Difference between revisions of "Team:NPU-China"

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                 <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1">
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                 <button type="button" class="navbar-toggle" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1"> <span class="sr-only">Toggle navigation</span> <span class="icon-bar"></span> <span class="icon-bar"></span> <span class="icon-bar"></span> </button>
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                    <span class="sr-only">Toggle navigation</span>
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                 <a class="navbar-brand" href="https://2017.igem.org/Team:NPU-China">
 
                 <a class="navbar-brand" href="https://2017.igem.org/Team:NPU-China">
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                    <img src="https://static.igem.org/mediawiki/2017/2/29/NPU-logo.png" style="max-width:50px;margin-top:-10px;">
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                  <img src="https://static.igem.org/mediawiki/2017/2/29/NPU-logo.png" style="max-width:50px;margin-top:-10px;">
 
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                 <ul class="nav navbar-nav navbar-right">
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                     <li>
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                     <li class="active"> <a href="https://2017.igem.org/Team:NPU-China">Home</a> </li>
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                        <a href="https://2017.igem.org/Team:NPU-China">Home</a>
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                     <li class="dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Team<b class="caret"></b></a>
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                        <a href="#" class="dropdown-toggle" data-toggle="dropdown">Team
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Aboutus">About us</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Aboutus">About us</a>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Attributions">Attributions</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Attributions">Attributions</a>
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                            </li>
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                         </ul>
 
                         </ul>
 
                     </li>
 
                     </li>
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                     <li class="dropdown active">
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                     <li class="dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Project<b class="caret"></b></a>
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                        <a href="#" class="dropdown-toggle" data-toggle="dropdown">Project
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                            <b class="caret"></b>
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                        </a>
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                         <ul class="dropdown-menu">
 
                         <ul class="dropdown-menu">
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                             <li>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Background">Background</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Background">Background</a>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Description">Description</a> </li>
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                            </li>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Design">Design</a> </li>
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                             <li>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Model">Model</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Description">Description</a>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Proofofconcept">Proof of concept</a> </li>
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                            </li>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Demonstrate">Demonstrate</a> </li>
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                             <li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Design">Design</a>
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                            </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Model">Model</a>
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                            </li>
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                             <li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Proofofconcept">Proof of concept</a>
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                            </li>
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                             <li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Demonstrate">Demonstrate</a>
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                            </li>
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                         </ul>
 
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                     <li class="dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Parts<b class="caret"></b></a>
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                        <a href="#" class="dropdown-toggle" data-toggle="dropdown">Parts
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/BasicParts">Basic Parts</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/BasicParts">Basic Parts</a>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/CompositeParts">Composite Parts</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/CompositeParts">Composite Parts</a>
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                            </li>
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                         </ul>
 
                         </ul>
 
                     </li>
 
                     </li>
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                     <li>
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                     <li> <a href="https://2017.igem.org/Team:NPU-China/Hardware">Hardware</a> </li>
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                        <a href="https://2017.igem.org/Team:NPU-China/Hardware">Hardware</a>
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                     <li class="dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">HP<b class="caret"></b></a>
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                    </li>
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                     <li class="dropdown">
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                        <a href="#" class="dropdown-toggle" data-toggle="dropdown">HP
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                            <b class="caret"></b>
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                        </a>
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                         <ul class="dropdown-menu">
 
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                             <li>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/HP/Silver">Silver</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/HP/Silver">Silver</a>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/HP/Gold_Integrated">Gold</a> </li>
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                            </li>
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                             <li>
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                                <a href="https://2017.igem.org/Team:NPU-China/HP/Gold_Integrated">Gold</a>
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                            </li>
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                         </ul>
 
                         </ul>
 
                     </li>
 
                     </li>
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                     <li>
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                     <li> <a href="https://2017.igem.org/Team:NPU-China/Collaborations">Collaborations</a> </li>
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                        <a href="https://2017.igem.org/Team:NPU-China/Collaborations">Collaborations</a>
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                     <li> <a href="https://2017.igem.org/Team:NPU-China/Achievements">Achievements</a> </li>
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                    </li>
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                     <li> <a href="https://2017.igem.org/Team:NPU-China/InterLab">InterLab</a> </li>
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                     <li>
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                        <a href="https://2017.igem.org/Team:NPU-China/Achievements">Achievements</a>
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                    </li>
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                     <li>
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                        <a href="https://2017.igem.org/Team:NPU-China/InterLab">InterLab</a>
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                    </li>
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−
                     <li class="dropdown">
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                     <li class="dropdown"> <a href="#" class="dropdown-toggle" data-toggle="dropdown">Notebook<b class="caret"></b></a>
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                        <a href="#" class="dropdown-toggle" data-toggle="dropdown">Notebook
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                        </a>
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                         <ul class="dropdown-menu">
 
