As environmental awareness rise, recycling paper has been indispensable in our daily routine. However, in the paper recycling procedure, chemical deinking created harmful byproducts which are released to the environment. To solve this problem, we found that enzymatic methods have the potential to remove ink particles from paper fibers more efficiently and result in lower fiber damage compared to chemical agents. In our project, we combine a photo-inducible system to stimulate the production of xylanase, glucanase,and lipase in yeast. Yeast is our model organism. We chose yeast due to three reasons: first, it is able to secret enzymes; second, the enzymes we are using are of fungal origin; third, our light-inducible system is also of fungal origin. After construct been built, three constructs will be sent into yeast. Our yeast can be stimulated by red light and start our enzyme secretion.
In the enzymatic deinking process, our project mainly focus on three deinking enzymes, such as xylanase, glucanase, and lipase. However, there are many different kinds of organism producing these enzymes, and the amino acid sequences are slightly different from each other. In order to find out the enzymes which have the best deinking efficiency, Information and Simulation group has utilized several software and technique to analyze hundreds of enzymes’ binding affinity with their ligand, and provided the result to bio-development group for constructing biobricks. We have firstly searched the templates of related homologous proteins by using SWISS-MODEL, and downloaded all these protein 3D structure files from RCSB protein data bank. Before performing protein docking, the protein conformation problem is fixed, and the energy minimization of ligands is also done by using Discovery Studio in order to increase the accuracy of result. Another simulation software, AutoDock can simulate the docking between enzyme and ligand, and helps to calculate the binding affinity. We have ranked the binding affinity of hundreds of enzymes, and visualized the top 10 docking situation by using PyMOL. Consequently, the bio-development group able to construct the plasmid base on this docking result. Furthermore, Information and simulation group has also built the wiki page to present our project, the enzymatic deinking developed by 2017 iGEM CGU Taiwan team.
It is localizing the reaction of enzyme on the paper that can reach our two goals, reducing the pollution from deinking and maintaining the fibers without inks to keep the strength of the reprocessed paper. Thus, we have created a new device to reform the procedure to make reprocessed paper. Briefly describing the function of the device, the paper will be drew into the box and took a picture to be analyzed the distribution of the surface area of ink. Then, the engineered yeast will be sprayed on the ink part on the paper to be induced to secrete out enzyme only on the ink part. Thus, the enzyme can be precisely working on the ink part of the paper to preserve the other fibers without the ink on the paper. Additionally, our concept has been confirmed by the procedure we made reprocessed paper in lab. We believe our enzymatic deinking process can fulfill our dream with this innovative device.
Paper is one of the most common natural resources we used in everyday life. The invention of paper allowed human to record knowledge and spread information rapidly. In modern world, the enormous amount of paper usage is decreasing the tree density around the globe. Paper reuse is a strategy of reducing tree cut, but recycling paper isn’t an easy job. Paper are made of different fibers depending on the manufacturing process, and printed with different inks. These reasons increase the difficulty of turning the pulp clean and ready for use. Deinking is the process which separates the ink and paper fiber during the cleanup of reprocessed paper pulp. The deinking process in the industry use chemical reagents like detergent, alkali which would cause water pollution and air pollution. Our plan is to replace the chemical reagents with biological enzymes, turning the waste into an environmentally friendly organic compound. We are going to create a controllable enzyme secrete system which would extend the limit of deinking and be more eco-friendly.