Team:SHSBNU China/Human Practices
Human Practice
I. Overview
After setting our goal to decompose synthetic dye with laccases, we seek to find out more information of biological sewage treatment and practical problems that required to be addressed. We also want to find out how our project can be applied to real world sewage treatment, and what change should we make to improve our project.
Therefore, we visited Hanghua sewage plant（World Trade Center, Beijing, China). Hanghua sewage plant is experienced in using biology method to decompose pollutant while they also had used other ways, including chemical and physical methods. Mr. Li, the manager of the sewage plant, told us lots of information we needed.
II. Silver
During the interview, we found out the situation of each current methods
a. Chemical and Physical Methods
First of all, we learned that their previous chemical and physical techniques such as active carbon adsorption and oxidation method, being expensive in cost for both methods, the sewage plant had to switched to biological treatment.
b. Biological Method
Hanghua sewage plant mainly uses integrated sewage treatment device, in which a critical step is to add bacteria to decompose pollutant. Specially engineered bacteria are able to reproduce rapidly in sewage water, and this allows the factory to process waste water with relatively lower financial requirement.
However, the bacteria used in sewage treatment may release toxic gases such H2S. The plant has to turn on the ventilation system periodically, which consumes large amount of electric power and produce loud noise. As time goes by, the advantage of lower cost is offset by electricity bills, and the higher payment for their workers working unfriendly work environment.
In traditional biological treatment method, bacteria are usually injected into waste water directly, floating, growing, as well as continuously being removed by the outflow. The dynamic balance of bacteria concentration might be broken by increasing the total flow of sewage water. Under extreme circumstances, growth rate of bacteria might be overwhelmed by the loss rate through outflow. Moreover, workers in the sewage treatment plant told us, due to wear and tear since 2003, and other undiscovered problems, the total ability of sewage treatment had dropped 40%. To address this issue, we need to develop a sustainable consumptive material.
III. Integrated Human Practice
a. Effectiveness of our project
According to the information from our human practice, we came up with the idea to use biofilm and laccase as the solution to the problem, since biofilms may form and firmly attach to living and non-living surfaces, the bacteria living in biofilms could organize themselves into a coordinated functional community in which they can share nutrients and be sheltered from erosion of sewage.
Moreover, because the laccase processes the sewage without releasing any toxic substance, it eliminates the unnecessary cost of using extraction pump and extra employee payment, which as a result enables factory to utilize the biggest advantage of biology method, inexpensive price.
b. Integrated Human Practice
Though our project is capable of dealing with the issue of current biology treatments, inspired by the human practice and our model of flowing water, we detected some critical factors that is worth to consider and adjust our project based on it for better effect under realistic condition.
The first one is the speed of water flow which has a serious influence on effectiveness of bacteria, since the difference of sewage's speed causes the difference in the time of contacting with substance required to decompose. Therefore, we adjust our project from two aspects, controlling the speed of sewage and increasing the efficiency.
As for controlling water flow, we design a hardware which is readily to replace and equipped with the regulated intake and outlet to monitor and adjust it by the reliable data system resulted from our model.
As for the reaction efficiency, we use SpyCatcher and SpyTag system to add the secreted endosporic laccase onto biofilm. For as much as it uses to increase the operating area of biofilm without that occupied by bacteria, there are more amount of laccase on the same unit area, which indicates the increasing in disposal efficiency.
The second one is the competition among bacteria. Through human practice, we realized that the realistic condition of sewage disposal is complicated, which means that there is usually more than one species of microorganism in the same environment. Therefore, our team decides to design a platform to help the growth of our bacteria, since once our bacteria forming biofilm, they share nutrients and defend the intruder together, which enables them to compete with other bacteria. We use PHA beads and growth our modified microorganism onto beads' surface. PHA can also work as the carbon source, and evidently effective in reducing the time of biofilm formation by providing nourishing nutrients. Moreover, to separate our microorganism from intruders, we are looking for the proper size of PHA plastic and integrate them inside our hardware to achieve our goal.
c. Conclusion
In conclusion, through the biology method, we found that the expensive cost and decreasing effectiveness are two main problems required to be addressed, and came up with the idea of designing our Biofilm x Laccase system as a potential solution. For the future plan, we are going to adjust our project from controlling flow rate of water by hardware and helping the growth of our bacteria by using Bluepha PHA plastic and isolated environment to coordinate the realistic world.
IV. Public Education and Engagement
Our public education includes two sections: on campus and off campus activities.
On campus, we design and implement a layered education system, starting from series of lectures to all students, interviewing some students and evaluating their potential of being iGEMers, then our synthetic biology club offering them training in genetic engineering.
Off campus, we established the collaboration with sewage plant for exchanging the instructive information including biology, plant and policy. We strongly believe that the practicability of our project would attract more plants even business companies to cooperate with us.
a. On campus part
We conducted lectures of iGEM projects and synthetic biology techniques to students on Tuesday and Thursday weekly. At the start of our education program, we briefly introduced our project's purpose, effectiveness and future potential contribution to the environment. We also invited students who were interested in improving the environment by synthetic biology technologies. After that, we held a series of lectures explaining the molecular mechanism, and prove practicability of our project to the students who followed up our project.
For the whole process of education, we put a high value on the effectiveness of lecture. Therefore, we required students who is willing to cooperate our work to register their WeChat account, and asked randomly 75% of students each time to share their perspectives, so we could adjust and improve the content of our lecture. We also interviewed students to find future iGEMers.
Furthermore, in our synthetic biology club, we introduced some basic methods and techniques of genetic engineering such as DNA extraction, restriction enzyme digestion, Primer design, and PCR, reserving talented students for our further iGEM projects.
In general, our on-campus education program comprehensively passed on our experience in iGEM and synthetic biology knowledge. Our program had also triggered students’ concern on environmental problems, as well as their passion for learning synthetic biology and becoming a qualified iGEMer.
b. Off campus part
During the visit of a sewage treatment plant, we briefly introduced our project to work leaders, then we showed reliability of our project and resolution to protect the environment. On one side, sewage treatment plant helped us conduct the design of our program by providing first-hand information of sewage plant. On the other side, we offered more information of our modified biology treatment. As a result, both sides were looking forward to establishing a long-term collaboration.
