РН Homeostasis During Dual-Species Biofilm Formation by Bacillus subtilis and Escherichia coli Strains

In a large part of ecological niches, bacterial species are united in communities and develop together in the form of heterogeneous structures called biofilms, which are formed on surfaces of different nature and nature with the participation and as a result of the interaction of two or more bacterial species. The main objective of the present work is to study the effects of pH-value in the culture medium on the biofilm development and architecture of biofilms of the bacterium (B. subtilis) during their interactions with Escherichia coli K-12 1655 strain. Effects of pH-value in the culture medium on bacterial biofilm formation and the mechanisms were analyzed by the crystal violet staining method combined with cultivated microbial analysis, and confocal laser scanning microscopy. In the presence of phosphate at pH-value of pH 6,0 , the bacterial growth rates of single-species biofilms of Bacillus subtilis strains and biofilms as result of their interaction with Escherichia coli strains were similar and determines the mutualism between two strains in the structure of biofilms, formed by the participation of B.subtilis 170 and E.coli K-12 1655, B.subtilis 168 and E.coli K-12 1655 strains. Considering that static growth in a biofilm is a highly relevant growing state for many soil bacteria, more research on phosphate acquisition and pH homeostasis by model soil bacteria in static cultures is required to draw a more comprehensive picture of the role of biofilm production in phosphate use efficiency and pH homeostasis.