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                             <li>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Labnotes">Labnotes</a> </li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Labnotes">Labnotes</a>
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                             <li> <a href="https://2017.igem.org/Team:NPU-China/Protocols">Protocols</a> </li>
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                            </li>
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                             <li>
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                                <a href="https://2017.igem.org/Team:NPU-China/Protocols">Protocols</a>
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                            </li>
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                         </ul>
 
                         </ul>
 
                     </li>
 
                     </li>
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     </nav>
 
     </nav>
  
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     <!-- Header Carousel -->
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     <div class="batu" style="background: url('https://static.igem.org/mediawiki/2017/f/fe/Npu-background.png') no-repeat fixed; overflow: hidden;">
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     <header id="myCarousel" class="carousel slide">
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         <img class="img-responsive" src="https://static.igem.org/mediawiki/2017/b/bc/%E9%A2%98%E7%9B%AE%E5%B0%8F%E9%80%9A%E6%A0%8Fbackground.jpg">
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        <!-- Indicators -->
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            <li data-target="#myCarousel" data-slide-to="0" class="active"></li>
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             <li data-target="#myCarousel" data-slide-to="1"></li>
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            <li data-target="#myCarousel" data-slide-to="2"></li>
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        </div>
  
 +
        <!-- Wrapper for slides -->
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        <div class="carousel-inner">
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            <div class="item active">
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                <img src="https://static.igem.org/mediawiki/2017/1/1f/Npu-banner1.jpg">
  
 +
            </div>
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            <div class="item">
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                <img src="https://static.igem.org/mediawiki/2017/0/06/Npu-banner3.jpg">
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            </div>
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            <div class="item">
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                <img src="https://static.igem.org/mediawiki/2017/2/28/Npu-banner2.jpg">
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            </div>
 +
        </div>
 +
        <a class="left carousel-control" href="#myCarousel" data-slide="prev">
 +
            <span class="icon-prev"></span>
 +
        </a>
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        <a class="right carousel-control" href="#myCarousel" data-slide="next">
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            <span class="icon-next"></span>
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        </a>
 +
        <!-- Controls -->
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    </header>
  
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                    <h2 style="text-align:center">Introduction</h2>
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    <div class="batu" style="background: url('https://static.igem.org/mediawiki/2017/f/fe/Npu-background.png') no-repeat fixed; overflow: hidden;">
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        <!-- Page Content -->
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                    <h4>In the past 100 years, the rapid development of the traditional chemical industry has greatly promoted
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        <div class="container">
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                        the improvement of people’s material living standard. Our basic necessities of life are almost inseparable
+
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                        from the chemical synthesis goods. However, the environmental pollution and energy crises have also
+
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                        forced people to find new solutions. Synthetic biology instructs us that we can introduce new chemical
+
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                        reactions into biological cells, thus producing high quality chemical products in a greener way.</h4>
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                    <h3 style="text-align:center">Then what does synthetic biology "synthesize"?</h3>
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                    <img src="https://static.igem.org/mediawiki/2017/3/30/Zt.jpg" class="img-responsive">
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                    <h4>Biosynthesis of synthetic biology lies mainly in the biosynthesis of natural product and synthesis of
+
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                        bulk chemical. The former is represented by artemisinin, lycopene and carotene, etc., and the use
+
−
                        of synthetic biology method to synthesize our daily necessities of traditional chemical products
+
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                        or raw materials can serve more people. Today, scientists have been able to use micro-organisms or
+
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                        modified industrial enzymes to synthesize bio-plastics, bio-fuels, chemical raw materials and other
+
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                        chemical products.
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                        <br>
+
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                        <br>
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−
 
+
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+
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                        <br> For example, DuPont has achieved the reality of micro-algae efficiently synthesizing isobutanol;
+
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                        Blupha, a well-known company to Chinese iGEM teams, has also mastered the biosynthetic method to
+
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                        get PHA production. However, most of the existing products are facing the dilemma as for the cost,
+
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                        making them outshined by the traditional chemical products, which in fact limits the industrial promotion
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−
                        of synthetic biology.
+
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+
−
 
