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Endospore production allows using spray-drying as a possible formulation system of the biocontrol agent Bacillus subtilis CPA-8

Yánez-Mendizabal, V., Viñas, I., Usall, J., Cañamás, T., Teixidó, N.
Biotechnology letters 2012 v.34 no.4 pp. 729-735
Bacillus subtilis, Monilinia fructicola, Pantoea agglomerans, biological control, biological control agents, conidia, endospores, germination, heat, microorganisms, spray drying, viability
The role of endospore production by Bacillus subtilis CPA-8 on survival during spray-drying was investigated by comparison with a non-spore-forming biocontrol agent Pantoea agglomerans CPA-2. Endospore formation promoted heat resistance in CPA-8 depending on growth time (72 h cultures were more resistant than 24 h ones). The survival of CPA-8 and CPA-2 after spray-drying was determined after being grown in optimised media for 24 and 72 h. Spray-dried 72 h CPA-8 had the best survival (32%), while CPA-2 viability was less than 2%. CPA-8 survival directly related with its ability to produce endospores. Spray-dried CPA-8 reduced Monilinia fructicola conidia germination similarly to fresh cells, demonstrating that spray-drying did not adversely affect biocontrol efficacy. Endospore production thus improves CPA-8 resistance to spray-drying. These results can provide a reliable basis for optimising of the spray-drying formulation process for CPA-8 and other microorganisms.