We described here the antibacterial action of eri sericin prepared by two different degumming
methods in the representative bacteria model of Gram-negative (E. coli) and Gram-positive (S.
aureus) by disc diffusion assay, critical-dilution micromethod, and by the effect of eri sericin
on bacterial growth. The 90-min 0.25% Na2CO3 degummed eri sericin was potent on E. coli,
while the 60-min water degummed eri sericin was potent on S. aureus. The action of potent eri
sericin was found to be bactericidal against growing cells. SEM micrographs illustrated
aberrant membrane morphology showing membrane dysfunction in both E. coli and S. aureus.
The potent eri sericin on S. aureus was especially shown to cause failures in the process of cell
division. This is the first reported evidence for the antibacterial action of eri sericin at the
cellular level.