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Title: The production and kinetics of Trichoderma reesei cellulase
Author: Herrera Zeppelin, A. L.
Awarding Body: University College of Swansea
Current Institution: Swansea University
Date of Award: 1983
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Attempting to enhance cellulase yields obtained from the fungus Trichoderma reesei (9414), the fungus was grown in a tall and narrow 50 litres air lift fermenter at low aeration rates (3.9 to 6.0 1/min). A characterization of the performance of the fermenter showed that the chosen substrate of growth (solka floca SW40) could be maintained in suspension. In order to minimize turbulence and shear, a concentric, cylindrical, reverse flow pattern fermenter was built. Activities obtained were slightly higher than those obtained in a stirred tank and similar to those obtained in shake flask cultures. In order to further the knowledge of the mode of action of cellulases to help the design of appropriate fermenters, an effort was made to model, in a mechanistic manner, the mode of action of the enzyme. The enzyme mixture was assumed to be composed of an Endo and an Exo acting cellulases and a cellobiase, the three enzymes were assumed to act simultaneously and synergistically. Two different models were developed which offer different advantages. The molecules model assumes the reactions to occur at the monomer (cellobiose) in a polymer (cellulose) and the bonds model assumes reactions to take place at each beta 1,4 linkage between the monomers. Several simulations were run to illustrate the different properties of the models. The bonds models offers an advantage in being easily modified to account for different substrates whilst the molecules model was developed assuming a linear arrangement of cellobioses. The molecules model can, however, account for any required number of oligosaccharides. The models were used to perform a number of parameter estimation experiments. From a model discrimination point of view, both models performed similarly but the bonds model parameters were more consistent. The data used for the parameter estimation experiments was limited and the deficiencies of the current analytical methods used for data collection were discussed, possible improvements were suggested with a significant, if limited, amount of evidence to prove their strength.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available