DEVELOPING NOVEL APPROACHES TO MITIGATE BIOFILM FORMATION BY NEWLY IDENTIFIED DAIRY ASSOCIATED BACILLUS STRAINS

Introduction. Microbial damages, caused by biofilm-forming bacteria in the dairy industry, are a fundamental threat to safety and quality of milk products. Preventing biofilm formation is considered as more desirable option than treating it, and a wide range of anti-biofilm approaches has been proposed for this purpose. However, the effectiveness of anti-biofilm approaches is usually evaluated using laboratory strains that are often characterized by weak biofilm forming capacity due to domestication process. Therefore using relevant strains, obtained from natural industrial conditions, for evaluating anti-biofilm approaches is of significant importance.

In order to develop an appropriate model to examine anti-biofilm approaches, we identified and characterized several Bacillus strains, which are among the most problematic dairy biofilm formers, isolated from the dairy associated environment.

Methods. Bacillus isolates were identified using whole genome sequencing according to Illumina sequencing method. Biofilm formation in milk by the tested strains was examined using constant depth film fermenter (CDFF). Biofilms were analyzed with the help of Olympus IX81 confocal laser scanning microscope. Evaluation of anti-biofilm approaches was performed using the CDFF and recently developed cleaning-in-place model system.

Results. According to our results, the tested strains are characterized by aggressive biofilm formation in milk at different conditions relevant to the dairy associated environment. We further report about the development of different anti-biofilm approaches using isolates characterized with the strongest biofilm formation.

Conclusions. In overall, the results show that newly identified Bacillus isolates provide a relevant and robust model for determining the effectiveness of anti-biofilm approaches in context of the dairy industry.

This work was partially supported by the grant 421-0306-16 from the Chief Scientist of the Ministry of Agriculture.