(751e) Effectiveness of Shear Protective Additives in Enzyme Production by Pelleted Phanerochaete Chrysosporium

Ligninolytic enzymes including lignin peroxidase, manganese peroxidase, and laccase play an important role in biodegradation and bioleaching. Phanerochaete chrysosporium is one of the well studied basidiomycetes to produce these three enzymes. The production of these enzymes is often conducted with solid state fermentation system as the strain's performance is compromised by shear stress caused by agitation and gas sparging. Limitations with solid state fermentation are relatively low efficiency and productivity, the difficulty for scaling up, and production inconsistency. In addition, P. chrysosporium needs oxygen to produce peroxidase. It is also very difficult to supply adequate oxygen to the interior of solid medium, leading to another serious limitation to enzyme production which has been significantly improved using pelletized P. chrysosporium culture in our previous studies. In this study, several shear protective additives including Pluronic F-68, BSA, Tween 80 and PEG8000 were compared for MnP production by pelleted P. chrysosporium. The results have shown that these additives increased the enzyme production significantly except BSA. After the optimization of concentration, Pluronic F-68 improved the productivity and enzyme level by 180% in 125mL flask. Moreover, the production in 5L stirred tank was achieved successfully at the agitation speed 300rpm. Additionally, some protective mechanisms were investigated in the study.