Farhat Qasim

• In recent years, solid-state fermentation [SFF] has gained the interest of the research community by showing remarkable developments in bioprocesses. It has emerged as a technology with the potential for producing microbial products such as pharmaceuticals, industrial enzymes, secondary metabolites, feed & food, and biofuels. Mucor racemosus CBS 381 was grown on optimized solid media (wheat bran) using the software, Design of Experiment (DoE). Based on laboratory-scale experiments the the SSF was scaled up by establishing a precisely controlled environment by utilizing Terrafors-IS Infors HT in-situ sterilizable rotating solid-state bioreactor. SSFs were introduced to predict the effect of shear forces caused by drum rotation on the overall biomass and enzyme production. Additionally, the aeration requirement and sensitivity of fungal growth and its effect on the final product were also investigated in combination with various moisture levels. Fermentations were performed with high and low moisture content i.e. 90% and 60% in combination with the flow rate of 1 and 2 L/min. Crude extract analysis via scale-up SSF with 60% moisture content and the airflow provided 1 L/min, exhibited ~570 U/mL milk-clotting activity with ~1600g biomass. However, the 2 L/min flow with 60% moisture content resulted in less biomass with reduced milk clotting activity. 90% moisture content with a 1 L /min Flow rate has resulted in enhanced biomass production i.e. ~1800 g and enzyme with the milk-clothing i.e. 558 U/mL. This study revealed that low moisture and low aeration levels lead to an increase in enzyme activity. Enzyme purification was accomplished via ion exchange chromatography using a DEAE Sepharose Fast Flow column. A threefold increase in the enzyme activity of the crude extract was observed. By using the enzyme, fresh cheese was manufactured on a pilot scale utilizing pasteurized cow milk. Various properties of the cheese were analysed.