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


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.


CONCLUSIONS
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.
Department of Plant Pathology, Engineering Center of Bioresource Pesticide in Jiangsu Province, Key Laboratory of Monitoring and Management of Crop Diseases and Pest Insects, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, China.
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Y
Zhan
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Xu
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Yang
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HT
Yang
H-X
HX
Liu
Y-P
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Wang
J-H
JH
Guo
D000818:Animals; D001409:Bacillus cereus / Q000187:drug effects / Q000502:physiology*; D019117:Burkholderia / Q000187:drug effects / Q000502:physiology*; D002475:Cellobiose / Q000494:pharmacology; D003451:Cryoprotective Agents / Q000494:pharmacology*; D005690:Galactose / Q000494:pharmacology; D018551:Solanum lycopersicum; D050296:Microbial Viability; D008892:Milk; D020636:Pantoea / Q000187:drug effects / Q000502:physiology*; D010572:Pest Control, Biological; D010935:Plant Diseases / Q000517:prevention & control; D013395:Sucrose / Q000494:pharmacology
D003451:Cryoprotective Agents; D002475:Cellobiose; D013395:Sucrose; D005690:Galactose