Biosurfactant is environmentally friendly surfactant produced by a certain microorganism in a lipid-rich medium. A previous study has shown that Halomonas meridiana BK-AB4 had the potential of a moderately halophilic bacterium in converting olive oil into biosurfactant. In the present study, the effect of changing the carbon source from olive oil into cheaper and more abundant vegetable oil, which is palm oil, for the production of the biosurfactant was evaluated. The study began by optimizing the production medium with varying the nitrogen source, the concentration of palm oil and pH. The optimum condition of biosurfactant production was observed in the medium consisted of 0.6% (w/v) of urea, 2% (v/v) of palm oil and pH 9. The resulted biosurfactant was stable at pH 7-10 and in the salt concentration of 6-15%. Biosurfactant activity in lowering air-water surface tension was measured using the Du Noüy ring method, and the value of critical micelle concentration (CMC) was about 233 ppm. At this point, the surface tension of water dropped from 68.3 to 49.8 dyne/cm. Preliminary structural analysis by using FTIR technique suggested that the resulted biosurfactant has -OH, -C-H aliphatic C=C, H-C-C and C=O groups in its structure, which is similar to that of the fatty-acid type of biosurfactant. The potential of biosurfactant as a metal corrosion inhibitor was evaluated by using electrochemical impedance spectroscopy (EIS) that measured at 30 °C. The measurement revealed that the highest inhibition level was observed at the biosurfactant concentration about 200 ppm that corresponds to the inhibition level about 53.23%. ABSTRAKBiosurfaktan adalah surfaktan ramah lingkungan yang diproduksi oleh mikroorganisme tertentu dalam media kaya lemak. Dalam studi sebelumnya, telah ditemukan potensi bakteri halofilik, Halomonas meridiana BK-AB4, dalam mengkonversi minyak zaitun ke biosurfaktan. Dalam penelitian ini dipelajari efek variasi sumber karbon dari minyak zaitun ke minyak yang lebih murah dan berlimpah, yaitu minyak sawit, untuk produksi biosurfaktan. Studi ini dimulai dengan mengoptimalkan produksi media pada berbagai sumber nitrogen, konsentrasi minyak sawit dan pH. Kondisi optimum produksi biosurfaktan diamati dalam medium yang terdiri dari 0,6% (b/v) urea, 2% (v/v) minyak sawit dan pH 9. Produksi biosurfaktan stabil pada pH 7-10 dan konsentrasi garam 6-15%. Aktifitas biosurfaktan dalam menurunkan tegangan permukaan air-air diukur menggunakan metode cincin Du Noüy, nilai konsentrasi Misel kritis (CMC) adalah sekitar 233 ppm. Pada titik ini, tegangan permukaan air menurun dari 68,3 ke 49.8 dyne/cm. Analisis awal struktur menggunakan teknik FTIR dihasilkan bahwa biosurfaktan memiliki gugus -OH, -C-H alifatik C=C, H-C-C dan C=O dalam strukturnya, yang mirip dengan jenis asam lemak biosurfaktan. Potensi biosurfaktan sebagai inhibitor korosi logam dievaluasi menggunakan spektroskopi impedansi elektrokimia (EIS) yang diukur di 30 °C. Pengukuran menunjukkan bahwa tingkat inhibisi diamati pada konsentrasi biosurfaktan sekitar ...

Borax is a chemical substance that is prohibited from being used as a food additive because of its toxic nature. However, the use of borax is still widely found, one of which is meatballs the most. This study aims to identify the borax content in meatballs. Samples were taken from Ciroyom Market, Bandung City, Indonesia using total sampling and obtained as many as 10 samples of meatballs. The samples were analyzed qualitatively by observing physical conditions and testing using BaCl2 solution. Meanwhile, quantitative analysis was carried out using a UV-Vis spectrophotometer at a wavelength of 428 nm. The results of the analysis showed that all samples were indicated to contain borax. Even the quantitative test using UV-Vis spectrophotometer showed that the highest borax content was found in sample 10, which was 3.672,9 µg/ml.

Rhodamine B is a synthetic dye that is often misused as a food coloring in crackers. Rhodamine B consumption through food can irritate the digestive tract, impair liver function, and cancer. The purpose of the study was to determine the content of rhodamine B in crackers. This study used a quantitative method, and purposive sampling was employed as a sampling technique. Method validation was carried out against a UV-Visible spectrophotometer in testing Rhodamine B in crackers. Validation of the method produces a linear regression equation of y = 0.2901x + 0.0082, with a correlation coefficient value (r2) = 0.9985, and a Vxo value of 2.65%. The instrument validation shows a Limit of Detection (LOD) of 0.1582 ppm and a Limit of Quantification (LOQ) of 0.5274 ppm. The results from the accuracy-test showed an average %diff of 0.88%; 3.79%, and -6.88%, while the average percentages of recovery were 101%, 104, and 93% respectively. Precision testing results showed that the value of % RSD 2/3 CV Horwitz. Qualitative measurements showed that all samples tested for Rhodamine B in this study showed negative results. This study suggested that UV-Visible spectrophotometry is a valid method that can be used to measure levels of Rhodamine B in food.

