Judul: Identification of Bacterial Community in Vannamei Shrimp (Litopenaeus vannamei) from Two Different Market Locations Using Metagenomic Technology
Abstrak: Udang merupakan komoditas hasil perairan yang mudah mengalami proses kemunduran mutu, salah satunya disebabkan oleh aktivitas bakteri. Penggunaan media kultur dalam proses identifikasi komunitas bakteri menjadi kurang optimal, karena proses kultivasi tidak dapat menumbuhkan semua jenis bakteri. Penelitian ini bertujuan untuk mengidentifikasi komunitas bakteri yang terdapat pada komoditas udang segar dengan teknik metagenomik. Proses identifikasi bakteri dilakukan melalui tahap pengusapan permukaan udang, kemudian isolasi DNA bakteri menggunakan Wizard Genomic DNA Purification Kit dan amplifikasi menggunakan primer universal 16S rRNA dengan wilayah V3-V4. Proses sekuensing dilakukan menggunakan teknik Next Generation Sequencing. Komunitas bakteri yang teridentifikasi didominasi oleh filum Bacteroidota, Patescibacteria, Firmicutes, Fusobacteriota, Campilobacteriota, Actinobacteriota, dan Proteobacteria. Potensi kelompok bakteri patogen dan pembusuk pada udang teridentifikasi berasal dari genus Myroides, Flavobacterium, Pseudomonas, Aeromonas, Escherichia, Shigella dan Shewanella, Shrimp is an aquatic product that is prone to deterioration in quality, one of which is caused by bacterial activity. The use of culture media in the identification process of bacterial communities is less than optimal because the cultivation process cannot grow all types of bacteria. This study aims to identify the bacterial community found in fresh shrimp commodities with a metagenomic approach. The bacterial identification process was carried out by swabbing the surface of the shrimp, then isolating bacterial DNA using the Wizard Genomic DNA Purification Kit and amplification using a universal 16S rRNA primer with a V3-V4 region. The sequencing process was carried out using Next Generation Sequencing. The identified bacterial community was dominated by the phyla Bacteroidota, Patescibacteria, Firmicutes, Fusobacteriota, Campilobacteriota, Actinobacteriota, and Proteobacteria. Potential groups of pathogenic and spoilage bacteria in shrimp were identified from the genera Myroides, Flavobacterium, Pseudomonas, Aeromonas, Escherichia, Shigella, and Shewanella
Keyword: amplicon sequence variants, bakteri, DNA, udang

Judul: Identification of Bacterial Communities in Eastern Little Tuna (Euthynnus affinis) from Traditional and Modern Market Locations with Metagenomic Analysis
Abstrak: Penanganan pasca panen dengan penerapan rantai dingin dan higiene yang baik merupakan tahapan penting untuk dapat menjaga kualitas ikan dan keamanan pangan. Perbedaan tingkat higiene yang diterapkan pada pasar tradisional dan modern akan mempengaruhi komunitas bakteri pada ikan tongkol. Penelitian ini bertujuan mengisolasi DNA bakteri dan mengidentifikasi komunitas bakteri dengan analisis metagenomik. Tahapan penelitian terdiri dari pengumpulan sampel, inkubasi bakteri, isolasi DNA bakteri dengan kit komersial, permurnian isolat DNA, Next Generation Sequencing dengan target gen 16S rRNA wilayah variabel V3-V4, dan analisis data dengan program bioinformatika. Kelimpahan sekuens bakteri pada ikan tongkol yang berasal dari pasar tradisional sebanyak 42.829 sekuen sedangkan dari pasar modern sebanyak 30.989 sekuen. Filum bakteri yang mendominasi pada kedua sampel tersebut yaitu Fusobakteriota, Bakteroidota, dan Patescibakteria. Komunitas bakteri pada ikan tongkol pasar tradisional memiliki kelimpahan relatif tertinggi pada genus Myroides (42,3%) sedangkan dari pasar modern pada genus Cetobacterium (80,2%)., Post-harvest handling, which includes the use of cold chain and proper hygiene, is a critical in maintaining fish quality and food safety. The bacterial community in eastern little tuna will be affected by differences in the level of hygiene used in traditional and modern markets. This study aims to isolate bacterial DNA and identify bacterial communities by metagenomic analysis. The research stages consisted of sample collection, bacterial incubation, isolation of bacterial DNA with commercial kits, purification of DNA isolates, NGS with the target gene for 16S rRNA V3-V4 variable region, and data analysis using bioinformatics programs. The sequence abundance of bacteria in eastern little tuna from traditional markets was 42.829 sequences while those from modern markets were 30.989 sequences. Fusobakteriota, Bacteroidota, and Patescibakteria were the most predominant bacterial phyla in both samples. Traditional market eastern little tuna had the highest relative abundance in the genus Myroides (42,3%), while the modern had the highest relative abundance in the genus Cetobacterium (80,2%).
Keyword: 16S rRNA, Next Generation Sequencing, Bacterial communities, Eastern Little Tuna, Hygiene

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