Bacterial Colloids Silver from Slurry of Silver Craft Industry and Its Activity as an Antibacteria

Abstract

Colloidal silver is a mineral with a very small size (1-100 nm), accumulated in the form of mucus material on liquid waste from silver craft industry. Several species of bacteria from slurry of silver craft industry waste were tolerant and able to grow on the form of colloids. Bacterial colloids silver was formed concomitant with bacterial growth specific characters of bacterial resistance upon Ag+ ion. Colloidal silver is the most potential antiseptic and antimicrobial agent against viruses, bacteria, fungi and pathogenic microorganisms. The purpose of the study was to obtain resistant bacteria which synthesize colloids nano silver; and to elucidate their antibacterial activity against bacterial pathogen. The research was commenced with selection of silver tolerant bacteria from slurry of silver craft industry waste based on their growth ability on different AgNO3 concentration. Formation of bacterial colloids silver was observed through growth experiments using selected isolate grown on Triptone Yeast Extract (TYE) broth containing 0.1 mg/L AgNO3. The bacterial colloids silver formed was detected using laser. Results revealed that only one strain (BAgAK 6) grew on medium containing 5 mg/L AgNO3, and formed colloid mass. These colloids demonstrated as red line after exposed to laser beam. The bacterial colloids silver of BAgAK 6 inhibiting the growth of Escherichia coli FNCC 0091 and Staphylococcus aureus FNCC 0049 with inhibition index of 7.1 and 2.4, respectively. Conclusion of the research were strain BAgAK 6 resembled to Bacillus sp., resistant to a high concentration of Ag+ was able to form bacterial colloids silver, as antibacterial agent against to both gram negative and gram positive bacteria.