Judul: Integration of Photosynthesis Microbial Fuel Cell using  Citrobacter freundii GBH253 and Chlorella sp ICBB9005 in Tofu Wastewater
Abstrak: Photosynthesis Microbial Fuel Cell (PMFC) integration covering wastewater treatment, electricity production, and microalgae biomass production has prospects to be applied. Electricity production can be increased by combining wastewater as substrate and sodium acetate as co-substrate to increase exoelectrogen microbial activity in transferring extracellular electrons. This study aims to optimize electricity production by combining tofu wastewater as a substrate with sodium acetate as a co-substrate in the growth medium for Citrobacter freundii GBH253 at the anode. Chlorella sp. ICBB9005 is an electron acceptor, utilizing tofu wastewater as a carbon source with photosynthesis at the cathode. The treatment is given in this study various concentrations of sodium acetate co-substrate (0, 10, 20, 30 mM) in tofu wastewater. The research design used was a completely randomized design with an analysis of variance and Tukey's test to determine the significance of the effect between treatments (p<0,05). The results showed that 30 mM sodium acetate co-substrate was added into tofu wastewater 40% (v/v) as a growth media for C.freundii GBH253 5% (v/v) was able to produce maximum output voltage and power density 785,5 mV and 273,43 mW.m-2 at the anode PMFC. Each treatment differs significantly (P<0.05). Chlorella sp. ICBB9005, as an electron acceptor, produced O2 utilizing tofu wastewater as a carbon source with photosynthesis and reduced COD at the cathode PMFC. Utilizing tofu wastewater while producing biomass of Chlorella sp. ICBB9005 is 0.748 g.mL-1 at the cathode PMFC. Based on this study's results, the PMFC uses C. freundii GBH253 and Chlorella sp. ICBB9005 has the integrated to reducing COD and optimizing bioelectricity and biomass microalgae.
Keyword: Citrobacter freundii GBH253, Chlorella sp, ICBB9005, Power Density, Biomass, Photosynthesis Microbial Fuel Cell

Judul: Bioelectricity Production from Citrobacter freundii GBH253 and Chlorella pyrenoidosa on Microbial Fuel Cell Anode with Different Carbon Sources
Abstrak: Microbial Fuel Cell (MFC) development has significantly increased from various aspects to get higher and more stable electricity. Developing MFC on microorganism aspect is very important because it plays a crucial role in the MFC system. C. freundii GBH253 is one of the potential exoelectrogen bacterium that could be developed for the MFC system. Integrating C. freundii GBH253 and electricity-producing microalgae, such as C. pyrenoidosa, in the anode of MFC could get more stable and higher electricity. In this study, C. freundii GBH253 and C. pyrenoidosa were coupled to produce electricity from different substrates. C. freundii GBH253 and C. pyrenoidosa were tested on three different media types before being tested on MFC. They were also examined for the co-cultivation test to determine the symbiotic relationship between the two microorganisms. The MFC test was conducted using the Randomized Block Design Factorial and the Tukey test to see significant differences from each treatment. The parameters observed in this study were voltage, power density, Chemical Oxygen Demand (COD), Coulombic Efficiency (CE), pH, and volatile fatty acid (VFA). C. freundii GBH253 cannot grow on microalgae medium, while C. pyrenoidosa could grow on bacterial medium and a mixture of bacterium and microalgae media. The bacterium gained benefit from co-culture with microalgae. In the MFC test, electricity was generated in all treatments, which bacterium + microalgae with acetate treatment could generate power density up to 211,97 mW/m2 and the most stable compared to others. Production of electricity in bacterium-microalgae combination dominated by the bacterium; hence, microalgae still help bacterium by producing electricity and raised the COD value. The pH value of all treatments was higher than the initial pH. Acetate and phenol were VFA produced in all treatments, whereas butyric acid and propionic acid were found in some treatments. Pearson correlation showed that some VFA highly correlated with power density.
Keyword: Chlorella pyrenoidosa, Substrate, Microbial Fuel Cell, Electricity Producing Microalgae, Volatile Fatty Acid, Citrobacter freundii

Judul: Karakteristik Barisan Eksak Pendek HomR(N, ) dan HomR( ,N)
Abstrak: Module merupakan generaIisasi dari ruang ve}ctor, dimana pada ruang vektor skalar-skalamya berasal dati suatu lapangan (field) sedangkan pada module skaJar-skalamya merupalam unsur-unsur dan suatu ring R dengan unsur satuan. Dari suatu grup komutatif yang unsur-unsumya dipadukan dengan unsur-unsur dart suatu ring R, maka akan mengbastlk.an yang namanya R-module. Himpunan seroua fungsi homomorfisma yang memetakan dati R-module M ke R-module N dinotasikan sebagai HomiM,N), dimana HomiM,N) juga merupakan suatu R-module.
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