Potensi Bakteri Penghasil Esterase pada Gastrointestinal Ikan Nila (Oreochromis Niloticus) yang Terkontaminasi Mikroplastik

Jenevelin, Yemima (2026) Potensi Bakteri Penghasil Esterase pada Gastrointestinal Ikan Nila (Oreochromis Niloticus) yang Terkontaminasi Mikroplastik. Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Pencemaran mikroplastik telah menjadi permasalahan global yang memberikan dampak terhadap ekosistem perairan, termasuk perubahan struktur komunitas mikrobiota pada saluran gastrointestinal ikan. Mikroorganisme yang beradaptasi pada lingkungan tersebut berpotensi menghasilkan Esterase, yaitu enzim hidrolase yang mengkatalisis pemutusan ikatan ester dan berpotensi dimanfaatkan dalam hidrolisis senyawa berbasis ester. Penelitian ini bertujuan untuk mengisolasi dan mengkarakterisasi bakteri penghasil Esterase dari saluran gastrointestinal ikan nila (Oreochromis niloticus) yang terkontaminasi mikroplastik serta menentukan kondisi optimum produksi Esterase menggunakan metode submerged fermentation (SmF). Isolasi bakteri dilakukan dari saluran gastrointestinal ikan nila, kemudian diseleksi berdasarkan pembentukan zona hidrolisis pada media selektif Esterase. Isolat dengan indeks hidrolitik tertinggi diproduksi menggunakan metode SmF pada variasi pH 7, 8, dan 9. Aktivitas Esterase ditentukan menggunakan metode Cupric Acetate-Pyridine (CAPR) dengan substrat minyak kelapa berdasarkan jumlah asam laurat yang terbentuk, sedangkan karakterisasi dilakukan melalui pengukuran kadar protein menggunakan metode Bradford, aktivitas spesifik, dan titik isoelektrik. Data dianalisis secara deskriptif eksploratif melalui perbandingan aktivitas Esterase, kadar protein, aktivitas spesifik, dan titik isoelektrik pada setiap perlakuan pH. Hasil penelitian menunjukkan bahwa isolat G2 memiliki indeks hidrolitik tertinggi dan menghasilkan aktivitas Esterase optimum pada pH 7 dengan aktivitas kasar sebesar 13,13 U/mL pada waktu inkubasi 10 jam. Setelah dilakukan purifikasi parsial menggunakan fraksinasi amonium sulfat, fraksi 40–60% menghasilkan aktivitas Esterase sebesar 59,25 U/mL, kadar protein 0,73 mg/mL, dan aktivitas spesifik 81,65 U/mg, lebih tinggi dibandingkan perlakuan pH 8 dan pH 9. Hasil tersebut menunjukkan bahwa pH 7 merupakan kondisi optimum untuk produksi Esterase oleh isolat G2. Esterase yang dihasilkan berpotensi dikembangkan sebagai biokatalis dalam hidrolisis senyawa berbasis ester dan menjadi kandidat untuk penelitian lanjutan mengenai biodegradasi mikroplastik.
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Microplastic pollution has become a global environmental issue that adversely affects aquatic ecosystems, including alterations in the microbial community structure of the fish gastrointestinal tract. Microorganisms that adapt to this environment have the potential to produce Esterase, a hydrolase enzyme that catalyzes the hydrolysis of ester bonds and has potential applications in the hydrolysis of ester-based compounds. This study aimed to isolate and characterize Esterase-producing bacteria from the gastrointestinal tract of Nile tilapia (Oreochromis niloticus) contaminated with microplastics and to determine the optimum conditions for Esterase production using the submerged fermentation (SmF) method. Nile tilapia samples were collected from aquaculture ponds in Benowo District, Surabaya City, East Java, Indonesia. Bacterial isolates were obtained from the gastrointestinal tract of Nile tilapia and screened based on the formation of hydrolysis zones on an Esterase-selective medium. The isolate with the highest hydrolytic index was cultured using the SmF method at pH 7, 8, and 9. Esterase activity was determined using the Cupric Acetate–Pyridine (CAPR) method with coconut oil as the substrate by measuring the amount of lauric acid released. Enzyme characterization included protein content determination using the Bradford method, specific activity, and isoelectric point analysis. Data were analyzed using a descriptive-exploratory approach by comparing Esterase activity, protein content, specific activity, and isoelectric point among different pH treatments. The results showed that isolate G2 exhibited the highest hydrolytic index and achieved optimum Esterase production at pH 7, with a crude Esterase activity of 13.13 U/mL after 10 h of incubation. Following partial purification by ammonium sulfate fractionation, the 40–60% saturation fraction exhibited the highest Esterase activity (59.25 U/mL), protein content (0.73 mg/mL), and specific activity (81.65 U/mg). In addition, the Esterase exhibited an isoelectric point within the pH range of 5–6. These findings indicate that pH 7 is the optimum condition for Esterase production by isolate G2, while the 40–60% ammonium sulfate fraction is the most suitable fraction for obtaining Esterase with the highest activity and relative purity. The Esterase produced by isolate G2 has the potential to be developed as a biocatalyst for the hydrolysis of ester-based compounds and represents a promising candidate for further studies on microplastic

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Bakteri, Esterase, Ikan nila (Oreochromis niloticus), Mikroplastik, Submerged fermentation.Esterase, Bacteria, Microplastics, Nile tilapia (Oreochromis niloticus), Submerged fermentation.
Subjects:	Q Science Q Science > Q Science (General) Q Science > QH Biology > QH301 Biology Q Science > QH Biology > QH541 Ecology
Divisions:	Faculty of Science and Data Analytics (SCIENTICS) > Biology > 46201-(S1) Undergraduate Thesis
Depositing User:	Yemima Jenevelin
Date Deposited:	27 Jul 2026 06:48
Last Modified:	27 Jul 2026 06:48
URI:	http://repository.its.ac.id/id/eprint/137972

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