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Aims: To evaluate a sodium hypochlorite and hydrogen peroxide solution (Ox-B7) as a potential decontaminant of Bacillus subtilis spore-contaminated surface materials (porous and nonporous)., Methods and Results: Test materials were contaminated with B. subtilis spores to a final concentration in the range of 5.7-6.6 log CFU cm(-2). Ox-B7 reduced spore counts by 99.999% (5 log) for both porous and nonporous surfaces within a 5-min contact. Treatment with equivalent concentrations of only sodium hypochlorite reduced spore counts by 99% (2 log) on porous materials and by 99.99% (4 log) on nonporous materials. Hydrogen peroxide treatments reduced spores by less than 90% (<1 log) on both porous and nonporous materials when compared with untreated samples., Conclusions: A combination of sodium hypochlorite and hydrogen peroxide (Ox-B7) effectively killed B. subtilis spores on both porous and nonporous surface materials., Significance and Impact of the Study: The combination of sodium hypochlorite and hydrogen peroxide can be used as an alternative disinfectant of spore-contaminated surface materials, as it is more effective than when hydrogen peroxide or sodium hypochlorite are used separately.

A derepressed and partially constitutive mutant for dextranase of Lipomyces starkeyi was selected after ethyl methane sulphonate mutagenesis by zone clearance on blue dextran agar plates. The mutant produced dextranase when grown on glucose, fructose and sucrose as well as on dextran, and more enzyme was produced by the mutant than by the parental strain when grown on 1% dextran. The pH and temperature optima for the mutant dextranase were 5.5 and 55 degrees C, respectively. Dextranase produced on sucrose produced more isomaltose and less glucose after dextran hydrolysis than the equivalent enzyme produced on dextran. The clinical size dextran (average mol. wt of 75,000 +/- 25,000) yield of mixed culture fermentation with the mutant and Leuconostoc mesenteroides was 94% of the total dextran produced.