Kinerja Microbial Fuel Cell dalam Menghasilkan Bioenergi menggunakan Membrane Electrode Assembly (MAE) dengan Bantuan Bakteri Bacillus subtilis dan Eschericia coli

Abstract

Pasokan bahan bakar fosil semakin menipis sementara kebutuhan energi Indonesia terus menerus meningkat secara signifikan sehingga diperlukan upaya pengembangan energi terbarukan. Microbial fuel cell (MFC) merupakan teknologi yang menghasilkan listrik melalui aktivitas metabolisme mikroba elektrokimia, dengan cara mengoksidasi senyawa organik, sekaligus berpotensi mengolah limbah organik. Penggunaan konsosium Bacillus subtilis dan Escherichia coli dalam sistem MFC dinilai mampu meningkatkan efisiensi transfer elektron karena keduanya memiliki transfer elektron yang saling melengkapi. Faktor lingkungan seperti pH dan ketersediaan substrat (glukosa) sangat memengaruhi efisiensi sistem. Perpindahan proton akan didukung dengan modifikasi Membrane Electrode Assembly (MEA). Penelitian ini menggunakan substrat berupa limbah organik yang ditambahkan konsorsium B. subtilis dan E. coli. Variasi pH (2,4,7) dan konsentrasi glukosa (10%, 20%, 30%) digunakan untuk mengevaluasi pengaruh lingkungan terhadap performa MFC. Konsorsium dibuat dengan cara menginokulasi kultur murni kedua bakteri dan diinkubasi agar pertumbuhan optimal. Pembuatan MEA dilakukan dengan menggunakan teknik hot pressing menggunakan kertas karbon dan katalis Pt/C pada membran nafion. Pengukurangan arus, tegangan, dan power density dilakukan menggunakan multimeter setiap jam selama 30 jam, sedangkan analisis TPC dan OD dilakukan untuk mengukur kepadatan bakteri. Hasil menunjukkan konsorsium B. subtilis dan E. coli tumbuh baik, dengan nilai TPC sebesar 1,86 × 108 CFU/ml dan 1,91×108 CFU/ml. Nilai OD600 yang meningkat hingga fase stationer pada jam ke-24 yang menunjukkan kondisi lingkungan mendukung pertumbuhan aktif bakteri. Modifikasi MEA yang terbentuk memiliki pori rapat dan seragam. Hal ini dapat meningkatkan proses transfer elektron dan proton pada sistem MFC, meskipun terjadi degradasi selama operasi akibat pembentukan biofilm dan fluktuasi pH. Kinerja terbaik sistem MFC dicapai pada pH 7 dan konsentrasi glukosa 30% dengan menghasilkan arus sebesar 6,988 mA, tegangan 8,592 V, dan power density 1000,68 mW/m2 menunjukkan kinerja bioelektrik yang tinggi sehingga dapat dijadikan alternatif teknologi energi yang ramah lingkungan dan berkelanjutan

Fossil fuel supplies are no longer available while Indonesia's energy needs continue to increase significantly, so renewable energy development efforts are needed. Microbial Fuel Cell (MFC) is a technology that produces electricity through electrochemical microbial metabolic activity, by oxidizing organic compounds, as well as the potential to process organic waste. The use of Bacillus subtilis and Escherichia coli consortium in the MFC system is considered to be able to increase the efficiency of electron transfer because both have complementary electron transfer. Environmental factors such as pH and substrate availability (glucose) greatly affect the efficiency of the system, while the presence of biofilm supports the stability and efficiency of electron transfer. Proton transfer will be supported by modification of the Membrane Electrode Assembly (MEA). The method uses a substrate in the form of organic waste added with B. subtilis and E. coli consortium. Variations in pH (2,4,7) and glucose concentration (10%, 20%, 30%) were used to evaluate the effect of environment on MFC performance. The consortium was made by inoculating pure cultures of both bacteria and incubated for optimal growth. Preparation of MEA was done by using hot pressing technique using carbon paper and Pt/C catalyst on nafion membrane. Current, voltage, and power density were measured using a multimeter every hour for 30 hours, while TPC and OD analysis were conducted to measure bacterial density. The results showed that the consortium of B. subtilis and E. coli grew well, with TPC values of 1,86 × 108 CFU/mL and 1,91 × 108 CFU/mL. The OD600 value increased until the stationary phase at the 24th hour, indicating that the environmental conditions support the active growth of bacteria. MEA modification succeeded in forming a tight and homogeneous membrane structure, increasing the efficiency of electron and proton transfer in the MFC system, although degradation occurred during operation due to biofilm formation and pH fluctuations. The best performance of the MFC system was achieved at pH 7 and 30% glucose concentration by producing a current of 6.988 mA, a voltage of 8.592 V, and a power density of 1000.68 mW/m2 indicating high bioelectric performance so that it can be used as an alternative energy technology that is environmentally friendly and sustainable.