Team:Shanghai HS/Description
Inspiration
Our idea is from iGEM team SBS_SH_112144 last year, however, the solution strategy is different. Their team focus on the cyanophage lysozyme to degrade the cyanobacteria, and we focus on microcystin degradation in water. Every summer, the outbreak of cyanobacteria puzzles numerous countries in the world. It causes insufficiency of oxygen in the waters, and the release of a poisonous substance called microcystin, which, even in small amount, causes serious diseases like liver cancer. However, the current method of removing microcystin is still inefficient or produces secondary pollution. Here we utilize enzyme MlrA, which is able to degrade microcystin, to solve the pollution. The mlrA genes from several different speices are expressed in E. coli and purified. The results show the microcystin is degraded with mlrA by HPLC (High Performed Liquid Chromatography). Furthermore, we try to design a device which is commercially mass produced and can be utilized by the waterworks or even at home. We anticipate our solution to aid in protecting the environment and avoiding people from getting sick because of drinking contaminated water.
Description
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microcystin
Cyanobacteria release some toxic chemicals when its cells are dead or dissolved. When released, toxins may sustain for weeks to months. These toxins which are produced by cyanobacteria are generally called microcystins. Its pollution has already been a serious environmental problem in China. It causes eutrophication in the water, thus resulting in the rampant growth of some algae. Microcystins can enter the human body through the digestive tract, then causing diarrhea, nerve palsy, liver damage, and severe poisoning or even death1.
Microcystin’s chemical properties are quite stable. For instance, its solubility in water is greater than 1 g/L, so it means that its natural degradation process in water is pretty slow. Moreover, microcystins can resistant in the high heat conditions2. -
cyanobacteria and water bloom
Cyanobacteria is a very small and primitive algae that have a tenacious vitality. when the water bodies are eutrophicated , cyanobacteria will greatly outnumber other species. In addition, cyanobacteria have many secretions that supplant other species and replaces their ecological niche3.
Cyanobacteria secrete microcystin as they develop and absorb oxygen during the decomposition process after they die. Living things (including edible algae) will die due to the lack of oxygen, forming a vicious cycle3.
The illegal discharge of nitrogen salt and phosphateinto waterbodies by factories is the major cause of eutrophication in fresh waters. High levels of limiting nutrients provides an extremely suitable growth condition for blue-green algae, In May and June 2007, severe cyanobacteria pollution broke out in Taihu Lake, Jiangsu Province, China, which directly caused the pollution of tap water in the whole city of Wuxi.However, rather than being suppressed, the threat water blooms poses has became even more and more severe. The occurrence of blooms are getting earlier each year, and the duration is becoming longer. The outbreak of water bloom will bring immeasurable losses. -
mlrA
Microcystinase-LR A, MlrA is encoded by gene mlrA-2 or mlrA-3. MlrA in short, is an enzyme that can biologically degrade the most common and harmful form of microcystin. MlrA break down the microcystin by cutting one of the amide linkages in the monocyclic heptapeptides. In such way, the structure of microcystin can be linearized and the toxicity can be removed. The product of this process provides us with a 160 times less toxic peptide, and a much safer water source4,5.
Based on the known principles, we are able to build a device containing immobilized MlrA, so that the microcystin in the water flowing through the device can be broke down. Sewage treatment plant can finally solve the problem of traces of microcystin in water after routine treatment. -
Our goal
Regular water treatment and distillation is not able to break the ring structure of microcystin, Which is difficult for people to degrade them through normal methods.
Our team looks forward to using a biological method, enzymatic breakdown, to degrade microcystins.
Reference
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Berdalet E, Fleming L E, Gowen R, et al. Marine harmful algal blooms, human health and wellbeing: challenges and opportunities in the 21st century[J]. Journal of the Marine Biological Association of the United Kingdom, 2016, 96(1): 61-91.
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Garcia A C A, Rodrigues M A S, Xavier J L N, et al. Degradation of cyanotoxins (microcystin) in drinking water using photoelectrooxidation[J]. Brazilian Journal of Biology, 2015, 75(2): 45-49.
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Kimambo O N, Gumbo J R, Chikoore H. The occurrence of cyanobacteria blooms in freshwater ecosystems and their link with hydro-meteorological and environmental variations in Tanzania[J]. Heliyon, 2019, 5(3): e01312.
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Kimambo O N, Gumbo J R, Chikoore H. The occurrence of cyanobacteria blooms in freshwater ecosystems and their link with hydro-meteorological and environmental variations in Tanzania[J]. Heliyon, 2019, 5(3): e01312.
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Zhang J, Lu Q, Ding Q, et al. A novel and native microcystin-degrading bacterium of sphingopyxis sp. Isolated from lake taihu[J]. International journal of environmental research and public health, 2017, 14(10): 1187.
About Us
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ConsultationContact Info
- Rock St 12, Newyork City, USA
- (000) 000-000-0000
- Medizco@gmail.com
- Week Days: 09.00 to 18.00 Sunday: Closed