+
  
 +
            <div class="row" style=" padding-top:70px">
 +
                <div class="col-md-12">
 +
                    <h2 class="page-header" align="center" >Abstract</h2>
 +
                    <h4>Acrylic acid is a bulk chemical raw material, which is widely used in many fields because of its excellent
 +
                        polymerization capacity, such as paint, glue, and even mobile phone screen protective film. The average
 +
                        annual market demand of acrylic acid is up to 8 million tons, and the market value is nearly 10 billion
 +
                        US dollars. It has broad market prospect. At present, acrylic acid is made from propylene (which
 +
                        is obtained by petroleum cracking) after multi-step treatment. The production process causes pollution,
 +
                        high energy consumption and it is unsustainable.<br> This year, we aim to use a green and environmentally
 +
                        friendly carbon source, glycerol to achieve all green production of acrylic acid. Compared to traditional
 +
                        chemical synthesis methods, Synbio is green and sustainable, and glycerol is cheaper than ethylene.
 
                     </h4>
 
                     </h4>
 +
                 
 +
                </div>
 +
            </div>
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 +
            <!-- Marketing Icons Section -->
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            <div class="row" style="padding-top:70px">
 +
                <div class="col-md-12">
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                    <h2 class="page-header" align="center">We construct cell factory based on 4 levels, which are—</h2>
 +
                    <br>
 +
                </div>
 +
            </div>
  
  
−
                    <h2 style="text-align:center">Background
 
−
                    </h2>
 
  
−
                    <h4>This year, we focus mainly on an important synthetic organic chemical raw material——acrylic acid. We
 
−
                        hope to build efficient cell factories to achieve "all green" production of acrylic acid.</h4>
 
  
−
 
+
            <div class="row">
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                    <h3 style="text-align:center">What is acrylic acid?</h3>
+
                <div class="col-md-6 img-portfolio">
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                     <div align="center">
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                     <a href="portfolio-item.html">
−
 
+
                         <img class="img-responsive img-hover" src="https://static.igem.org/mediawiki/2017/a/ac/Ceas2.png">
−
                         <img src="https://static.igem.org/mediawiki/2017/b/bc/%E4%B8%99%E7%83%AF%E9%85%B8.png" class="img-responsive" width="50%" height="50%">
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                    </a>
−
                     </div>
+
                    <h3 align="center">
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                     <h4>Acrylic acid is an important synthetic organic chemical raw material. Acrylic acid and its ester compounds
+
                        <a href="portfolio-item.html">Core Part</a>
−
                         are widely used in adhesives, coatings, synthetic rubber, high absorbent resin and other chemical
+
                     </h3>
−
                         products.
+
                     <h4>We use ceaS2 enzyme as the core part, but acrylic acid is a byproduct of ceaS2 enzyme, the wild type
 +
                         's catalytic effect is very weak, whose production is only 1mg/L. So we hope to improve the catalytic
 +
                        effect of ceaS2 enzyme.<br> We designed ceaS2 enzyme mutants via the AEMD(Auto Enzyme Mutation Design)
 +
                        platform and screened for better-worked ceaS2 mutants by HPLC(High Performance Liquid Chromatography)
 +
                         and HTS(High throughput screening).
 
                     </h4>
 
                     </h4>
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                </div>
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                     <img src="https://static.igem.org/mediawiki/2017/a/a5/Zt2.jpg" class="img-responsive">
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                <div class="col-md-6 img-portfolio">
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                     <h3 style="text-align:center">The existing methods of producing acrylic acid
+
                     <a href="portfolio-item.html">
 +
                        <img class="img-responsive img-hover" src="https://static.igem.org/mediawiki/2017/8/85/System.png" alt="">
 +
                    </a>
 +
                     <h3 align="center">
 +
                        <a href="portfolio-item.html">System</a>
 
