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Team:Osaka/Project
From 2010.igem.org
Project: The Continuous Greening Cycle
Background
Arid regions tend to experience large fluctuations in precipitation. In those regions, rainfall tends to be infrequent and brief but in heavy volume, leading to erosion of and leeching of nutrients from the soil. Also, drought sometimes occur for long periods, hindering the growth of vegetation. According to some reports, precipitation is correlated to plant cover; consequently a vicious cycle of reduced precipitation and loss of vegetation is induced, finally leading to desertification. over-grazing and over-cultivation are among the human causes of desertification population increase in arid regions of developing countries fuels need for higher food production - expansion of agriculture and livestock grazing area already low productivity - stressed beyond capacity - rapid loss of fertility instead of restoring this exhausted land, which is difficult, further expansion to new areas reforestation, irrigation system - not successful 沙漠化した土地は荒廃しており水分も少なくなっています。 その様な土地に無計画に植林することは土地の劣化を速めてしまいます。 また、灌漑は設備の設置や維持に費用が掛かり、設備の運転には多くのエネルギーが必要です。 十分量の水を供給できなければ土壌中の塩類が地表面に集積してしまい植物が育たなくなってしまいます。 In searching for a way to apply bioengineering to the problem of desertification, low cost, low energy, sustainable desert greening that can be easily implemented in developed and developing countries alikeObjectives
We had 3 objectives in mind when planning this project:
- To address environmental issue of desertification
- To investigate the feasibility of engineering a cyclic biological system
- To contribute to iGEM and Synthetic Biology by developing and characterizing new parts
The Cycle
We envisioned a Continuous Greening Cycle in which engineered microorganisms decompose plant fibers into nutrients through the action of cellulolytic enzymes. They then produce water-holding polymers such as poly(gamma-glutamic) acid that retain water in the soil to help plants grow. When the plants die they will be decomposed to start the cycle anew.
Watch the animation of our project.
Cellulose degradation
Polyglutamic acid (PGA) synthesis
Gamma polyglutamic acidParts
Construction of the parts for cellulose degradation and PGA synthesis outlined above formed the majority of our wet lab work. We produced a collection of new BioBricks by PCR from existing plasmids or genome DNA, and also made some constructs to test the new parts. For more info, please see Parts.
Tests
We ran several tests to confirm the working of our parts, as well as characterize them quantitatively. See the Tests page for more info.
Modeling
We also attempted to construct a model and simulate it using software in order to determine the feasibility of the cycle as well as identify important parameters involved. See the Modeling page for more info.
