Screening of freeze-dried protective agents for the formulation of biocontrol strains, Bacillus cereus AR156, Burkholderia vietnamiensis B418 and Pantoea agglomerans 2Re40

Abstract

Aims: The effects of different freeze‐drying protective agents on the viabilities of biocontrol strains Bacillus cereus AR156, Burkholderia vietnamiensis B418 and Pantoea agglomerans 2Re40 were investigated. Method and Results: Several concentrations of protective and rehydration media were tested to improve the survival of biocontrol agents after freeze‐drying. The subsequent survival rates during storage and rehydration media of freeze‐dried biocontrol strains were also examined. Conclusions: The results indicated that cellobiose (5%) and d‐galactose (5%) gave maximum viability of strains Bu. vietnamiensis B418 and P. agglomerans 2Re40 (98 and 54·3% respectively) while the perfect one (100%) of strain B. cereus AR156 was obtained with sucrose (5%) during freeze‐drying, and the highest survival of the three strains was reached when they were rehydrated with 10% nonfat skim milk. In the following storage, the survival rates showed that B. cereus AR156 could still reach 50% after 12 months. Significance and Impact of the study: This study showed that freeze‐drying could be used to stabilize cells of these three biocontrol strains. Further studies should focus on the scale‐up possibilities and formulation development.

Formulation of the biocontrol agent Bacillus amyloliquefaciens CPA-8 using different approaches: liquid, freeze-drying and fluid-bed spray-drying

“…In contrast, CPA-8 cells amended with sucrose or sucrose plus SM provided higher degree of cell protection during drying. Other authors have reported the beneficial role of sugars (Costa et al, 2000;Navarta et al, 2011;Zhan et al, 2011), which replace structural water in membrane after rehydration and prevent unfolding and aggregation of proteins (Champagne et al, 1991). The results obtained when MgSO4 was added to CPA-8 cells prior FD -alone or in mixture with SM-are in agreement with the work conducted by Yánez-Mendizábal et al (2012b).…”

Optimization of a protective medium for freeze-dried Pichia membranifaciens and application of this biocontrol agent on citrus fruit

“…Results showed that sucrose was the most effective protectant among the saccharides, which was consistent with the findings of Zhan et al . (); sorbitol was a worse protectant than the other saccharides, which was in accordance with the observations of Abadias et al . ().…”

Survival and beneficial properties of lactic acid bacteria from raniculture subjected to freeze-drying and storage

“…; Zhan et al . ). Many factors have been reported to affect the freeze‐drying survival of LAB and their subsequent storage such as initial cell concentration, growth media, freezing rate and temperature and storage temperatures (Carvalho et al .…”