Biofilm formation on the PLA and PHB films E. coli formed biofilm on the surface of PLA and PHB with PHMG derivatives (Fig. 3). The amount of biofilm on PLA and PHB with APHMG was similar to the amount observed on control samples (PLA and PHB without PHMG derivatives). In contrast, W-PHMG inhibited biofilm formation by E. coli on both PLA and PHB composites. At higher concentrations, the inhibitory effect of this PHMG derivative on biofilm formation by these bacteria was stronger. The amount of biofilm by S. aureus on the investigated composites was
lower (Fig. 4). A-PHMG introduced into PLA did not reduce the abundance of biofilm by S. aureus but introduced into PHB significantly inhibited biofilm formation by these bacteria. In contrast, W-PHMG in both PLA and PHB strongly inhibited biofilm formation by S. aureus; no biofilm formation by these bacteria was observed at concentrations of 0.6e1%.