Winda Soerjawinata

The main focus of my study is to find the optimum condition of the fermentation process for the production of protease inhibitor. The composition of the medium for the fermentation is varied as well as the spore inoculum for starting the fermentation. The goal is to find any trend from these variations and pick one best condition for the production of the protease inhibitor.

I normally start the bioreactor fermentation on Friday. The fungi need up to 48 h to go through their lag phase until they form pellets. Therefore, I can enjoy the weekend without the need to take samples. As soon as the pellets are formed, I will take samples every 8 hour a day. After the fermentation is finished, the fungal biomass will be harvested. The extraction process will take place until the extract of protease inhibitor is obtained. In order to prove the production of protease inhibitor in every fermentation, an assay is performed by reacting the protease inhibitor against rhodesain enzyme. If protease inhibitor is produced, the rhodesain will be inhibited and no product can be detected from the reaction; on the other hand, if the inhibitor activity is low, the rhodesain can still react with the substrate and produce a fluorescence substance as product. The production of protease inhibitor is presumably influenced by the fungal pellet morphology. Thus, the pellet morphology is also investigated in my study. The pellets are in Paraffin embedded and then 20 µm thin-sliced using Microtome. The internal structure of the pellets is observed using microscope.

The growth curve of the fungi in every fermentation, metabolic activity depicted on the pH-course during the fermentation, analysis of the pellet morphology as well as protease inhibitor activity are compared between the fermentations.