ISOLASI DAN SELEKSI BAKTERI PELARUT KALSIUM DARI TANAH HUTAN PENDIDIKAN WANAGAMA I YOGYAKARTA

SIWI PURWANINGSIH, Ir.Handojo Hadi Nurjanto, M.Agr.Sc.

2014 | Skripsi | KEHUTANAN

Bakteri mampu memproduksi asam-asam organik yang dapat melapukkan batuan dalam proses pembentukan tanah. Tanah Hutan Wanagama I berasal dari batuan induk gamping (CaCO3) yang mudah larut dengan asam. Bakteri dapat mempercepat proses pembentukan tanah di Hutan Wanagama I melalui pelarutan batuan gamping oleh asam-asam yang dihasilkan bakteri. Penelitian ini dilakukan dengan tujuan untuk mendapatkan isolat bakteri yang memiliki kemampuan melarutkan kalsium di Hutan Pendidikan Wanagama I Yogyakarta. Penelitian dilakukan di Laboratorium Fisiologi dan Tanah Hutan Fakultas Kehutanan UGM. Sumber inokulum berasal dari bawah tegakan jati, gamal dan rumput yaitu alang-alang (Imperata cylindrica) dan rumput grintingan (Cynodon dactylon) di petak 5 dan petak 17 Hutan Wanagama I. Kemampuan bakteri dalam melarutkan kalsium ditandai dengan pembentukan zona bening pada media yang mengandung serbuk kapur. Identifikasi dilakukan terhadap sifat morfologi dan biokimia. Hasil isolasi didapatkan 61 isolat, terdiri dari 27 jenis bakteri dengan morfologi koloni yang berbeda. Pada petak 5 ditemukan 30 isolat dan petak 17 ditemukan 31 isolat. Berdasarkan hasil seleksi didapatkan 10 isolat yang memilliki kemampuan melarutkan kalsium. Isolat I3 membentuk rasio zona jernih dan diameter koloni bakteri terbesar yaitu 3,83 diikuti oleh G1 sebesar 3,49. Isolat-isolat bakteri pelarut kalsium yang diseleksi memiliki bentuk sel bulat bersifat gram negatif, memiliki morfologi koloni bervariasi: bulat, curled, irreguler, rhizoid, dengan elevasi cembung, umbronate dan raised. Isolat bakteri memiliki kemampuan menghasilkan asam dan gas yang berbeda-beda

Bacteria excretes organic acids that can degrade rocks, therefore facilitated soil formation. Wanagama I forest soil derived from limestone (CaCO3) which solubilize easily in the presence of acid. Bacteria can accelerate the process of soil formation in Wanagama I through dissolution of limestone by acids produced by bacteria. This research was conducted to obtain bacterial isolates that are capable of solubilizing calcium from Wanagama I forest soil. The study was conducted at the Laboratory of Physiology and Forest Soil Faculty of Forestry The University of Gadjah Mada. The source of inoculum was taken from soil under stand of teak and gamal, and soil covered with grass Imperata cylindrica and Cynodon dactylon in compartment 5 and 17. The ability of bacteria to dissolve calcium was characterized by the formation of a clear zone on media containing lime powder. Identification was carried out based on morphological and biochemical characteristics. The isolation was obtained 61 isolates that consisted of 27 isolates based on colony morphological differences. Thirty isolates were found in compartment 5 and 31 isolates were found in compartment 17. After the selection, there were 10 isolates capable of dissolving calcium. Isolates I3 formed the highest ratio between clear zone and diameter of bacteria colonies (3.83) followed by G1 that was 3.49. The selected calcium solubilizing bacteria had coccus cells, gram-negative. The bacteria colony morphology varied from round, curled, irregular, rhizoid, with a convex elevation, umbronate to raised. They had ability to produce acid and gas differently

Kata Kunci : pelapukan batuan, bakteri, kalsium, kapur, Wanagama I