Antibacterial activity of Bombyx mori and Samia cynthia ricini sericin proteins against Escherichia coli and Staphylococcus aureus

ABSTRACT

Aims@#This study was designed to investigate the antibacterial properties of the sericin protein Bombyx mori and Samia cynthia ricini against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus strains.@*Methodology and results@#Sericin protein was extracted from the cocoons of B. mori races A, B, C, D, F1-1, F1-2 and S. ricini from Indonesia using a degumming process. The extracted sericin protein was evaluated as anti-microbials using Kirby Breuer disc diffusion, spectrometer measurement in decreasing OD value and imaging scanning electron microscope (SEM). The tests revealed that sericin protein from B. mori was more capable of inhibiting bacteria S. aureus than E. coli. Sericin protein from S. ricini was also capable of strongly inhibiting both S. aureus and E. coli bacteria. The sericin proteins of B. mori and S. ricini were found to reduce the number of S. aureus and E. coli bacteria as the OD value decreased at a concentration of 9%. The SEM imaging suggests that sericin B. mori and S. ricini proteins caused changes in cell morphology in S. aureus and E. coli bacteria, resulting in bacterial cell function disruption and death.@*Conclusion, significance and impact of study@#Bombyx mori and S. ricini sericin proteins were found to act against S. aureus and E. coli bacteria. Therefore, sericin protein has a greater antibacterial activity against Gram-positive strain S. aureus.