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: Elektrodeposisi Film Tipis Semikonduktor Cu2ZnSnS4 (CZTS) pada Substrat Kaca ITO
Abstrak: Semiconductor Cu2ZnSnS4 (CZTS) thin film that can be used as absorber layers on solar cell module was made via electrodeposition method. CZTS thin film was electrodeposited on the surface of a silicate glass coated with a thin layer of indium tin oxide (ITO). Deposition process was done using potentiostatic mode at room temperature with a potential of 1.05 V for 30, 45, and 60 minutes, followed with annealing the film at 2 different temperatures, 500 ºC using furnace and 180 ºC using hot plate, both treatments for 45 minutes in N2/H2S atmosphere. The X-ray difractograms were analyzed using Match 2 program and showed that the CZTS thin films had kesterit crystalline structure, with a low percentage of CZTS phase. The thin film also contained secondary phases such as Cu2S, ZnS, and SnS. The obtained CZTS thin films had a thickness between 1.039 and 1.676 μm. Absorption study showed that the band gap energy of CZTS thin films which was annealed using furnace ranged from 1.50 to 1.52 eV, whereas that annealed using the hot plate was not observed. The band gap energy value showed that CZTS thin films can be used as sunlight absorber layers on solar cell. The formation of CZTS crystal film on this investigation was effectively performed using furnace annealing process at a temperature of 500 ºC with deposition time of 45 minutes.
Keyword: Thin film, Electrodeposition, Cu2ZnSnS4