                     </h3>
 
                     </h3>
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+
                     <h4>Respectively, E. coli and S. cerevisiae are the two sorts of model organisms that are most convenient
−
                     <h4>According to our current research carried out about the acrylic acid synthesis method, we list them as
+
                         to operate in the prokaryote and eukaryote. Therefore, in terms of our choice of the chassis organisms,
−
                        follows:
+
                         we have them both tested, which were E. coli MG1655 and S. cerevisiae BY4741 individually.
−
                        <br> 1.Traditional chemical synthesis
+
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+
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                                    <h4 class="panel-title">
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                                        <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion" href="#collapseOne">
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                                            Acrylic acid two-step oxidation
+
−
                                        </a>
+
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                                    </h4>
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                                        The first step of two-step oxidation of acrylic acid is propylene reacts with oxygen, producing acrolein. And then, acrolein
+
−
                                        reacts with oxygen, producing acrylic acid. The conversion rate is up to 90%. Chemical
+
−
                                        Formula (1) and (2) are showed below. This method is widely used in industry production
+
−
                                        of acrylic acid.
+
−
                                        <br>
+
−
                                        <br>H2C=CH-CH3+3/2O2→H2C=CH-CHO+H2O(1)
+
−
 
+
−
                                        <br> H2C=CH-CHO+ 1/2O2→H2C=CH-COOH(2)
+
−
                                        <br>
+
−
                                        <br> The process of the oxidation method of the propylene is mentioned in the patent
+
−
                                        of the Japanese Catalyst Company in the 1880s. The reaction temperature of the first
+
−
                                        step is 320-330℃. If other additives such as W, Co, K, Si and O are added to the
+
−
                                        catalyst MoBiFe, the yield of acrolein can reach more than 90% [4]. The reaction
+
−
                                        temperature of the second step is 210-255 ℃. The compositions of the catalyst are
+
−
                                        Mo, Bi, Fe, Co, K and O. The yield of acrylic acid can reach 97.5% [4]. The yield
+
−
                                        of acrylic acid in the two-step oxidation process is much higher than that of the
+
−
                                        direct oxidation of propylene to produce acrylic acid. This is because the reaction
+
−
                                        temperature in the one-step process is 325-350 ° C, at which the conversion of propylene
+
−
                                        to acrolein is high. But acrolein and acrylic acid are further oxidized at that temperature
+
−
                                        [4]. Therefore, to obtain higher yields of acrylic acid, control the reaction at
+
−
                                        different stages by controlling the temperature and changing the catalyst composition
+
−
                                        in the two-step method is more reasonable and more valuable. As the most widely used
+
−
                                        method in the industrial production of acrylic acid, oxidation of propylene has the
+
−
                                        advantages: high conversion efficiency and simple production process.
+
−
 
+
−
                                    </div>
+
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                                </div>
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                            </div>
+
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                         </div>
+
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+
−
 
+
−
 
+
−
 
+
−
                        <br> Propylene firstly reacts with oxygen to produce acrolein, whose deoxidation leads to the production
+
−
                        of acrylic acid. The conversion rate is often up to 90%, so this method is applied in most industrial
+
−
                        production of acrylic acid
+
−
                        <br> Although this practice has many advantages, but the raw material depends heavily on the traditional
+
−
                        fossil energy, bringing about heavy pollution, high energy consumption and a lack of sustainability.
+
−
                        Therefore, it is imperative to develop renewable energy alternative to replace fossil energy to produce
+
−
                        acrylic acid in a greener way.
+
−
                        <br> 2.Acrylic acid semi-biosynthesis
+
−
                        <br> Acrylic acid semi-biosynthesis refers to the method of using micro-organisms to turn acrylonitrile,
+
−
                        acrylamide and other petrochemical raw materials into acrylic acid.
+
−
 
