Power generation via glycerol in Pseudomonas aeruginosa fuel cells was evaluated under improved culture conditions using two different electrochemical systems. One used Pt-black carbon felt air cathodes and proton exchange membranes. The other used ammonia pre-treated carbon felt electrodes immersed in ferricyanide as cathode and saline bridges as a cation exchange system. In all cases, ammonium pre-treated carbon felts were used as anodes. Experiments were conducted during 120 h at 37°C. Biochemical parameters such as microbial growth, substrate consumption and pyocyanin production were evaluated. Electrochemical studies of chronoamperometry, power output generation and coulombic efficiency (CE) were also performed. Initial concentrations of 25 g L−1 of pure glycerol were used. Small differences between systems, in terms of PCN production, glycerol consumption or microbial growth were observed. Also, good results in terms of current densities (Idmax) of 42 ± 2.1 μA cm−2, CE of 48 ± 2.4% and power output densities (Pdmax) of 350 ± 17.5 mW m−2, were achieved. The power output densities were at least 4 times higher than other previously reported MFCs based also on PCN production from pure glycerol or glucose. In contrast, when both systems were supplemented with raw glycerol obtained as by-product from biodiesel industry, lower values for Idmax, CE and Pdmax ranging 23 ± 1.15 μA cm−2, 36 ± 1.18% and 240 ± 12.0 mW m−2, were respectively achieved, depending on the electrochemical system used.

Leifsonia xyli subsp. xyli (Lxx) causes ratoon stunting disease (RSD) in sugarcane, and is one of major causes of production losses. The detection of Lxx bacteria in sugarcane is made mainly through molecular biology techniques, especially polymerase chain reaction (PCR). However, PCR presents some barriers to provide reliable results. The present work brings a Nanoparticle-assisted Polymerase Chain Reaction (NanoPCR) assay for the detection of Lxx in its latent infection on micropropagated sugarcane. This assay was based in the addition of Gold and Titanium dioxide nanoparticles to conventional PCR and evaluation of its effects. It was observed that the reactions performed with Titanium dioxide nanoparticles provided the formation of singular well-defined bands under electrophoresis, consistent with the expected molecular weight, without occurrence of non-specific bands or presenting false negatives occurrence, negative effects that were observed in the control assay. While the performed NanoPCR adding AuNP also provided the formation of well-defined bands, been able to inhibit the occurrence of false negatives, but wasn't able to eliminate the occurrence of non-specific amplifications. The results indicate that NanoPCR by the addition of Gold and Titanium dioxide nanoparticles to conventional PCR increased the detection of Lxx.

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