Judul: Effect of Different CO2 Sources on Microalgae-Microbial Fuel  Cell Design on Bioelectricity and Growth of Spirulina platensis
Abstrak: Microalgae-Microbial Fuel Cell (MMFC) merupakan integrasi kultur mikroalga dalam sistem MFC untuk menghasilkan energi listrik dari proses metabolisme mikroorganisme seperti bakteri elektrogenik. Penelitian ini bertujuan membandingkan elektrisitas, pertumbuhan S. platensis, dan karakteristik limbah cair pemindangan dari dua desain MMFC yang berbeda, yaitu desain MMFC dua chamber dengan selang aliran CO2 (MMFC-1) dan desain MMFC dua chamber dengan aerator (MMFC-2). Penelitian dilakukan dengan mengintegrasikan kultur S. platensis dengan campuran lumpur aktif dan limbah pemindangan pada perbandingan 1:10. Sumber CO2 yang berbeda memberikan pengaruh nyata terhadap elektrisitas, tetapi tidak berpengaruh nyata terhadap nilai OD dan biomassa kering S. platensis. Desain MMFC-2 memiliki elektrisitas lebih tinggi dibandingkan MMFC-1 dengan nilai tegangan 703,33 ± 38,21 mV, kuat arus 3,66 ± 0,36 mA, rapat daya 85,01 ± 6,29 mW/cm2, serta biomassa kering S.platensis lebih tinggi (0,17 ± 0,09 g/L). Kedua kondisi pada MMFC dapat menurunkan COD sampai 9,79%, BOD 31,12%, TAN 78,01% dan CO2 terlarut 67,69%., Microalgae-Microbial Fuel Cell (MMFC) is an integration of microalgae culture in the MFC system to produce electrical energy from the metabolic process of microorganisms such as electrogenic bacteria. This study aims to compare the electricity, growth of S. platensis, and characteristics of boiled fish processing wastewater from two different MMFC designs, namely the design of a two-chamber MMFC with a CO2 flow hose (MMFC-1) and a two-chamber MMFC design with an aerator (MMFC-2). The research had conducted by integrating the culture of S. platensis and a mixture of activated sludge and boiled fish processing wastewater in a ratio of 1:10. Different CO2 sources have a significant effect on electricity but have no significant effect on the OD value and dry biomass of S. platensis. The MMFC-2 design has a higher electrical than MMFC-1 with a voltage value of 703,33 ± 38,21 mV, a current of 3,66 ± 0,36 mA, a power density of 85,01 ± 6,29 mW/cm2, and biomass dry S. platensis was higher (0,17 ± 0,09 g/L). Both conditions in MMFC can reduce COD up to 9,79%, BOD 31,12%, TAN 78,01%, and dissolved CO2 67,69%.
Keyword: Limbah perikanan, Mikroalga, MMFC

Judul: Biolistrik pada Microalgae-Microbial Fuel Cell (MMFC) Menggunakan Limbah Cair Pemindangan dan Spirulina Platensis dengan Salinitas Berbeda
Abstrak: Microalgae-microbial fuel cell (MMFC) adalah sistem bioelektrokimia yang mengubah cahaya menjadi listrik berdasarkan reaksi biokatalitik dalam sel mikroba. Teknologi MMFC dapat memanfaatkan energi kultivasi Spirulina platensis dan limbah cair pemindangan menjadi energi listrik. Penelitian bertujuan menentukan kemampuan MMFC 2 bejana dalam menghasilkan bioelektrisitas, menentukan pengaruhnya terhadap perubahan COD, BOD, dan TAN dari limbah pemindangan dan menentukan pertumbuhan Spirulina platensis. Penelitian ini menggunakan kultur Spirulina dengan salinitas 15 ppt (MMFC-A) dan 0 ppt (MMFC-B). Nilai elektrisitas pada MMFC-A menghasilkan tegangan 233 ±17,99 mV, current density 138,004 ± 37,56 mA/m2 , dan power density 31,8 ± 9,00 mW/m2 lebih besar dibanding MMCF-B. Salinitas memengaruhi bioelektrisitas pada sistem MMFC. Pertumbuhan Spirulina pada MMFC-B menghasilkan biomassa kering sebesar 0,251±0,076 g/L. Nilai COD, BOD dan TAN menurun, sedangkan nilai pH meningkat. Sistem Microalgae-microbial fuel cell (MMFC) menunjukkan adanya potensi untuk dikembangkan di masa depan, baik dalam menghasilkan elektrisitas maupun biomassa., Microalgae-microbial fuel cell (MMFC) is a bioelectrochemical system that converts light into electricity based on biocatalytic reactions in microbial cells. MMFC technology can utilize the cultivation energy of Spirulina platensis and fishery wastewater into electrical energy. This study aimed to determine the ability of the MMFC dual-chamber to produce bioelectricity, determine the effect of changes in COD, BOD, and TAN from the fishery wastewater, and determine the growth of Spirulina platensis. This study used Spirulina culture with a salinity of 15 ppt (MMFC-A) and 0 ppt (MMFC-B). The electrical value of MMFC-A produces a voltage of 233 ±17,99 mV, a current density of 138,004 ± 37,56 mA/m2 , and a power density of 31,8 ± 9,00 W/m2 which is greater than MMCF-B. Salinity affects the bioelectricity of the MMFC system. Spirulina growth on MMFC-B produced dry biomass of 0.251±0.076 g/L. The COD, BOD, and TAN values decreased, while the pH values increased. This Microalgae-microbial fuel cell (MMFC) system shows the potential to be developed in the future, both in producing electricity and biomass.
Keyword: Fishery Wastewater, MMFC, Spirulina platensis

Judul: Truncated Stop Loss as a Optimal Solution of Reinsurance Agreement in One-Period Model
Abstrak: Reinsurance is one of risk management efforts of an insurance company, which is called the cedent. Similar with insurance, reinsurance constitutes the cedent to pay the premium. We consider one-period reinsurance model and derive a rule which minimizes the ruin probability of the cedent for a fixed reinsurance premium. Therefore, it is needed to construct an optimal reinsurance agreement for the cedent. The premium is calculated according to four different principles, i.e. economic, generalized zero-utility, Esscher, and mean-variance principles. Stop loss is a reinsurance contract which protect the insurance company for losses that exceed a certain amount. The result of this research shows that a truncated stop loss is an optimal agreement in the class of all reinsurance contracts with various premiums calculated using above mentioned principles.
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