Rhamnolipid assessment
Rhamnolipid production was quantified using the
Blue Agar Plate (Bap) method,
following a previously established procedure (Bhat et al., 2015). The
detection of rhamnolipid was conducted using a mineral salt agar medium
supplemented with 2% glucose, 0.05% cetyltrimethylammonium bromide,
and 0.02% methylene blue. Each treatment utilized a 0.5 McFarland’s
suspension prepared from 24-hour bacterial culture, to which sterile
chitosan was added in concentrations of 10 and 100 μg/L. Cork borers
were used to create 4 mm diameter wells on methylene blue agar plates,
which were then loaded with 30 μL of fresh culture from individual
isolates. The plates were incubated at 37°C for 48-72 hours. Positive
results were observed as a dark blue halo zone around the culture and
assessed using a transilluminator at a wavelength of 365 nm.