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Application 1025

Soft alginate beads used in a rotating bed reactor

Stirred vessels tend to damage soft heterogeneous catalysts, like enzymes immobilized in agarose or alginate beads, with activity loss and tedious workup as consequence. In a fixed bed reactor, these materials are easily compressed by the pressure gradient, leading to a loss of flow rate. Overcoming these challenges opens up the possibility to use biocatalysis as a tool for greener processes and more sustainable manufacturing.

“Compared to chemical processes, whole cell biocatalysts offer several advantages including high selectivity, catalytic efficiency, milder operational conditions and low impact on the environment” - Anteneh, Y. S., Franco, C. M. M., Whole Cell Actinobacteria as Biocatalysts

The use of a SpinChem® rotating bed reactor (RBR) allows easy collection, washing and recycling of alginate beads and other soft particles. It is possible to immediately and without filtration continue with the next process step, e.g., charging the vessel with reaction substrate. This reduces the number of unit operations and facilitates bead recycling. The alginate beads are protected against any mechanical damage, extending the lifetime of the beads. The severe compression of the beads that is expected in a fixed bed reactor is avoided, which improves the flow and mass-transfer rates.

This video shows the formation of alginate beads under conditions mimicking whole cell encapsulation. The method of loading the rotating bed reactor by drawing the solid-phase from the bulk liquid is further demonstrated in these applications:

Biocatalytic applications are simplified in the rotating bed reactor, whether it involves encapsulated whole cells or enzymes immobilized on commercially available supports. Reach out to us for a discussion about your application.

Further reading:

Industries Pharmaceutical

Topics Biocatalysis, Reactor Engineering, Support, Downstream Processing, Process Development

Products SpinChem® RBR S2, SpinChem® Vessel V2

Details

Conditions: A SpinChem® S2 RBR with only outer filter was rotated at 50 rpm in an aqueous calcium chloride solution (200 mL, 50 mM) in a SpinChem® V2 flower-baffled reaction vessel, while an alginate solution (3.6%) mixed 1:1 with a simulated cell suspension consisting of 50 mM phosphate-buffered saline (PBS) coloured with methylene blue (100 mg/L), was added dropwise through a fine-tipped needle. The alginate beads formed instantaneously and were slowly drawn into the RBR where they were solidified for 10 min, after which the rotational speed was increased to 300 rpm and the vessel was drained from solution, washed with fresh aqueous calcium chloride solution and drained again. Pure water was added to mimic a substrate solution and finally the RBR was stopped and emptied from alginate beads which was observed to have an intact round morphology.