Extraction and Identification of Secondary Metabolites from AL6 Isolates and Its Potential as Antibacterial against Escherichia coliABSTRACTSecondary metabolites in the form of antibiotics can be produced by rhizospheric bacteria. AL6 bacterial isolate, which is one of the bacterial isolates from the rhosphere of Saccarum officinarum L., is known to produce antibiotic compounds. This study aims to determine the activity of antibiotics from AL6 ethyl acetate extracts produced by AL6 bacterial isolates, to analyze the minimum inhibitory concentration (MIC) and the similarity of the active substances using GCMS. The ethyl acetate extract obtained was tested for MIC at 1.25%, 2.5%, 5.0%, 10.0%, 20%, and 40% concentrations. Detection of potential antibiotic spots was carried out using bioautographic thin layer chromatography (TLC). Compounds responsible for antibiotic activity were analyzed using GCMS. Minimum inhibitory levels obtained reached 2.5%. The active spots responsible for antibiotic activity against Escherichia coli at Rf 0.94. Components detected using GCMS and suspected to be antibiotics include chloroform; ethane, 1,1-dimethoxy-(CAS) dimethyl acetal; dan 1,3-dioxolane, 2-methoxymethyl-2,4,5-trimethyl.Keywords: AL6 bacterial isolate; antibiotic; Escherichia coli; GCMS; MICABSTRAKMetabolit sekunder berupa antibiotik dapat diproduksi oleh bakteri rizosfer. Isolat bakteri AL6, salah satu isolat bakteri dari rizosfer Saccarum officinarum L., diketahui dapat menghasilkan senyawa antibiotik. Penelitian ini bertujuan mengetahui aktivitas antibiotik dari ekstrak etil asetat antibiotik AL6 yang dihasilkan isolat bakteri AL6, menganalisis kadar hambat minimum (KHM), serta kemiripan zat aktif menggunakan GCMS. Ekstrak etil asetat yang diperoleh diuji KHM-nya pada konsentrasi 1,25%, 2,5%, 5,0%, 10,0%, 20%, dan 40%. Deteksi bercak yang berpotensi sebagai antibiotik dilakukan menggunakan kromatografi lapis tipis (KLT) bioautografi. Senyawa yang berperan dalam aktivitas antibiotik dianalisis menggunakan GCMS. Kadar hambat minimal yang diperoleh mencapai 2,5%. Hasil uji KLT bioautografi memperlihatkan bercak aktif sebagai antibiotik terhadap Escherichia coli pada Rf 0,94. Komponen senyawa yang terdeteksi menggunakan GCMS dan diduga sebagai antibiotik antara lain chloroform; ethane, 1,1-dimethoxy-(CAS) dimethyl acetal; dan 1,3-dioxolane, 2-methoxymethyl-2,4,5-trimethyl.