+
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                                        <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion" href="#collapseTwo">
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                                            Acrylonitrile conversion
+
−
                                        </a>
+
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                                    </h4>
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                                        So far, the researchers have found that certain microorganisms which contain nitrilase can catalyze the conversion of acrylonitrile
+
−
                                        to acrylic acid. Nitrilase can catalyze the nitrile compound directly to produce
+
−
                                        the corresponding products of carboxylic acid [5]. Nitrilases are present in Rhodococcus,
+
−
                                        Pseudomonas, Nocardia and Bacillus [6].
+
−
                                        <br>
+
−
                                        <br>There are many advantages of Hydrolysis of Acrylonitrile to produce acrylic acid,
+
−
                                        for example, specificity of nitrilases, high conversion rate of acrylonitrile, the
+
−
                                        moderate reaction conditions, and less by-products. However, acrylonitrile is a chemical
+
−
                                        product comes from fossils, and the price is higher than acrylic acid, so it is not
+
−
                                        suitable for the needs of sustainable development and does not meet the long-term
+
−
                                        development of society.
+
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                                    </div>
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                                </div>
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                                            Acrylamide conversion
+
−
                                        </a>
+
−
                                    </h4>
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                                        Acrylamide also relies on petrochemical resources to obtain the product. According to current report, Rhodococcus (Rhodococcus
+
−
                                        AJ270), Pseudomonas aeruginosa, Bacillus thuringiensis BR449 and other microorganisms
+
−
                                        can catalyze the conversion of acrylamide to acrylic acid[10]. Acrylamide is converted
+
−
                                        to acrylic acid by amidase. Rhodococcus AJ270 can grow with acetamide as a carbon
+
−
                                        source and show high amidase activity during metabolism. The conversion of acrylamide
+
−
                                        has the advantages of moderate reaction conditions, high conversion rate, long reaction
+
−
                                        time and large yield, but it has the same shortcomings as the conversion of acrylonitrile.
+
−
                                        Rhodococcus AJ270 needs amidase as raw material to express acetamide, and the price
+
−
                                        of acetamide and acrylamide is high, thus limiting the industrial production using
+
−
                                        this method.
+
−
                                    </div>
+
−
                                </div>
+
−
                            </div>
+
−
                         </div>
+
−
 
+
−
 
+
−
 
+
−
                        <br>Acrylic acid semi-biological method, although possesses the high yield, its raw materials acrylonitrile
+
−
                        and acrylamide cost even more than acrylic acid, which limits the industrialization of this method.
+
−
                        <br> 3.Acrylic acid complete biosynthesis
+
−
                        <br> Acrylic acid complete biosynthesis method refers to the direct use of saccharides and other biomass
+
−
                        fermentation to produce acrylic acid.
+
−
 
+
−
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                                            Lactate dehydration pathway
+
−
                                        </a>
+
−
                                    </h4>
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                                        Just as its name implies, lactic acid dehydration pathway refers to a metabolic pathway using the dehydration of lactic acid
+
−
                                        to produce acrylic acid. Because the fermentation production process of lactic acid
+
−
                                        is very mature, so using the dehydration of lactic acid to produce acrylic acid has
+
−
                                        long been aroused the interest of the researchers.
+
−
                                        <br>
+
−
                                        <br>At present, the method mainly uses Clostridium propionicum as the starting strain.
+
−
                                        Specific metabolic pathway is shown in Figure 1.2 [14]. Although the route is short,
+
−
                                        but there are still many problems when used in producing acrylic acid.
+
−
                                        <br>
+
−
                                        <br>As can be seen from Figure 1.2, metabolism of lactic acid is divided into the left
+
−
                                        side, the oxidation pathway and the right side, the reduction pathway. When Clostridium
+
−
                                        propionate uses lactic acid as a source of energy, one molecule of lactic acid produces
+
−
                                        one third of the molecule of acetic acid and 2/3 of the propionic acid [15]. In the
+
−
                                        production process of acetic acid, there will be four electrons and 4 protons generate,
+
−
                                        as well as offering ATP for bacteria to grow. The acryloyl CoA in the reduction pathway
+
−
                                        receives electrons to produce propionyl CoA and finally generates propionic acid.
+
−
                                        <div align="center">
+
−
                                            <img src="https://static.igem.org/mediawiki/2017/7/7f/Lactate_dehydration_pathway.png" class="img-responsive" width="50%" height="50%"
+
−
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+
−
                                        </div>
+
−
 
+
−
 
+
−
                                    </div>
+
−
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+
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                                        <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion" href="#collapse6">
+
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                                            3-hydroxypropionic acid pathway
+
−
                                        </a>
+
−
                                    </h4>
+
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                                </div>
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−
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                                    <div class="panel-body">
+
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                                        3-hydroxy propionic acid (3-HP) is an important chemical intermediate, there are a number of patents have reported the methods
+
−
                                        of sugar conversion to 3-HP [20-22]. And 3-HP has two functional groups, carboxyl
+
−
                                        and hydroxyl. It is possible to synthesize a variety of important chemical substances
+
−
                                        such as 1,3-propanediol, succinic acid through oxidation, dehydration and esterification
+
−
                                        reaction,. Using 3-HP to develop downstream products, such as acrylic acid is also
+
−
                                        one of the hot spots.
+
−
                                        <div align="center">
+
−
                                            <img src="https://static.igem.org/mediawiki/2017/f/fb/3-hydroxypropionic_acid_pathway.png" class="img-responsive" width="50%" height="50%"
+
−
                                                style="padding-top:20px">
+
−
                                        </div>
+
−
 
