Judul: Analisis Keragaman Genetik Bakteri dalam Teknologi Budidaya Bioflok dengan Teknik ARDRA gen 16S-rRNA
Abstrak: A new approach to reducing farmed waste is aquaculture with biofloc technology (BFT-Bio-flocs technology). Bacteria is the main constituent in aquaculture systems with biofloc. This study aimed to analyze the genetic diversity of bacteria biofloc using 16S-rRNA PCR with ARDRA technique. A total of 38 dominant bacterial isolates was obtained and of these isolates, 16S-rRNA gene was then isolated and amplified using PCR. The 16S-rRNA gene of the isolates was then cut using HaeIII (5’-GG•CC) and HhaI (5’-GCG•C) restriction enzymes resulting an ARDRA pattern which was further used as the binary data for the construction of phylogenetics tree that can be used to estimate the group of bacteria. The result with HaeIII cutting restriction enzyme from bacteria bioflocs obtained 11 ARDRA patterns, while with the restriction enzyme HhaI obtained 8 ARDRA patterns. Phylogenetics of bacterial populations on tree water biofloc cultivation system consisting of at least 13 different bacterial species. Result of sequencing from 2 gene sample 16S-rRNA identified Microbacterium foliurum, and Pseudomonas putida.
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Judul: Genetic Diversity of Antifungal-Producing Rhizobacteria of Bacillus sp. Based on Amplified rDNA Restriction Analysis (ARDRA) and 16S rRNA Sequence
Abstrak: Genus Bacillus has indirectly mechanism to induce the growth of soybean plant by growth suppression of pathogen through production of antibiotic. The objective of this research was to analyze the diversity of 22 antifungal-producing rhizobacteria of Bacillus sp. strain Cr isolated from rhizosphere of soybean plant based on 16S rRNA Sequence and Amplified rDNA Restriction Analysis (ARDRA). ARDRA was a tool to measure and analyze the diversity of 22 isolates through digestion of 16S rRNA gene by restriction enzymes i.e. HinfI, HaeIII, and RsaI. Based on this analysis, genetic diversity of 22 Bacillus Cr isolates were classified into eight different groups by ARDRA analysis. Moreover, six isolates selected randomly from each ARDRA group that have strong activity to suppress fungal growth were compared with reference strains based on 16S rRNA partial sequence. The distributions of 22 isolates were genetically diverse on several species of Bacillus sp. such as B. subtilis, B. cereus, and B. fusiformis. Therefore, ARDRA is a reliable technique to analyze genetic diversity of huge bacterial community.
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Judul: Pembuatan Film Tipis Cu2ZnSnS4 sebagai Lapisan Penyerap Cahaya pada Sel Surya Menggunakan Metode Elektrodeposisi
Abstrak: Thin film of Cu2ZnSnS4 (CZTS) is an alternative semiconductor used as light absorber layer on solar cell. CZTS can replace silicon that commonly used as commercial semiconductor. The advantage of using CZTS as absorber layer is due to the abundance of its chemical composer on earth, and its high value of absorption coefficient. The absorber layer was made by using electrodeposition method on ITO glass substrates. The films were deposited at room temperature using potentiostatic mode with a potential of –1.05 V for 30, 45, and 60 minutes. After that, the films were annealed at two different temperatures, 180 ºC and 500 °C, for 45 minutes in N2/H2S atmosphere. Based on X-ray diffraction analysis, the polycrystalline thin film obtained fall into kesterite crystal phase. This type of crystal was obtained when the CZTS was annealed at 500 °C in H2S/N2 atmosphere. The value of optical band gap energy for the CZTS thin film was 2.2 eV with the film thickness about 1.228–6.366 μm. The sample of CZTS with electrodeposition time of 45 minutes and annealing temperature of 500 °C showed the best result and in conformity with absorber layers criteria for solar cells.
Keyword: semiconductor, ITO glass, CZTS thin film, electrodeposition