Challenges in cellulolytic enzyme production by filamentous fungus Trichoderma reesei Rut C-30 on cellulosic materials

Poster (konferens), 2013

The industrial cellulase production is dominated by the filamentous fungus Trichoderma reesei. The switch of the carbon sources from lactose, traditionally used for industrial cellulase production, to lignocellulose, such as residual plant materials, could potentially reduce the cost of the enzyme production process. However, enzyme productivities are significantly lower on cellulose than on lactose. We studied the enzyme production by T. reesei strain Rut C-30 on model and industrial cellulosic substrates. Our aim was to understand how different raw materials influence the levels and profiles of the proteins produced. Enzyme production by T. reesei Rut C-30 was studied in submerged cultivations on commercial cellulose Avicel and industrial-like cellulosic substrates from softwood, which mainly consist of cellulose, but also contain residual hemicellulose, lignin and some inhibitors. These substrates were produced by alkaline pulping, used in pulp and paper industry. In order to evaluate hydrolysis and consumption of the substrates by fungal enzymes, the substrates were characterized by HPAEC-PAD and solid-state NMR. Lignin was analyzed by gravimetric method. Protein profile was examined by isobaric tag for relative and absolute quantification (iTRAQ). Inhibitors, soluble sugars and lignin degradation products did not have impact on the growth ability of T. reesei Rut C-30, but the fungal morphology was severely influenced during the growth on industrial-like substrates. Industrial-like substrates yielded less enzymes and enzyme adsorption may be one important factor influencing protein yields in the cultivations. Fungal growth on different substrates resulted in distinct protein profiles.