AAAR 34th Annual Conference
October 12 - October 16, 2015
Hyatt Regency
Minneapolis, Minnesota, USA
Abstract View
Inactivation of Aerosolized Bacillus Thuringiensis Spores by Combustion of Powderized Materials Containing Boron and Iodine
SERGEY A. GRINSHPUN, Michael Yermakov, Reshmi Indugula, Tiina Reponen, Edward Dreizin, Mirko Schoenitz, University of Cincinnati
Abstract Number: 55 Working Group: Environmental Fate of Infectious Aerosols
Abstract An explosion or fire at a bio-weapon facility may release highly pathogenic bio-agents into the atmosphere. Some especially resistant species such as Bacillus anthracis spores can remain viable even after exposure to extensive heat and chemicals. As part of the bio-agent defeat program, novel reactive materials are being developed to neutralize stress-resistant viable microorganisms during their release. In this effort, we tested two materials, Mg•Al•I$_2 and Al•B•I$_2 prepared using high-energy mechanical milling, with respect to the biocidal capability of their combustion products against Bacillus thuringiensis kurstaki (Btk) spores – a well-established surrogate of Bacillus anthracis. A state-of-the-art experimental facility was used to investigate the survival of aerosolized spores. Both powderized materials are capable of retaining substantial quantities of iodine stabilized in the metal matrix and released upon heating in a combustion environment. The spores were dispersed in dry airflow and exposed to the tested combustion products in a temperature-controlled environment. The bioaerosol inactivation factor was determined as a function of the aerosolized powder concentration that ranged from 0 to about 40 mg/L. For both materials, the inactivation factor increased exponentially with the powder concentration. Both materials having the same weight ratio (40:40:20) showed statistically the same inactivation capabilities. It was demonstrated that the main reason of the spore viability loss observed in the tests was the spore interaction with iodine in the air flow rather than exposure to heat. Boron was found to enhance the inactivation. The data generated in this study help understand the kinetics of the spore inactivation by combustion products of halogen-containing reactive materials. The effort also creates the foundation for developing new materials for efficient neutralization of viable microorganisms in combustion environments.
The authors thank the U.S. Defense Threat Reduction Agency for funding and Dr. Su Peiris for fruitful discussions.