Latar belakang: Air merupakan sumber kehidupan bagi manusia, hewan dan biota lainnya. Kerusakan sungai Citarum sudah mengkhawatirkan. Hal ini mendorong pemerintah untuk bersinergi menyelaikan masalah pencemaran lingkungan di sungai Citarum melalui program Citarum Harum yang diharapkan dapat bersinergi dengan Perguruan Tinggi. Penelitian ini salah satu bentuk upaya partisipasi aktif dosen untuk ikut mensukseskan program pemerintah tersebut. Kromium heksavalen terdapat dalam air sungai Citarum, ini telah dapat dihilangkan dengan metode biosorpsi. Biosorpsi menggunakan adsorben biologis merupakan metode alternatif untuk dapat membersihkan logam berat dalam air sungai Citarum. Pemanfaatan Saccharomyses cerevisiae dan Rhizopus orizae sebagai biomaterial yang mampu menyerap logam berat.Tujuan Penelitian: Penelitian ini bertujuan untuk mengetahui penurunan logam berat setelah dilakukan proses adsorpsi logam berat Cr6+ dalam air sungai Citarum oleh biomassa S.cerevisiae dan R. orizae.Metode Penelitian: Metode yang digunakan pada penelitian ini yaitu melakukan uji Biosorpsi menggunakan Saccharomyses cerevisiae dan Rhizopus orizae skala Laboratorium. Jumlah S. cerevisiae yang diujikan pada penelitian ini adalah 250 μ, 500 μ dan 750 μ karena jamur yang digunakan dalam bentuk suspensi. Jumlah Rhizopus orizae yang digunakan adalah sebanyak 0,1 sampai dengan 2 g bentuk jamur ini berupa residu kering yang dihiangkan airnya melalui metode pemanasan open. Pemutaran biosorpsi menggunakan S.cerevisae diujikan dengan 250 rpm, 750 rpm dan 1500 rpm. Sedangkan untuk biosorpsi menggunakan R.orizae diujikan dengan kecepatan pengadukan 750 rpm. Kadar logam Cr6+ ditentukan melalui pengukuran dengan menggunakan instrumentasi Spektrofotometer UV-Vis panjang gelombang 525 nm.Hasil: Berdasarkan hasil pengujian tersebut memberikan kesimpulan bahwa S. cerevisiae dan Rhizopus orizae dapat menyerap logam Cr6+ dalam air sungai citarum dengan efektif. Penurunan tertinggi diperoleh pada penambahan adsorben terbanyak yaitu 750 μ untuk S. cerevisiae dan 1,6 g untuk R. orizae.Simpulan: Biomassa S. cerevisiae dan Rhizopus orizae dapat menurunkan kadar logam Cr6+ dalam air sungai dengan kecepatan pengadukan optimum yaitu 1500 rpm dan kosentrasi biomassa 750 μ untuk S. cerevisiae dan 1,6 g untuk R. orizae.

The spread of COVID-19 in various countries has increased the death toll due to COVID-19. Spike glycoproteins of the SARS-CoV-2 virus have an important role in binding to host cell receptors. This spike can identify the SARS-CoV-2 kinship in Wuhan and other countries by phylogenetic analysis. This study aims to determine the phylogenetic relationship of COVID-19 from Wuhan with the other countries obtained from the NCBI Gene bank based on spike chain A glycoproteins. The method uses NCBI's BLAST program to search for similar sequences, ClustalW's program to perform multiple alignment sequencing, and MegaX to create a phylogenetic tree. The research results Spike glycoprotein chain A in Wuhan has the closest kinship with the United States. This is indicated by the formation of tree branches close to each other but still in the same group as spike glycoproteins in other countries. Phylogenetic tree validated by the bootstrap test that value of 100%, which means it shows the sturdiness of the tree can be trusted. The conclusion is there is no significant difference in the characteristics of spike glycoprotein chain A, as for some countries that have spike amino acid differences in glycoprotein chain A, such as Pakistan, Poland, and Wuhan. The amino acid difference is considered normal because the virus will continue to evolve in order to adapt to the environment