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: Bioelectricity Microalgae-Microbial Fuel Cell (MMFC) Using Different Bacterial Sources
Abstrak: Microalgae-Microbial Fuel Cell (MMFC) merupakan teknologi yang mengintegrasikan fotosintesis pada mikroalga untuk menghasilkan biomassa mikroalga dan memanfaatkan mikroba untuk mengubah senyawa organik air limbah menjadi energi listrik sehingga dapat mengolah air limbah secara bersamaan dan menghasilkan bioenergi. Penelitian bertujuan membandingkan bioelektrisitas, mendapatkan kurva pertumbuhan Spirulina sp. dan menentukan perubahan kualitas limbah cair pemindangan awal dan akhir. Penelitian ini menggunakan penambahan bakteri Bacillus subtilis (MMFC-1) dan lumpur aktif (MMFC-2), yang dapat menguraikan bahan organik pada limbah pemindangan. Perbedaan sumber bakteri yang berasal dari lumpur aktif dan bakteri Bacillus subtilis dalam sistem MMFC memengaruhi tingkat elektrisitas yang dihasilkan. Sistem MMFC-2 menghasilkan nilai tegangan maksimum dan power density yang lebih tinggi dibandingkan MMFC-1 yaitu 812 mV dan 107,878 mW/cm2. Pertumbuhan Spirulina sp. pada ruang katoda menghasilkan biomassa hingga 0,279 ± 0,001 g/L. Microalgae-microbial Fuel Cell pada kedua sistem dapat menurunkan beban polutan pada nilai COD, BOD, dan TAN yang menunjukkan penurunan dari sebelum pengoperasian MMFC. Teknologi microalgae-microbial fuel cell memiliki potensi untuk dikembangkan, tidak hanya dapat menghasilkan energi listrik dan biomassa Spirulina sp. yang memiliki nilai tambah tetapi dapat mengolah limbah cair perikanan secara bersamaan., Microalgae-Microbial Fuel Cell (MMFC) is a technology that integrates microalgae to produce microalgae biomass and microbes to convert wastewater organic compounds into electrical energy, so that it can simultaneously treat wastewater and produce bioenergy. The study compared the effectiveness of electrical energy, determining the growth curve of Spirulina sp. and determining changes in the quality of initial and final fish-boiled wastewater. This study used the addition of Bacillus subtilis (MMFC-1) bacteria and activated sludge (MMFC-2), which can decompose organic matter on fish-boiled wastewater. The difference in the source of bacteria from activated sludge and Bacillus subtilis bacteria in the MMFC system affects the level of electricity generated. The MMFC-2 system produces a higher maximum voltage and power density than the MMFC-1, which is 812 mV and 107.878 mW/cm2. The growth of Spirulina sp. in the cathode chamber produced biomass until 0.279 ± 0.001 g/L. Microalgae-microbial Fuel Cell in both systems can reduce the pollutant load in COD, BOD, and TAN values which show a decrease before the operation of the MMFC. Microalgae-microbial fuel cell technology has great potential to be developed, not only to produce electrical energy and Spirulina sp. which has added value but can treat fishery wastewater at the same time.
Keyword: activated sludge, Bacillus subtilis, liquid waste, MMFC, Spirulina sp.

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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