A novel spray bioreactor for the proliferation of plant callus; Hyoscyamus niger and Arnebia pulchra.

Objective: Unlike plant cell suspension culture, the proliferation of callus in bioreactors has received inadequate attention. The magnificent potential of plant callus becomes more appreciated as the research unfolds and promises interesting applications including the production of valuable metabolites, therapeutic antibodies, bioactive extracts with regenerating effects, and the generation of genetically improved plants. Issues such as the lack of 3D-access of the cells to the nutrients, using an interfering gelling substance as the support matrix, and the changes in the medium formulation during the growth phase were discouraging factors for extending research on this topic. Considering the existing drawbacks, a novel open-flow spray bioreactor (OFSB) was configured to circumvent the associated problems with the solid cell culture and promote the applicability of plant callus culture via improving the feeding strategy.

Methods: Applying similar subculture conditions, the proliferation of Arnebia pulchra and Hyoscyamus niger calli as the examples of two important plant families (Boraginaceae and Solanaceae) was studied in the OFSB in comparison with similar calli that grew in Petri dishes and jars.

Results: A. pulchra and H. niger calli obtained the weight gains of (%87.3 and %106.7) in the Petri dishes, (%208.7 and %226) in the jars, and (%288.6 and %320.0) in OFSB, respectively, while no significant changes were observed in the productivity indices of the examined calli.

Conclusion: The simple design of OFSB bypasses most of the notorious problems associated with solid plant callus culture. OFSB technical features allow the bioreactor to be used for growth optimization of various types of plant calli in a cost-effective manner.