Electronic Theses and Dissertation

Biosurfaktan adalah metabolit sekunder yang diproduksi oleh bakteri sebagai produk ekstraseluler memiliki gugus hidrofilik dan hidrofobik yang berperan dalam menurunkan tegangan permukaan. Penelitian ini bertujuan untuk mengisolasi bakteri penghasil biosurfaktan dan mengkarakterisasi isolat potensial penghasil biosurfaktan dari batubara. Sebanyak 47 koloni bakteri berhasil diisolasi dari batubara, dan sepuluh isolat yang menghasilkan koloni biru gelap berdasarkan uji CTAB untuk mengidentifikasi kemampuan produksi biosurfaktan. Skrining isolat potensial penghasil biosurfaktan dilakukan dengan metode uji Parafilm M, uji drop-collapse, uji perpindahan minyak, uji indeks emulsifikasi, dan pengukuran tegangan permukaan. Hasil skrining menunjukkan dua isolat potensial penghasil biosurfaktan, yaitu BB1 dan BB10. Kedua isolat dilakukan identifikasi morfologi dan pewarnaan Gram. Isolat BB1 merupakan bakteri Gram negatif dengan bentuk sel basil, memiliki indeks emulsifikasi terhadap toluena 46,4%, n-heksan 22,4%, dan minyak tanah 34,4%, serta tegangan permukaan 56,61 dyne/cm. Isolat BB10 juga bakteri Gram negatif dengan bentuk sel basil, dengan indeks emulsifikasi terhadap toluena 37,2%, n-heksan 16%, dan minyak tanah 29,2%, serta tegangan permukaan 52,84 dyne/cm. Berdasarkan hasil tersebut, bakteri penghasil biosurfaktan berhasil diisolasi dari batubara.

Biosurfactants are secondary metabolites produced by bacteria as extracellular products, possessing both hydrophilic and hydrophobic groups that function to reduce surface tension. This study aims to isolate biosurfactant-producing bacteria and characterize potential isolates from coal. A total of 47 bacterial colonies were successfully isolated from coal, and ten isolates that produced dark blue colonies based on the CTAB assay were selected to identify biosurfactant production capabilities. Screening of potential biosurfactant-producing isolates was carried out using the Parafilm M test, drop-collapse test, oil displacement test, emulsification index test, and surface tension measurement. The screening result identified two potential biosurfactant producing isolates, namely BB1 and BB10. Both of isolates were subjected to morphological and Gram staining. Isolate BB1 is a Gram-negative, rod-shaped bacterium with an emulsification index of 46.4% against toluene, 22.4% against n-hexane, and 34.4% against kerosene, with a surface tension of 56.61 dyne/cm. Isolate BB10 is also a Gram-negative, rod-shaped bacterium, showing an emulsification index of 37.2% against toluene, 16% against n-hexane, and 29.2% against kerosene, with a surface tension of 52.84 dyne/cm. Based on these results, biosurfactant-producing bacteria were successfully isolated from coal.