科研之友
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摘要
A novel cost-effective Bacillus atrophaeus Sterilization Bioindicator System (BIS) with a high quality and performance was developed from a soybean byproduct and compared with the commercial BIS. It was composed of recovery medium and dry-fermented spores with sand as the support. The BIS was developed and optimized using a sequential experimental design strategy. The recovery medium contained soluble starch (1.0 g/L), soybean molasses (30.0 g/L), tryptone (40.0 g/L), and bromothymol blue (0.02 g/L) at pH 8.5. The solid-state fermentation conditions of the bioreactor and environmental humidity had no significant effects on the spore yield and dry-heat resistance. The only substrate mineral that showed a positive effect was Mn2+, allowing Mg2+, K+, and Ca2+ to be eliminated from the formulation. Validation of optimized medium indicated D (160A degrees C) = 6.8 +/- 1.0 min (3.6 min more than the minimum) and spore yield = 2.3 +/- 0.5 x 10(9) CFU/g dry sand (10,000 x initial values). BIS performance resulted in D (160A degrees C) = 6.6 +/- 0.1 min. Sporulation and germination kinetics allowed the sporulation process to be reduced to three days, and the growth of heat-damaged spores was sufficient to achieve visual identification of a non-sterile BIS within 21 h. Process economics was a minimum of 23.9%, and process cycle time was reduced from 29 to 15 days. The new BIS parameters demonstrated compliance to all regulatory requirements. No studies have yet described a BIS production from soybean molasses.
- 出版日期2013-2
