Difference between revisions of "Part:BBa K896006"

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	Cloning of NirN+NirS gene:		Cloning of NirN+NirS gene:
−	Ntrogen oxides are one of the mostnotorious pollutants in the modern days. At high temperature, nitrogen reactswith oxygen and form a binary compound of these two elements or a mixture ofsuch compound. These compounds are the main reason of smog and acid rain in theurban area; furthermore, they pose a major threat to the ozone in thestratosphere. The application of fertilizers and animal manure also result ingroundwater contamination by nitrate. Abnormally high nitrate concentrationcauses eutrophication and damages the environment. Anthropogenic disturbance ofNitrogen cycle accelerates the accumulation of nitrogen oxides, and suchsituation will deteriorate further if we aren’t devoted to solve the environmentalchallenge.<p></p>
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	Recently, thesearch for biological nitrogen removal method from wastewaters and exhaust airhas come up with several promising methods; however, most of them just tookadvantage of some special bacteria combined with industrial procedures. On thecontrary, our iGEM project aim to reduce nitrogen oxides and oxidize sulfidecompounds at the same time. During the processes of denitrification, sulfidecompounds and nitrate act as electron donor and acceptor respectively. Thisreaction is also known as sulfide-driven denitrification. Researchers havereported that E. coli can perform such reaction when expresses sqr gene from R. capsulatus. Herein, we enable certaintype of cyanobacteria to take advantage of sulfide and reduce nitrogen oxidecompounds into nitrogen. The BLAST result shows that sqr genes are homolog in R. capsulatus and Synechocystis sp. PCC 6803. For denitrification, we plan to getaccess to Thiobacillus denitrificans,the well-known chemolithotrophic organisms. Nevertheless, we later found itdifficult to obtain the specific strain we need. According to NCBI database,enzymes for denitrification such as nir, nor, nos share great similaritybetween Thiobacillus denitrificans andPseudomonas aeruginosa PAO1, so weadopted P. aeruginosa PAO1 instead andexpressed the enzymes mentioned above in Synechocystissp. PCC 6803. These denitrifying enzymes are functional under aerobiccondition, yet like all cyanobacteria, Synechocystissp. PCC 6803 produces oxygen during photosynthesis. Fortunately, whensulfide presents in the environment and sqr is expressed, it will ceaseproducing oxygen and use sulfide as an electron donor for carbon dioxidephotoassimilation. Together with dsrI and dsrII enzymes from Desulfovibrio desulfuricans, ourengineered organisms are capable of reducing three major oxides pollution –nitrogen, sulfur and carbon oxides.<p></p>		Recently, thesearch for biological nitrogen removal method from wastewaters and exhaust airhas come up with several promising methods; however, most of them just tookadvantage of some special bacteria combined with industrial procedures. On thecontrary, our iGEM project aim to reduce nitrogen oxides and oxidize sulfidecompounds at the same time. During the processes of denitrification, sulfidecompounds and nitrate act as electron donor and acceptor respectively. Thisreaction is also known as sulfide-driven denitrification. Researchers havereported that E. coli can perform such reaction when expresses sqr gene from R. capsulatus. Herein, we enable certaintype of cyanobacteria to take advantage of sulfide and reduce nitrogen oxidecompounds into nitrogen. The BLAST result shows that sqr genes are homolog in R. capsulatus and Synechocystis sp. PCC 6803. For denitrification, we plan to getaccess to Thiobacillus denitrificans,the well-known chemolithotrophic organisms. Nevertheless, we later found itdifficult to obtain the specific strain we need. According to NCBI database,enzymes for denitrification such as nir, nor, nos share great similaritybetween Thiobacillus denitrificans andPseudomonas aeruginosa PAO1, so weadopted P. aeruginosa PAO1 instead andexpressed the enzymes mentioned above in Synechocystissp. PCC 6803. These denitrifying enzymes are functional under aerobiccondition, yet like all cyanobacteria, Synechocystissp. PCC 6803 produces oxygen during photosynthesis. Fortunately, whensulfide presents in the environment and sqr is expressed, it will ceaseproducing oxygen and use sulfide as an electron donor for carbon dioxidephotoassimilation. Together with dsrI and dsrII enzymes from Desulfovibrio desulfuricans, ourengineered organisms are capable of reducing three major oxides pollution –nitrogen, sulfur and carbon oxides.<p></p>

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Revision as of 13:42, 22 September 2012

NirN-NirS (Nitrite->Nitric oxide reductase)

Cloning of NirN+NirS gene:

Recently, thesearch for biological nitrogen removal method from wastewaters and exhaust airhas come up with several promising methods; however, most of them just tookadvantage of some special bacteria combined with industrial procedures. On thecontrary, our iGEM project aim to reduce nitrogen oxides and oxidize sulfidecompounds at the same time. During the processes of denitrification, sulfidecompounds and nitrate act as electron donor and acceptor respectively. Thisreaction is also known as sulfide-driven denitrification. Researchers havereported that E. coli can perform such reaction when expresses sqr gene from R. capsulatus. Herein, we enable certaintype of cyanobacteria to take advantage of sulfide and reduce nitrogen oxidecompounds into nitrogen. The BLAST result shows that sqr genes are homolog in R. capsulatus and Synechocystis sp. PCC 6803. For denitrification, we plan to getaccess to Thiobacillus denitrificans,the well-known chemolithotrophic organisms. Nevertheless, we later found itdifficult to obtain the specific strain we need. According to NCBI database,enzymes for denitrification such as nir, nor, nos share great similaritybetween Thiobacillus denitrificans andPseudomonas aeruginosa PAO1, so weadopted P. aeruginosa PAO1 instead andexpressed the enzymes mentioned above in Synechocystissp. PCC 6803. These denitrifying enzymes are functional under aerobiccondition, yet like all cyanobacteria, Synechocystissp. PCC 6803 produces oxygen during photosynthesis. Fortunately, whensulfide presents in the environment and sqr is expressed, it will ceaseproducing oxygen and use sulfide as an electron donor for carbon dioxidephotoassimilation. Together with dsrI and dsrII enzymes from Desulfovibrio desulfuricans, ourengineered organisms are capable of reducing three major oxides pollution –nitrogen, sulfur and carbon oxides.

Moreover, ourproject has been put into practice thanks to the cooperation with Chung HwaPulp Corporation. The wastewater generated by Pulp factories contains enormoussulfide compounds and nitrate, which bring the annoying odors as well as thecontamination to the local environment. Fortunately, our project seems to bethe solution to their problem. This also demonstrates the potential andpossibility of commercialized our project. On top of that, the engineeredcyanobacteria can become the third endosymbiosis organelles with the help ofdivision inhibitor, gene for invasion. After installing our designation intoplants or even human cells as artificial organelles, we grant eukaryotes theability to survive in extreme environments as horrible as Venus in case thespace immigration is necessary on day.

Sequence and Features