Judul: Diastase Enzyme Activity and Antibacterial Effectiveness to Gastroenteritis by Apis mellifera Honey from Indonesia
Abstrak: Kualitas madu monoflora (Apis mellifera) sebagai antibakteri dapat dipengaruhi oleh aktivitas enzim diastase dan metabolit sekunder sumber nektar. Penelitian ini bertujuan untuk membandingkan aktivitas enzim diastase dan efektivitas madu monoflora yang berasal dari lebah Apis mellifera sebagai antibakteri alami terhadap bakteri Staphylococcus aureus, Escherichia coli, dan Salmonella typhi. Metode pengambilan sampel madu monoflora dari sembilan sumber nektar yang berbeda (akasia, kaliandra, rambutan, kayu putih, randu, mangga, kopi robusta 1, kopi robusta 2, dan karet) dilakukan dengan menentukan nilai diastase menggunakan spektrofotometri UV-Vis dan zona hambat bakteri menggunakan cakram difusi. Analisis multivariatif kadar brix, aktivitas enzim diastase, dan antibakteri menggunakan Principal Component Analysis (PCA). Hasil penelitian menunjukkan bahwa aktivitas enzim diastase tertinggi sebesar 20,00 DN pada madu mangga, rambutan, dan kopi robusta 2, sedangkan terendah sebesar 4,00 DN pada madu kaliandra. Aktivitas antibakteri terhadap S. aureus tertinggi sebesar 19,47 mm pada madu kopi robusta 2, terhadap E. coli sebesar 27,93 mm pada madu randu, dan terhadap S. typhi sebesar 18,53 mm pada madu kopi robusta 2. Nilai konsentrasi hambat minimum (KHM) tehadap bakteri yang diuji sebesar 8 µg/mL pada madu akasia, kayu putih, randu, kopi robsuta 1, dan kopi robusta 2. Analisis klasterisasi berdasarkan kadar brix, aktivitas enzim diastase, dan antibakteri yaitu klaster 1 (kaliandra); klaster 2 (akasia, kayu putih, randu, kopi robusta 1); klaster 3 (mangga, rambutan, kopi robusta 2); klaster 4 (karet)., The quality of monoflora honey (Apis mellifera) as an antibacterial can be influenced by the activity of the diastase enzyme and the secondary metabolites of the nectar source. This study aims to compare the activity of the diastase enzyme and the effectiveness of monoflora honey derived from Apis mellifera bees as a natural antibacterial agent against Staphylococcus aureus, Escherichia coli, and Salmonella typhi. The sampling method for monoflora honey from nine different nectar sources (acacia, calliandra, rambutan, eucalyptus, randu, mango, robusta coffee 1, robusta coffee 2, and rubber) was carried out by determining the diastase value using UV-Vis spectrophotometry and the bacterial inhibition zone using the diffusion disc. Multivariate analysis of brix content, diastase enzyme and antibacterial activity using Principal Component Analysis (PCA). The results showed that the highest diastase enzyme activity was 20.00 DN in mango, rambutan, and robusta coffee 2 honeys, while the lowest was 4.00 DN in calliandra honey. The highest antibacterial activity against S. aureus was 19.47 mm in robusta coffee 2 honey, against E. coli was 27.93 mm in randu honey, and against S. typhi was 18.53 mm in robusta coffee 2 honey. Minimum inhibitory concentration (MIC) values for the tested bacteria were 8 g/mL on acacia honey, eucalyptus, randu, robsuta coffee 1, and robsuta coffee 2. Clusterization analysis was based on brix content, diastase enzyme activity, and antibacterial activity, namely cluster 1 (calliandra); cluster 2 (acacia, eucalyptus, randu, robusta coffee 1); cluster 3 (mango, rambutan, robusta coffee 2); and cluster 4 (rubber).
Keyword: antibakteri, enzim diastase, madu Apis mellifera, antibacterial, diastase enzyme, Apis mellifera honey

Judul: Uji Efektivitas Madu dari Empat Spesies Lebah Berbeda sebagai Agen Antibakteri.
Abstrak: Banyak penyakit yang diakibatkan oleh bakteri. Pengobatan infeksi dapat dilakukan dengan memberikan antibakteri pada luka. Salah satu antibakteri alami adalah madu. Tujuan dari penelitian ini adalah menganalisis efektivitas madu sebagai agen antibakteri. Bakteri target yang digunakan adalah Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538 dan Pseudomonas aeruginosa ATCC 15442. Uji antibakteri terdiri dari 4 tahap yaitu uji disk, uji viabilitas, uji pH dan uji proksimat. Hasil uji antimikroba menunjukkan bahwa madu TG1_PND yang berasal dari Stingless Bee memiliki aktivitas antibakteri tertinggi dibanding madu lainnya. Hasil uji viabilitas menunjukkan ketiga bakteri mengalami penghambatan pertumbuhan terbaik dalam konsentrasi madu 100%. Adapun kandungan pH madu diuji melalui pengukuran menggunakan pH meter dan diketahui bahwa madu dengan kode TG1_PND memiliki pH terendah yaitu 2,7. Kandungan air pada madu dapat memengaruhi kualitas madu dan pertumbuhan mikroba., Many diseases are caused by bacteria. Treatment of infection can be done by giving antibacterial to the wound. One natural antibacterial is honey.The purpose of this study was to analyze the potential of honey as an antibacterial. The target bacteria used were Escherichia coli ATCC 8739, Staphylococcus aureus ATCC 6538 and Pseudomonas aeruginosa ATCC 15442. The test consisted of 4 stages, namely disk test, viability test, pH test and proximate test. The antibacterial test results showed that TG1_PND honey from Stingless Bee had the highest antibacterial activity compared to other honeys. The results of the viability test showed that the three bacteria experienced the best growth inhibition in 100% honey concentration. The pH content of honey was tested by measuring using a pH meter and it was found that honey with the code TG1_PND had the lowest pH of 2.7. Water content in honey can affect honey quality and microbial growth.
Keyword: Antibakteri, Bakteri, Madu, Penghambatan, antibacterial, bacteria, honey, inhibition

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