Team:LZU-China/background

       China, as the world largest developing country, suffers serious pollution in 21 century. Lanzhou, a capital city in northwest of China, bears serious contaminations. For example, in April 2014, this city has started panic-buying bottled water after city authorities confirmed that lethal chemical compound benzene contaminated the city's drinking water system. We have conducted a survey about how the population's concern about the water contaminations. It shows that compared with UK where exactly 70.59% of the residents announce that did not suffer from any kinds of water pollution, 69.23% of the Chinese respondents admitted that their hometown has effected by water pollution. In particular, 15.38% of them said that they had suffered serious pollution. Meanwhile, over 78.46% of the residents in China suggest it should be meaningful to develop microbial fuel cells for power generation. So those are why we want to start the topic about sewage treatment using membrane and power generation using microorganisms.

       Microorganisms can degrade pollutants and produce electricity, so we aimed to produce microbial fuel cells (MFCs) to deal with the pollutant and generate electricity. This is really a new kind of technology for human because the world best MFCs can only run a tiny toy engine, so this should be have a bright future when it comes into practice.
At first, we construct a normal MFC, using Shewanella oneidensi to generate electricity and reduce sewage with heavy metal ions, during several experiments we found that MFCs running in traditional way have many disadvantages. These two we will mention as following are extremely serious.
       One is that pollutant, for example, p-Nitrophenol(PNP), exists in common sewage, always impede the electricity generation of MFC.

       Another drawback is that all kinds of traditional MFCs are hard to show the contaminants concentrations. In the past, some scientist and engineers had to use costly method for example High Performance Liquid Chromatography (HPLC) measure the substrate concentration. This is also a major drawback for MFCs applications.

      But how can we deal with these two kinds of problems? We noticed that if we could modify the gene of bacteria used in MFCs to fight against the negative effect of pollutant and invented a series of hardware and software to monitor the substrate concentration of MFCs, these two kinds of problems would be overcame successfully. So we registered iGEM 2014 to develop a novel MFCs system that can measure substrates concentrations using genetic engineered bacteria. This is a new concept not only simply for PNP problem, but also it is a standard model for all kinds of pollutant treatment and real-time substrate concentration monitoring.