Improvement of Baker's yeast-based fuel cell power output by electrodes and proton exchange membrane modification.

The production of more efficient yeast-based fuel cells (YFCs) depends on a combination of effective proton exchange membranes, electron mediators and current collectors. The adhesion of organisms on electrode surface plays a key role in the electron transfer process optimizing the generated power density. In this work, it is reported the preparation of a new YFC prototype using membranes of polyvinyl alcohol/ phosphoric acid and anodes of carbon nanotubes/polyurethane. The high surface area for yeast adhesion and the strong interaction established between cells/carbon nanotubes favor the energy generation in fuel cell. To evaluate the influence of external mediators and the consumption of feed solution (glucose) on performance of YFC, the kinetics of current generation of resulting fuel cells was analyzed. Results reveal that increases in the impedance of electrodes on generated power can be minimized by periodical infusion of feed fuel, preserving 70% of maximum power, representing an important condition for prolonged activity of fuel cell.

A Literature Investigation about Electrospinning and Nanofibers: Historical Trends, Current Status and Future Challenges.

The development of new fibrilar materials based on electrospinning (ES) technique has a notable history of nearly four centuries of discoveries and results. The eletrospinning manufacturing is one of the most widely reported methods for nanofiber (NF) manufacturing, providing security, high quality and productivity. In spite of the first patent about electrospinning has been applied in April 5(th), 1900 by John Francis Cooley, a historical perspective (since 1600s) about this amazing discovery represents an important step for future applications. Nanofibers have been considered one of the top interesting fundamental study objects for academicians, and greatest intriguing business materials for modern industry. As a consequence, lucrative organizations and companies have explored the relevance of nanofibers. In this paper, the quantity of published manuscripts and patent inventions is presented and the correlation of research activities to the production of new electrospinning materials is shown. China and the United States have been leading in electrospinning and nanofibers development. The company triumph is mostly dependent on applications improvement relevant for broader business society. A dramatic rise of interest in nanofibers produced by electrospinning technique has been confirmed due to the publication data, author's affiliation, keywords, and essential characterization procedures. Is has been shown that the number of publications on electrospinning and nanofibers researches from academic institutions is higher than industrial laboratories. More than 1,891 patents using the term "electrospinning" and 2,960 with the term "nanofibers" according to the European Patent Office at title or abstract have been filed around the world up to 2013. These numbers just continue to increase along with worldwide ES-related sales. Curiously, for the same period 11,973 electrospinning documents and 18,679 nanofibers-related (mainly manuscripts) were published considering the Scopus database with the same terms in the title, abstract or using keywords. Thus, statistically, there are more published manuscripts worldwide than patents for both keywords.