Team:Xiamen City

Team name: Xiamen_City

Project description:

In March 21st, 2019, a chemical storage tank containing m-Phenylenediamine(C6H4(NH2)2) in Jiangsu province, China, exploded without any indication, which killed almost 80 people and caused hundreds of injuries. m-Phenylenediamine, listed as IARC Group3 carcinogens since 2017, is toxic, combustible and unstable when exposed to the air. Chemical leakage will contaminate nearby underground water system and seriously damage aquatic ecosystem. Inhaling of m-Phenylenediamine or touching the chemical directly can cause allergy, kidney failure and circulatory diseases. Accumulation and explosion of m-Phenylenediamine has become a threaten towards both the environment and human beings. However, until now, people do not have a cost effective and convenient way to degrade m-Phenylenediamine. Neither chemical nor physical degradation plan works well in this case. Another approach soon comes to our mind, microbial biodegradation. During literature reading, we find laccase, usually used as strong oxidant, can degrade toxic chemicals which have similar chemical properties as m-phenindamine, such as phenol, anilines and benzenethiols. So, we hypothesize that the enzyme has the potential to survive in m-phenindamine, even to degrade it. We construct the gene of laccase into the plasmids of E.coli, and make the genetically modified bacteria undergo adaptive laboratory evolution (ALE), allowing phenotypic changes to be clearly associated with a certain growth environment that leads to the selection of traits. ALE is expected to generate evolved E.coli that can grow in m-phenindamine. Then we apply high-performance liquid chromatography (HPLC) to test whether there is successful degradation of m-phenindamine and determine products of the reation. If the answer is yes, we will find genes related to the mechanism of degradation using whole genome sequencing and then overexpress related genes to further improve genetically modified E.coli’s ability to degrade m-phenylenediamine.