PENGARUH MEDIA TERHADAP PERTUMBUHAN ISOLAT ACTINOMYCETES KODE AL35 SERTA OPTIMASI PRODUKSI METABOLIT ANTIBAKTERI BERDASARKAN WAKTU FERMENTASI DAN pH

Abstract

Actinomycetes is one of the microorganisms that can produce secondary metabolites such as antibiotics. An actinomycetes isolate (AL35) has been isolated from the rhizosphere of rice plants. The purpose of this study was to determine the effect of media on growth of AL35 isolate and optimization of antibacterial metabolite production based on fermentation time and pH. The growth medium used were ISP 1, ISP 2, ISP 3, ISP 4, ISP 5 and SNA. Growth of isolates was observed based on aerial mycelium and vegetative mycelium. Optimization of antibacterial metabolite production time was done by fermentation time of day 1 until day 14. Optimization was carried out at pH 5, 6, 7, 8, 9 and 10 with incubation time of 14 days. The antibacterial activity test method used was the well diffussion method. The parameter measured was the inhibitory zone diameter against Staphylococcus aureus and Escherichia coli around the well. The optimization profile of secondary metabolite production based on pH was analyzed using a graphic of the relation between pH and inhibitory zone diameter. Meanwhile based on the fermentation time, a graph of the relationship between fermentation time and inhibit zone was made. The results showed that AL35 isolate can grow on all media used with different fertility rates. The broth culture of AL35 isolates can inhibit the growth of S. aureus and E. coli. The medium that produced abundant growth rates of AL35 isolate from the most abundant were ISP4 media and ISP5, SNA, ISP2, ISP3, and ISP1. The fermentation time for antibacterial metabolite production was day 2, while the optimal pH was pH 9 based on activity against S. aureus and pH 6 against E. coli. Keywords