Bacterial Batteries

Recently, a membrane was used to separate the anode and cathode compartments, and S. oneidensis MR-1 and other bacteria are added in both or only one of the electrode chambers [145]. It was observed that the electrochemical behavior of the copper electrode was significantly affected by the exposure condition. A second time constant was observed in the impedance spectra of copper that was partially immersed in the electrolyte, this can be attributed to the formation of a porous biofilm in the air/liquid/metal interface. Complete immersion of the electrode or deaeration of die electrolyte resulted in onetime-constant spectra. The corrosion potential increased with time for the Cu electrode partially immersed in the electrolyte, while it decreased for the other two exposure conditions. The mechanism on how the exposure condition affects electrode performance in bacterial batteries remains unclear [145]. 

While bacterial batteries hold a great promise for promoting the power output and long-term stability of galvanic cells, it has to be realised that. 

Schematic diagram of the bacterial battery developed by Ku et al. (Reprinted with permission from Corros. Sci., 47, E. Ku et al.. The concept of the bacterial battery, 1063-1069, Copyright 2005, Elsevier.)...

E. Ku , K. Nealson and R Mansfeld, The bacterial battery and the effect of different exposure conditions on biofihn properties, Electrochim. Acta 54,2008,47-52. 

Professor Bruce Ames, a biochemist at the University of California at Berkeley is one of the pioneers of this type of short-term testing. The Ames Test, as it is called, is now widely used, typically as one of several short-term tests that constitute a series of tests, or battery. A battery is thought necessary because no single test is adequate to detect all types of genotoxicity. The Ames Test involves the use of mutant strains of a common bacterium. Salmonella typhimurium, that back-mutate to their normal state in the presence of a mutagenic chemical or metabolite. Many other bacterial and mammalian cell systems have been made available for this type of testing. 

Slesinski RS, Hengler WC, Guzzie PJ, et ah Mutagenicity evaluation of glutaraldehyde in a battery of in vitro bacterial and mammalian test systems. Food Chem Toxicol 21 621-629, 1983... 

The silver ions used in the bacterial snsceptibility tests were released from pure silver electrodes using a 12 V battery-operated direct cnrrent generator. The apparatus used for silver ion generation was described previonsly in [13]. The water-based silver colloidal solution was obtained by a three-stage process based on the... 

The pT-index scale appraises the relative hazard of aquatic environmental samples by assigning them to a numerical class. As bioassays within a test battery are considered equal in rank, the most sensitive test with its pTmax-value defines the toxicity class of the test material. If, for example, an effluent yields pT-values of 7, 2, 8 and 0 for the bacterial, algal, daphnid and fish tests, respectively, its pT-index is therefore assigned to toxicity class 8, based on the most sensitive response obtained with the Daphnia test. Since, by convention, sample toxicity classes are designated by Roman numerals, the test material is then assigned to toxicity class Vm. A toxicity class is not a strictly defined value, but rather the consequence of the... 

Use of several laboratory toxicity tests (at least two), usually representative of different levels of biological organization (e.g., a battery composed of a bacterial, algal, microinvertebrate and fish test) to attempt to circumscribe the full toxicity potential of a liquid or solid matrix sample. Volume 2(1,8). 

Figure 9.10 is a plot of steepwater composition taken from successive steeps across a ten steep, continuous-flow battery in 1950 when process water used for steep acid provided a rich bacterial inoculum. Today s continuous countercurrent steep batteries have approximately the same types of changes in every property except relative... 

The reaction centre found in many purple non-sulphur bacteria is a simple example of a group of proteins that are natureis solar batteries. The reaction centre uses the energy of sunlight to generate positive and negative charges on opposite sides of the bacterial cytoplasmic membrane. This potential difference drives a circuit of electron transfer reactions that are linked to proton translocation across this membrane. 

As opposed to P-700 in PS I and to the cation radicals of the bacterial reaction centers, P-680 is difficult to trap in its oxidized state - even at low temperatures its lifetime following photogeneration is only 3-4 ms [90] - and chemical oxidation so far has not been possible owing to the high P-680 midpoint potential [1]. Consequently the battery of techniques, particularly magnetic resonance, which has proven fruitful in unraveling the structures of the other reaction center chlorophylls has not been applied to P-680. Its spin-polarized triplet has been detected [61,91] and its unexpected parallel orientation with respect to the membrane plane postulated. The zero-field splitting parameters are almost identical to those of... 

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