Growth profiles of E. coli (A) and S. aureus (B). Circle symbols represent the control growth while rectangular symbols are for the eri sericin treatment experiments with 90-
min 0.25% Na2CO3 degummed eri sericin (0.1 ตg/mL) for E. coli, and with the 60-min water degummed eri sericin (20 ตg/mL) for S. aureus.
SEM analysis of E. coli and S. aureus
The effect of eri sericin on bacterial cells was studied in E. coli and S. aureus as the representatives for Gram-negative and Gram-positive cells, respectively. Morphological investigations were performed with 15-h E. coli culture in the treatment of 90-min 0.25% Na2CO3 degummed eri sericin (0.1 ตg/mL), and with 15-h S. aureus culture in the treatment of 60-min water degummed eri sericin (20 ตg/mL). Control cells at 15-h culture were analyzed in parallel, which exhibited typical rod-like morphology of E. coli (Fig. 3A, 4A) and coccus morphology of S. aureus (Fig. 3C, 4C).