Keragaman Bakteri Pengoksidasi Sulfur Secara Culturable dan Unculturable di Sumber Air Panas Candi Gedong Songo

MUHAMAD NASTAIN, Dr. Endah Retnaningrum, M.Eng

2021 | Tesis | MAGISTER BIOLOGI

Sumber daya alam logam mangan (Mn) di Indonesia memiliki banyak potensi sebagai bahan baku industri metalurgi maupun non metalurgi. Proses ekstraksi bijih Mn selama ini tidak ramah lingkungan karena membutuhkan asam dan biaya yang tinggi. Salah satu penekan biaya tinggi dengan dilakukan bioleaching bijih Mn berdasarkan keasaman. Isolasi diperlukan untuk memperoleh isolat bakteri pengoksidasi sulfur (BOS) yang mampu melakukan bioleaching logam Mn. Analisis metagenomik juga diperlukan untuk melihat peran konsorsium mikrobia secara keseluruhan terutama bakteri unculturable dalam mengoptimumkan proses bioleaching. Tujuan penelitian ini adalah untuk mendapatkan konsorsium bakteri pengoksidasi sulfur secara culturable dan unculturable dalam melakukan bioleaching bijih Mn. Isolat bakteri pengoksidasi sulfur diambil dari sumber air panas Candi Gedong Songo Ungaran. Sampel sedimen diambil untuk mendapatkan total genom dan selanjutnya dilakukan analisis metagenomik 16S rRNA amplicon sequencing sehingga didapatkan konsorsium bakteri pengoksidasi sulfur secara unculturable. Sedangkan untuk mendapatkan konsorsium bakteri secara culturable dilakukan dengan isolasi bakteri dengan ditumbuhkan dalam media selektif 9K yang diberi logam Mn. Kemampuan pertumbuhan isolat yang mampu tumbuh pada media 9K diukur dengan spektrofotometer UV-Vis. Pengukuran aktivitas bioleaching bijih Mn dilakukan dengan menggunakan atomic absorption spectrophotometry (AAS) selama 18 hari dengan diberi tween-80. Hasil analisis metagenomik amplicon 16S rRNA pada sampel sumber air panas menunjukkan terdapat 4 spesies BOS yang dominan yaitu Ralstonia solanacearum, Acidimicrobiom ferroxidans, Staphylococcus pasteuri, dan Leptospirillum ferriphilum. Aktivitas bioleaching tertinggi didapatkan pada sampel MN2 hari ke-15 dengan nilai efisiensi bioleaching sebesar 24,16%. Hasil konstruksi filogeni menunjukkan bahwa isolat MN1B merupakan bakteri yang memiliki kecenderungan atau teridentifikasi Stapphylococcus pasteuri.

Manganese (Mn) natural resources in Indonesia have a lot of potential as raw materials for metallurgical and non-metallurgical industries. Mn ore extraction process so far is not environmentally friendly because it requires acid and high costs. One way to reduce high costs is by bioleaching Mn ore based on acidity. Isolation is needed to obtain sulfur oxidizing bacteria (SOB) isolates capable of bioleaching of Mn metal. Metagenomic analysis is also needed to see the role of the microbial consortium as a whole, especially unculturable bacteria, in optimizing the bioleaching process. The purpose of this study was to obtain a consortium of culturable and unculturable sulfur oxidizing bacteria for bioleaching of Mn ore. Sulfur oxidizing bacteria isolates were taken from the hot springs of Gedong Songo Ungaran Temple. Sediment samples were taken to obtain the total genome and then performed metagenomic analysis of 16S rRNA amplicon sequencing to obtain a consortium of unculturable sulfur oxidizing bacteria. Meanwhile, to obtain a culturable bacterial consortium, the bacteria were isolated by growing them in 9K selective media which was added with Mn metal. The growth ability of isolates capable of growing on 9K media was measured by UV-Vis spectrophotometer. The bioleaching activity of Mn ore was measured using atomic absorption spectrophotometry (AAS) for 18 days with tween-80. The results of the metagenomic analysis of 16S rRNA amplicons in hot spring samples showed that there were 4 dominant SOB species, namely Ralstonia solanacearum, Acidimicrobiom ferroxidans, Staphylococcus pasteuri, and Leptospirillum ferriphilum. The highest bioleaching activity was found on the 15th day of MN2 sample with a bioleaching efficiency value of 24.16%. The results of the phylogeny construction showed that the MN1B isolate was a bacterium that had a tendency or was identified as Stapphylococcus pasteuri.

Kata Kunci : bakteri pengoksidasi sulfur, bioleaching, mangan, metagenomik