Selection and optimization of Bacillus atrophaeus inoculum medium and its effect on spore yield and thermal resistance.
Bacillus atrophaeus's spores are used as biological indicators to monitor sterilization processes and as a Bacillus anthracis surrogate in the development and validation of biosafety methods. The regular use of biological indicators to evaluate the efficiency of sterilization processes is a legal requirement for health services. However, its high cost hinders its widespread use. Aiming at developing a cost-effective inoculum medium, soybean molasses and nutrient-supplemented vinasse were evaluated for their effectiveness in solid-state fermentation (SSF). In biomass production, the results demonstrated that all tested compositions favor growth by providing the nutritional demands of the microorganism. Optimum casein peptone and soybean molasses concentration (1.0%, 2.5%, or 4.0%) was determined by a 2((2-0)) factorial experimental design. The results have showed a positive influence of peptone on biomass production. In order to define peptone final concentration (4.0% or 6.0%), a 2(2) factorial experimental design was used. An optimized medium containing 4.0% soybean molasses and 4.0% casein peptone was similar in performance to a synthetic control medium (tryptone soy broth) in dry-heat thermal-resistant spore production by SSF. An experiment performed under optimum SSF conditions resulted in 1.9 x 10(10) CFU g(-1) dry matter with D (160 degrees C) = 5.2 +/- 0.2 min.
Sella
Sandra Regina B R
SR
Secretaria de Estado da Saúde do Paraná, Centro de Produção e Pesquisa de Imunobiológicos, Piraquara, PR, Brazil. sella.sandra@gmail.com
Dlugokenski
Regina Elizabete F
RE
Guizelini
Belquis P
BP
Vandenberghe
Luciana P S
LP
Medeiros
Adriane B P
AB
Pandey
Ashok
A
Soccol
Carlos Ricardo
CR
D001407:Bacillus / Q000254:growth & development*; D001681:Biological Assay; D018533:Biomass; D003470:Culture Media / Q000592:standards*; D005285:Fermentation; D008965:Molasses; D010461:Peptones; D013171:Spores, Bacterial / Q000254:growth & development*; D013242:Sterilization / Q000191:economics / Q000592:standards
D003470:Culture Media; D010461:Peptones