Degradation of dual-species biofilms using hydrolytic enzymes produced by Bacillus subtilis 170 strains

Ivo Ganchev and Georgi Dzhelebov
Trakia University, Faculty of Technics and Technologies of Yambol, 8602 Yambol, Bulgaria

Abstract

Ganchev, I. & Dzhelebov, G. (2024). Degradation of dual-species biofilms using hydrolytic enzymes produced by Bacillus subtilis 170 strains. Bulg. J. Agric. Sci., 30(2), 263–269

In this study, we evaluated the ability of enzymatic extracts produced by Bacillus subtilis 170 to remove multispecies biofilms, formed by the interaction of Bacillus subtilis and Escherichia coli strains. After culture in liquid medium, containing inorganic nitrogen sources, the bacterial hydrolytic extracts showed protease (250 U/mL) activity. Cell-free supernatants of B. subtilis 170 strains with proteolytic activity were the most effective, and promoted the complete removal of Bacillus subtilis and Escherichia coli dual-species biofilms. Of the treatments using cell-free supernatants of B. subtilis 170 with proteolytic enzyme activities with 250 U/mL, total biofilm degradation was observed for both dual-species biofilms in this study. The exoprotease secreted by B. subtilis 170 strain in the culture medium lead to a significant decrease in the biomass, average thickness, relative area of spread of biofilms formed with the participation of B. subtilis 170 and E. coli K-12 1655, B. subtilis 168 and E. coli K-12 1655 strains and strains is determined by their concentration. Thus, the hydrolases produced by Bacillus subtilis 170 strains evaluated here are highlighted as an interesting tool in the soil biofilm formation process and the potential ecological roles of soil biofilms.

Keywords: Rhizobacteria; protease; Bacillus subtilis 170; microbial biofilm

See the article as a PDF.