Beschreibung
This thesis aims at the design of a continuous and robust bioprocess to produce nylon monomers from cyclohexane. Cyclohexane is a challenging substrate for biotechnological applications due to its physicochemical properties such as low water solubility, high volatility, and toxicity. These properties need to be considered for the choice of the best biocatalyst format as well as the most suitable reactor configuration. To establish a continuous process, stable and robust biocatalysts such as whole-cells or biofilms are required. For this thesis, P. taiwanensis VLB120 was chosen as a model organism due to its solvent resistance and ability to form biofilms. Biofilms are highly stable against toxic compounds and facilitate continuous biocatalysis by natural self-immobilization. However, the matrix they are embedded within limits the diffusion of essential nutrients, including oxygen. Therefore, different reactor configurations were studied to identify bottlenecks for biofilm growth and efficient biocatalysis. A suitable cyclohexane feeding strategy was investigated for suspended cultures with respect to efficient mass transfer and concomitantly reducing toxification. The performance, product formation, and stability of the suspended whole-cell biocatalysts were compared to biofilms to estimate the future potential of both biocatalysts formats for biocatalytic adipic acid production.
