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One of the objectives of the project is the dissemination of innovative idea of biofuels elements among the younger generation.

INNOVATIVE MICROBIOLOGICAL FUEL CELLS AS GREEN POWER SOURCES

(Contract D002-163/2008 with Bulgarian National Science Fund)

Project leader: Assoc.Prof. Mario Mitov, PhD

Partner organizations:

South-West University “Neofit Rilsky” – Blagoevgrad, Bulgaria
(Team leader: Assoc.Prof. Mario Mitov, PhD)

Plovdiv University “Paisii Hilendarski” – Plovdiv, Bulgaria
(Team leader: Assist.Prof. Yolina Hubenova, Dr.rer.nat.)

Institute of Electrochemistry and Energy Systems – BAS, Sofia, Bulgaria
(Team leader: Assoc.Prof. Anastatsia Kaisheva, PhD)

Institute of Physicochemistry “Acad. Rostislav Kaishev” – BAS, Sofia, Bulgaria
(Team leader: Assoc.Prof. Rashko Rashkov, PhD)

Contract duration: 3 years

Anotation:
The aim of this project is a verification of possibilities for conversion of bioenergy into electricity by development and testing of biofuel cells, utilizing whole microorganisms and/or isolated enzymes. The implementation of the project will be based on interdisciplinary investigations, requiring cooperation of specialists in biochemistry, microbiology, electrochemistry and engineering. A complex microbiological and biochemical analysis will be carried out for preliminary selection of proper microorganisms (prokaryotes and eukaryotes), which will be further tested in a model biofuel cell. Various traditionally used and novel synthesized materials will be studied as potential electrodes and separators. The selection of appropriate mediator will be done on the base of cytotoxicity tests as well as electrochemical measurements. An optimization of the microorganisms-mediator-electrode system as well as the whole biofuel cell performance in regards to improvement of its output characteristics (cell voltage, generated current and power density) will be also carried out. In addition, isolated enzymes will be immobilized and also tested in a model fuel cell. The expected results from realization of the project are: development of a biofuel cell, based on the use of whole microorganisms and/or isolated enzymes; development of a set of methods for testing the separate components and the whole fuel cell system; construction of lab stand for testing and demonstrations; interdisciplinary training of students and specialists; transfer of knowledge and know-how to specialized enterprises. In more global aspect, the expected future economical and ecological effect is related both to green electricity production and waste water treatment technologies.

SUMMARY OF THE CURRENT RESULTS

A complex methodology for selection and characterization of microorganisms as potential biocatalysts in microbial fuel cells (MFC) has been developed. On this basis, over 30 microorganisms’ strains have been studied for electrogenic properties. Twelve of them are determined as electrogens. Three types of electrochemical cells have been constructed: double-chamber fuel cell with a salt bridge, double-chamber fuel cell with ion-exchange membrane and single-chamber fuel cell. A significant increase of the generated current and power density have been achieved by the improvement of MFC construction. The MFC current and power increase in order graphite rods < carbon cloth < carbon felt < Ni-nanomodified carbon felt (potentiostatic pulse method) < Ni-nanomodified carbon felt (galvanostatic pulse method). Among potassium ferricyanide, potassium permanganate, hydrogen peroxide, ammonium vanadate and ferroin, the potassium ferricyanide has been determined as the most appropriate catholyte for long-term operation. The highest MFC-characteristics have been obtained by using Methylene blue as a exogeneous medaitor. A mediatorless MFC has been realized by applying nanomodified anodes. The achieved maximum values of current density (5.5 A/m2) and power density (720 mW/m2) are the highest for yeast-biofuel cell up-to-now. An idea for electricity generation from bacteria-plant system has been realized by using bryophyta Dicranum montanum and the symbiotic co-existence with microorganisms in its ryzoids. The stability of a single-chamber Bryophyta–MFC system has been approved for over ten months. Open circuit voltage between 600 and 1000 mV and current density up to 50 mА/m2 (at load resistance 1 k?) have been recorded under semi-natural conditions, while only water has been added to the system.

Completed project: METAL HYDRIDE – AIR FUEL CELL
(Contract D01-368/2006)