'Aini, Arummitha Qurrotu (2026) Analisis Perubahan Morfologi Dan Sifat Optik Cu₂O Quantum Dots Pasca Biokonjugasi Dengan Xilanase– Bacillus Amyloliquefaciens Pada Aplikasi Nanobiofertilizer. Other thesis, Institut Teknologi Sepuluh Nopember.
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Abstract
Peningkatan kebutuhan pangan global mendorong pengembangan pupuk yang lebih efisien dan ramah lingkungan, salah satunya melalui pemanfaatan nanobiofertilizer. Penelitian ini bertujuan mengkaji karakteristik morfologi dan perubahan sifat optik Cu₂O quantum dots (QDs) sebelum dan sesudah biokonjugasi dengan Bacillus amyloliquefaciens dan enzim xilanase. Cu₂O QDs disintesis menggunakan metode wet chemical (hot-soap method) dan menghasilkan ukuran kristalit sekitar ±8 nm berdasarkan XRD serta ukuran partikel rata-rata ±8–9 nm berdasarkan TEM. Hasil FESEM menunjukkan Cu₂O murni mengalami aglomerasi, sedangkan setelah biokonjugasi partikel terdistribusi pada matriks biologis bakteri. Spektrum FTIR menunjukkan pita khas Cu–O (500–700 cm⁻¹) serta munculnya gugus fungsi biologis setelah biokonjugasi. Karakterisasi UV–Vis dan Tauc plot menunjukkan energi celah pita Cu₂O QDs berada pada kisaran ±2,3–2,4 eV, yang bergeser ke energi lebih tinggi setelah biokonjugasi. Hasil photoluminescence (PL) menunjukkan quenching fluoresensi disertai percepatan PL lifetime dari orde 10⁻⁸ s menjadi 10⁻⁹ s. Pengujian ROS menggunakan metode TiOSO₄ menunjukkan Cu₂O murni menghasilkan H₂O₂ tertinggi dengan absorbansi 4,716 a.u., sedangkan sistem biokonjugasi menurun menjadi 1,387 a.u. (CuBa 12,5) dan 1,475 a.u. (CuBa 25). Hasil ini menunjukkan bahwa biokonjugasi mampu mengendalikan sifat optik dan aktivitas redoks Cu₂O QDs, sehingga berpotensi diaplikasikan sebagai nanobiofertilizer yang lebih stabil dan aman.
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The increasing global demand for food has driven the development of more efficient and environmentally friendly fertilizers, including nanobiofertilizers. This study aims to investigate the morphological characteristics and optical property changes of Cu₂O quantum dots (QDs) before and after bioconjugation with Bacillus amyloliquefaciens and xylanase enzyme. Cu₂O QDs were synthesized using a wet chemical hot-soap method, yielding crystallite sizes of approximately ±8 nm based on XRD analysis and average particle sizes of ±8–9 nm from TEM observations. FESEM analysis revealed agglomeration in pristine Cu₂O, while bioconjugated samples showed improved particle distribution within the bacterial matrix. FTIR spectra exhibited characteristic Cu–O bands (500–700 cm⁻¹) along with the emergence of biological functional groups after bioconjugation. UV–Vis spectroscopy and Tauc plot analysis indicated a band gap of ±2.3–2.4 eV for pristine Cu₂O QDs, which shifted toward higher energy after bioconjugation. Photoluminescence (PL) measurements showed fluorescence quenching accompanied by a reduction in PL lifetime from the order of 10⁻⁸ s to 10⁻⁹ s. Reactive oxygen species (ROS) analysis using the TiOSO₄ method demonstrated that pristine Cu₂O produced the highest H₂O₂ level with an absorbance of 4.716 a.u., while bioconjugated systems exhibited significantly lower values of 1.387 a.u. (CuBa 12.5) and 1.475 a.u. (CuBa 25). These results indicate that bioconjugation effectively regulates the optical and redox properties of Cu₂O QDs, highlighting their potential for stable and safe nanobiofertilizer applications.
| Item Type: | Thesis (Other) |
|---|---|
| Uncontrolled Keywords: | Bacillus amyloliquefaciens, Biokonjugasi, Cu₂O QDS, Nanobiofertilizer, Quantum Dots, Bacillus amyloliquefaciens, Bioconjugation, Cu₂O, NanoBiofertilizer, Quantum Dots |
| Subjects: | Q Science > QR Microbiology > QR74.8 Bacteria S Agriculture > S Agriculture (General) > S633.5 Fertilizers S Agriculture > S Agriculture (General) > S654.5 Biofertilizers T Technology > TP Chemical technology > TP248 Nanogels. Nanoparticles. T Technology > TP Chemical technology > TP248.27.P55 Plant biotechnology. |
| Divisions: | Faculty of Industrial Technology > Material & Metallurgical Engineering > 28201-(S1) Undergraduate Thesis |
| Depositing User: | Arummitha Qurrotu 'aini |
| Date Deposited: | 26 Jan 2026 04:13 |
| Last Modified: | 26 Jan 2026 04:13 |
| URI: | http://repository.its.ac.id/id/eprint/130285 |
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