The biosafety evaluation of natural Bacillus spp. strains with valuable biotechnological properties

Background. The modern trend in the agriculture development is its greening through the use of microorganisms that have a range of useful properties (antagonistic activity, enzyme production, etc.). An important selection criterion for the inclusion of microbes in the composition of biopreparations is their safety. Purpose. The present study aimed to investigate the safety of Bacillus spp. natural strains that possessing valuable biotechnological properties. Material and methods. The objects of the study were 10 bacillus strains from the collection of the Engineering Center "Prombiotech" ASU. The strains were tested for: the ability to produce pathogenicity enzymes using classical microbiological methods (hemolytic, phosphatase, lecithinase and ribonuclease activity), the profile of genes synthesizing enterotoxins and cereulide synthetase of emetic toxin (cytK, hblC, entFM, nheA, ces) using the real-time PCR test system, and the ability of the studied bacillus strains toxicity on a mouse model. Results. All the studied Bacillus spp. strains showed at least one enzymatic activity (RNAase). For the species B. pumilus, B. toyonensis and the B. licheniformis 6 strain, 3 out of 4 positive enzymatic tests were detected (except for lecithinase). According to the real-time PCR data, all the studied strains showed a negative result for five toxin genes. This was confirmed in vivo, since no acute toxic effect was recorded in the experimental mice from the action of the all the studied Bacillus spp. strains supernatants. Conclusion. The studied genus Bacillus strains do not belong to potential pathogens of food poisoning in humans and animals, since they do not produce enterotoxins and cereulide, and do not exhibit toxic properties in a mouse model.