Introduction

With the entrance into 21st century, enormous new techniques and innovations are expanding rapidly, people’s demands of high-quality life are rising along with. Industrial water consumption increased, so as domestic water consumption. In the decade between 2008 to 2018, the total water consumption in Macau increased more than 20 million cubic meters. However, according to the official statistics from DSEC Macau, the daily average of total suspended solids in the waste water treated at the WWTP in Coloane exceeded the limit value by 276.7% in 2017. A new advanced solid-particle collection technique is in an urgent need.

Our team, as a participant in the 2019 International Genetically Modified Machinery (iGEM) competition, aim to apply the synthetic biology into society by engineering a controllable nanoparticle/microparticle collector microorganism via bacteria aggregation in the process of wastewater treatment. Additionally, via a magnetic field, we would achieve a goal of microorganism immobilization to eventually collect the nano- or micro- particles in wastewater. Its capabilities in collecting nanoparticles will be applied to remove possible pollutants, particularly those undegradable pollutants, such as heavy metal mercury, phosphate, total nitrogen, ammonia nitrogen, and organic compounds. The success of our project would provide a cheap and renewable organism that we can use to clean up particles at the nano- or micro- levels. We are targeting at particle-free water release, and treated water can be educed into natural water or used for domestic supply after post-treatment.

Our project is inspired by a literature, “Preparation of Sticky Escherichia coli through Surface Display of an Adhesive Catecholamine Moiety” published by a Korean research team in 2014. Based on the idea of engineering a bacteria with sticky feature on its cell surface, we would like to focus on the structure and characteristics of the sticky domain of the engineered E. coli and enhance its effectiveness and efficiency in capturing nanoparticles by transforming the E.coli with a variety of plasmid constructs. With the improved version of E. coli, it is expected to be capable in capturing those pollutants mentioned above which are currently a noteworthy issue in wastewater treatment. Our project is noticeable because the advanced sticky feature on E. coli is expected to be capable in binding on almost all surface materials.