Microbial fuel cell (MFC) is one of promising fuel cell technologies. MFC utilizes biochemical activity of microorganism to convert the substrate to produce electricity through metabolism processes. Although the generation of the electricity is still in mW scale, MFCs has a great potential for the future application. The aim of this study was to investigate the performance of MFCs with and without the methylene blue (MB) as an electron mediator utilizing Saccharomyces cerevisiae as biocatalysts and glucose as substrate to generate electricity. Methods performed comprise of the S. cerevisiae yeast culture rejuvenation, preparation of the inoculum, preparation of the MFC reactor, preparation of MFC medium with 2% of glucose with and without MB mediator, periodical sampling, determination of growth curve, measurement of current, potential, calculation of power density, energy, glucose consumption, and production of bioethanol. MFC with mediator generated 5.5×10-5A of current, 0.886V of potential, 4.48×10-3 W/m2 of power density, 4.14×10-3 J of energy, 95.0% of glucose consumption and 0.74% (v/v) of bioethanol produced during the MFC process, while MFC without mediator generated 4.5×10-5 A of current, 0.689V of potential, 2.12×10-3 W/m2 of power density, 1.96×10-3 J of maximum energy, 96.3% of glucose consumption and 0.74% (v/v) of bioethanol produced. Power density yields from both type of MFC are still very low and not differ significantly. From the present study, it can be concluded that MB mediator only effected on potential yield in MFC using the condition applied in this study

Cytochrome P450 monooxygenases (P450s) are ubiquitous enzymes with high availability and diversity in nature. Fungi provide a diverse and complex array of P450s, and these enzymes play essential roles in various secondary metabolic processes. Besides the physiological impacts of P450s on fungal life, their versatile functions are attractive for use in advanced applications of the biotechnology sector. Herein, we report gene identification and functional characterization of P450s from the zygomycetous fungus Thamnidium elegans (TeCYPs). We identified 48 TeCYP genes, including two putative pseudogenes, from the whole-genome sequence of T. elegans. Furthermore, we constructed a functional library of TeCYPs and heterologously expressed 46 TeCYPs in Saccharomyces cerevisiae. Recombinants of S. cerevisiae were then used as whole-cell biocatalysts for bioconversion of various compounds. Catalytic potentials of various TeCYPs were demonstrated through a functionomic survey to convert a series of compounds, including steroidal substrates. Notably, CYP5312A4 was found to be highly active against testosterone. Based on nuclear magnetic resonance analysis, enzymatic conversion of testosterone to 14α-hydroxytestosterone by CYP5312A4 was demonstrated. This is the first report to identify a novel fungal P450 that catalyzes the 14α-hydroxylation of testosterone. In addition, we explored the latent potentials of TeCYPs using various substrates. This study provides a platform to further study the potential use of TeCYPs as catalysts in pharmaceutical and agricultural industries and biotechnology.