<![CDATA[Silver (Ag) in ionic form is toxic to microbial cells, but is environmentally friendly and safe for humans. This study aims to synthesize silver nanoparticles (AgNP) using Gram-positive bacterial isolate (B. firmus E65) as a bioreductor and to test its activity as an antimicrobial against Eschericia coli, Xanthomonas oryzae pv. oryzae (Xoo) and the fungus Colletotrichum gloeosporioides under in-vitro assays. AgNP was obtained by adding bacterial culture supernatant B. firmus E-65 to 5mM AgNO3 solution. The formation of AgNP was observed by changing the color of the solution after incubation at 37 °C for 72 hours. The UV-Vis spectrophotometer measurement to AgNP solution showed a maximum wavelength of 425 nm. The particle size of AgNP was 252.1 nm with intensity of 98.90 %. The result of bioassay against E. coli showed the greatest inhibition at 50 % AgNP (degree of inhibition (DI) =96.15 %), followed by 25 % AgNP (DI=76.92 %), and 12.5 % AgNP (DI=53.84 %). The bioassay against Xoo showed the greatest degree of inhibition was at AgNP 50 % (DI=92.85 %), followed by 25 % AgNP and 12.5 % AgNP (DI=85.71 %). Meanwhile bioassay against C.gloeosporioides, the greatest inhibition was observed at 25 % AgNP (DI=94.35 %), followed by 50 % AgNP (DI=91.9 %).]]>
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