to produce tastier and healthier foods. Nowadays, cultivation on solid substrates (solid-state fermentation, SSF) is also used to produce industrial enzymes, drugs and biological plant protection agents. Wider application of SSF is hindered by a lack of knowledge about the design and control of the process. An important problem in SSF is the limited rate of oxygen supply to the fungal mats on the substrate surface. Using the fungus Aspergillus oryzae as an example, we have discovered that aerial mycelia – which fungi can only form in SSF – help the fungus to overcome this oxygen supply limitation, and thus grow faster and make more enzymes of interest to the food industry. We have also identified other factors related to substrate pre-treatment that have a large impact on product formation. These findings offer opportunities for improved SSF processes.
This work was performed as part of the WCFS project on Solid-State Food Fermentations.