Bacillus subtilis spores are a point of interest for many biotechnological applications, due to their resistance towards different environmental stresses. Their resistance comes from the multi-layered spore-coat, which also consists of the CotA protein that exhibits laccase activity. Laccases are capable of oxidizing different substrates, among which 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) is commonly used as a standard to determine their activity. The use of spores as biocatalysts in microflow systems has many advantages in the development of miniaturized biosensors or flow systems for degradation of phenolic substances. In the scope of this master’s thesis, the influence of spore thawing procedure on laccase activity was initially studied. Moreover, a mathematical model of ABTS oxidation in a microbioreactor with immobilized B. subtilis spores was developed, which can be used to describe and predict process behavior. Kinetic parameters were determined by fitting the derived mathematical model on experimental data obtained from a microflow system. With variation of process variables, their influence on the process yield was investigated. In the end, we tried to mechanistically describe the loss of productivity with a non-stationary model due to the process of spore flushing from the reactor.
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