Electronic Theses and Dissertation

Kawasan Geotermal Jaboi, Kota Sabang merupakan kawasan dengan lingkungan ekstrem yang kaya senyawa sulfur akibat aktivitas vulkanik, sehingga berpotensi menjadi habitat Bakteri Pengoksidasi Sulfur (BPS). Penelitian ini bertujuan menghitung jumlah koloni BPS dan menganalisis korelasinya dengan konsentrasi SO2 atmosfer berdasarkan data Sentinel-5P, serta mengidentifikasi karakteristik morfologi makroskopis dan mikroskopis isolat BPS dari kawasan tersebut. Pengambilan sampel dilakukan menggunakan metode stratified random sampling berdasarkan distribusi SO2 hasil analisis Sentinel-5P melalui Google Earth Engine (GEE) dengan membagi kawasan menjadi tiga zona, Zona Hijau (0,002–0,1 ppm), Zona Kuning (0,1–0,3 ppm), dan Zona Merah (0,3–0,8 ppm). Isolasi BPS dilakukan menggunakan media Thiosulfate Mineral Agar dengan metode spread plate dan dihitung menggunakan Total Plate Count (TPC). Total koloni BPS yang berhasil diisolasi sebanyak 442 koloni, dengan distribusi tertinggi pada Zona Kuning (334 koloni), diikuti Zona Merah (76 koloni) dan Zona Hijau (32 koloni). Hubungan antara konsentrasi SO2 dengan jumlah koloni BPS bersifat non-linear, dengan kondisi optimum pertumbuhan pada konsentrasi SO2 sedang. Faktor suhu (30–35oC) dan pH netral (6–7) turut mendukung pertumbuhan optimal BPS. Sebanyak 25 isolat murni berhasil diperoleh dengan karakteristik makroskopis yang didominasi koloni berwarna putih, berbentuk bundar, bertepian licin dan berelevasi datar. Secara mikroskopis, bentuk sel coccus mendominasi (56%) dengan mayoritas bersifat Gram negatif (52%). Hasil penelitian ini memberikan informasi dasar mengenai keragaman dan persebaran BPS di kawasan geotermal.

Kata kunci: Bakteri Pengoksidasi Sulfur, Kawasan Geotermal Jaboi, Morfologi Bakteri, Sentinel-5P, Sulfur Dioksida (SO2).

The Jaboi Geothermal Area, Sabang City, is an extreme environment rich in sulfur compounds due to volcanic activity, making it a potential habitat for Sulfur-Oxidizing Bacteria (SOB). This study aimed to enumerate SOB colonies and analyze their correlation with atmospheric SO₂ concentrations based on Sentinel-5P data, as well as to identify the macroscopic and microscopic morphological characteristics of SOB isolates from the area. Sampling was conducted using a stratified random sampling method based on SO₂ distribution derived from Sentinel-5P analysis via Google Earth Engine (GEE), dividing the area into three zones: the Green Zone (0.002–0.1 ppm), the Yellow Zone (0.1–0.3 ppm), and the Red Zone (0.3–0.8 ppm). SOB isolation was performed using Thiosulfate Mineral Agar medium with the spread plate method, and colony counts were determined using the Total Plate Count (TPC) method. A total of 442 SOB colonies were successfully isolated, with the highest distribution recorded in the Yellow Zone (334 colonies), followed by the Red Zone (76 colonies) and the Green Zone (32 colonies). The relationship between SO₂ concentration and SOB colony count was non-linear, with optimal growth occurring at moderate SO₂ concentrations. Temperature (30–35°C) and near-neutral pH (6–7) also supported optimal SOB growth. A total of 25 pure isolates were obtained, with macroscopic characteristics predominantly showing white, circular colonies with smooth margins and flat elevation. Microscopically, coccus cell morphology was dominant (56%), with the majority being Gram-negative (52%). The findings of this study provide baseline information on the diversity and distribution of SOB in geothermal environments. Keywords: Bacterial Morphology, Geothermal Area Jaboi, Sentinel-5P, Sulfur Dioxide (SO₂), Sulfur-Oxidizing Bacteria.