Electronic Theses and Dissertation

Bakteri endofit merupakan bakteri yang hidup di dalam jaringan tanaman tanpa menimbulkan gejala dan pengaruh langsung terhadap pertumbuhan tanaman. Bakteri endofit diketahui dapat menghasilkan metabolit sekunder yang mirip dengan inangnya. Tanaman singkong (Manihot esculenta Crantz) merupakan suatu tanaman dimana daunnya mengandung metabolit sekunder berupa alkaloid, flavonoid, saponin dan tanin yang mampu berperan sebagai antibakteri. Tujuan penelitian ini adalah mengetahui jumlah isolat, karakteristik serta untuk menguji aktivitas antibakteri dari bakteri endofit daun singkong. Aktivitas antibakteri diuji menggunakan metode difusi agar (Kirby-Bauer). Hasil isolasi diperoleh tujuh isolat bakteri endofit yang berhasil dimurnikan. Berdasarkan hasil pengamatan morfologi, pewarnaan Gram dan uji biokimia, isolat BEDS1 dan BEDS4 diduga berasal dari genus Pseudomonas, BEDS2 diduga dari genus Enterococcus, BEDS3, BEDS6 dan BEDS7 diduga termasuk ke dalam genus Bacillus, serta BEDS5 diduga berasal dari genus Salmonella. Isolat BEDS1 dan BEDS2 memiliki aktivitas antibakteri terhadap bakteri Staphylococcus aureus, sedangkan isolat BEDS7 memiliki aktivitas antibakteri terhadap seluruh bakteri uji yaitu Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, dan Streptococcus mutans.

Endophytic bacteria are bacteria that live in plant tissues without causing symptoms and have a direct effect on plant growth. Endophytic bacteria are known to produce secondary metabolites that are similar to the host. Cassava (Manihot esculenta Crantz) is a plant which its leaves contain secondary metabolites in the form of alkaloids, flavonoids, saponins and tannins which can act as antibacterials. The purpose of this study was to determine the number of isolates, characteristics and to test the antibacterial activity of cassava leaf endophytic bacteria. Antibacterial activity was tested using the agar diffusion method (Kirby-Bauer). The isolation results obtained seven isolates of endophytic bacteria that were successfully purified. Based on the results of morphological observations, Gram staining and biochemical tests, isolates BEDS1 and BEDS4 were thought to be from Pseudomonas genus, BEDS2 were thought to be from Enterococcus genus, BEDS3, BEDS6 and BEDS7 were thought to belong to the Bacillus genus, and BEDS5 were thought to be from Salmonella genus. BEDS1 and BEDS2 had antibacterial activity against Staphylococcus aureus bacteria, while BEDS7 isolates had antibacterial activity against all test bacteria namely Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Streptococcus mutans.