Curcumin has been known and used in the medical and industrial world. One way to improve its stability, bioavailability and its medical applications is using encapsulation method. In this research, we studied cocoliposome (coconut liposome) as the encapsulation material. The encapsulation efficiency (EE), loading capacity (LC), release rate (RR), as well as the free radical scavenging activity, measured by inhibition ratio (IR), of curcumin in encapsulation product were studied on varying cholesterol compositions and in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.4) conditions. We found that curcumin encapsulation in cocoliposome (CCL) formulation was influenced by cholesterol composition and pH conditions. The EE, LC and free radical scavenging activity diminished under both the SIF and SGF conditions when the cholesterol concentration enhanced. However, the RR increased as the cholesterol intensified. The condition to acquire the most favorable encapsulation parameter values was at 10% cholesterol composition. Furthermore, the IR results at 10% cholesterol concentration of CCL was 67.70 and 82.13% in SGF and SIF milieu, respectively. The CCL formulation thrived better under SIF conditions for free radical scavenging activities.

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Research on synthesis of bismuth oxide (Bi2O3) using sol-gel method with varying calcination temperatures at 500, 600, and 700 °C has been done. This study aims to determine the effect of calcination temperature on the characteristics of the obtained products which encompasses crystal structure, surface morphology, band-gap energy, and photocatalytic activity for the decolorization of methyl orange dyes through its kinetic study. Bismuth oxide prepared by sol-gel method was undertaken by dissolving Bi(NO3)3·5H2O and citric acid in HNO3. The mixture was stirred then heated at 100 °C. The gel formed was dried in the oven and then calcined at 500, 600, and 700 °C for 5 h. The obtained products were a pale yellow powder, indicating the formation of bismuth oxide. This is confirmed by the existence of Bi–O and Bi–O–Bi functional groups through FTIR analysis. All three products possess the same mixed crystal structures of α-Bi2O3 (monoclinic) and γ-Bi2O3 (body center cubic), but their morphologies and band gap values are different. The higher the calcination temperature, the larger the particle size and the smaller the band gap value. The accumulative differences in characteristics appoint SG700 to have the highest photocatalytic activity compared to SG600 and SG500 as indicated by its percent degradation value and decolorization rate constant.

Microbial Fuel Cell (MFC) adalah sistem bioelektrokimia yang mengubah energi kimia menjadi energi listrik yang melibatkan reaksi reduksi dan oksidasi dengan memanfaatkan mikroba. Tujuan penelitian ini adalah menentukan beda potensial yang dihasilkan sistem MFC pada substrat whey tahu menggunakan mikroba Lactobacillus bulgaricus dengan variasi bahan buffer fosfat dan pH. Penelitian ini menggunakan sistem MFC dual chamber dengan jembatan garam sebagai penghantar proton dari kompartemen anoda ke kompartemen katoda. Kompartemen anoda berisi campuran mikroba yang sudah dikultivasi dan buffer kalium fosfat atau buffer natrium fosfat dengan variasi pH, yaitu 5,5; 6; 6,5; 7. Pada katoda berisi elektrolit KMnO4 0,2 M, buffer fosfat, dan pH dengan variasi yang sama. Pengukuran beda potensial dilakukan pada suhu ruang selama 30 jam. Pengukuran kelistrikan pada sistem MFC menggunakan buffer kalium fosfat pada empat pH berbeda yaitu 7 ; 6,5 ; 6 ; 5,5 dalam 100 mL volume sistem masing-masing menghasilkan beda potensial yaitu sebesar 42,2 mV; 32 mV; 30 mV; 29,3 mV. Sedangkan dalam sistem buffer natrium fosfat dan 100 mL dengan variasi pH yang sama berturut-turut adalah 20 mV ; 18,6 mV ; 17 mV ; 4 mV. Buffer kalium fosfat menghasilkan beda potensial yang lebih besar dibandingkan dengan buffer natrium fosfat.

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