+
−
 
+
−
                                        <br> Using 3-hydroxypropionic acid-related pathways to construct engineering bacteria
+
−
                                        to produce acrylic acid is a hotspot in recent years [30-33], but the yield is generally
+
−
                                        not high, partly because of the toxic side effects of acrylic acid on cells and,
+
−
                                        on the other hand, the pathway is long, and the reaction requires vitamin B12 to
+
−
                                        participate in, it is very difficult to achieve high yield of acrylic acid with this
+
−
                                        approach.
+
−
                                    </div>
+
−
                                </div>
+
−
                            </div>
+
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+
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                                        <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion" href="#collapse4">
+
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                                            Propionic acid oxidation pathway
+
−
                                        </a>
+
−
                                    </h4>
+
−
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+
−
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+
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                                        Propionic acid oxidation pathway refers to Clostridium propionate use propionic acid as a substrate to produce acrylic acid
+
−
                                        under the aerobic conditions. It is speculated that Propionic acid oxidation pathway
+
−
                                        is the reverse pathways from lactic acid to propionic acid in Clostridium propionate,
+
−
                                        namely propionic acid to propionyl CoA, and then to acryloyl CoA , finally converted
+
−
                                        to acrylic acid. Propionic acid oxidation pathway has the same problem as lactate
+
−
                                        dehydration pathways, that is, need to add exogenous electron acceptor to achieve
+
−
                                        coenzyme regeneration, so that the entire cell system remained stable.
+
−
                                    </div>
+
−
                                </div>
+
−
                            </div>
+
−
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+
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+
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                                        <a class="accordion-toggle" data-toggle="collapse" data-parent="#accordion" href="#collapse5">
+
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                                            DMSP pathway
+
−
                                        </a>
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                                        Dimethylsulphoniopropionate (DMSP) is a sulfur metabolite synthesized in some higher plants in sea water, algae and marine
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                                        microalgae [36]. Some marine organisms such as bacteria, phytoplankton have DMSP
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                                        lyase, which cleaves the DMSP into acrylate and dimethyl sulfide (DMS) [37], which
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                                        is also commonly found in Alcaligines faecalis, The route is shown in Figure 1.3.
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                                        Extracellular DMSP is transported into the body by the carrier protein, be cleaved
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                                        into acrylic acid and DMS by DMSP lyase. Acrylic acid is further reacted to form
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                                        β-HP.
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                                        <br>The DMSP pathway is the only biological pathway that can directly produce acrylic
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                                        acid. The DMSP lyase is the key enzymes, but it is not clear at present that there
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                                        is no definite sequence of its genes. Therefore, research report about making use
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                                        of or modifying DMSP pathway is rarely seen.
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                        <br> Some shortcomings of the existing acrylic acid biosynthesis method include complexity of the synthetic
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                        pathway , obscuration of the synthesis mechanism and low efficiency of the synthesis. How to build
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                        a short and efficient acrylic acid biosynthetic pathway to achieve a highly efficient acrylic biosynthetic
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                        factory is the very key to success! And this is also the entry point of our project this year.
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                        <br>
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                    <h3 style="text-align:center">Why we choose Glycerol as cabon source？</h3>
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                    <h4>Glycerol is a simple polyol compound, which presents as viscous liquid at the room temperature. It is
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                         colorless, tasteless and non-toxic. Glycerol is a by-product of the biodiesel manufacturing industry,
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                         which once was a relatively scarce chemical raw material. With the rapid development of bio-diesel
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                         manufacturing industry in recent years, the substantial increase of glycerol production has led to
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                         the significantly lower price. Therefore, the use of glycerol as a raw material for microbial cell
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                         <img class="img-responsive img-hover" src="https://static.igem.org/mediawiki/2017/e/ec/Pathway.png" alt="">
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                         factory to produce bulk chemicals has the advantage of being cheap and green, while it also allays
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                         the pressure of dealing with the by-products waste in the production of biodiesel. In addition, compared
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                         with glucose, xylose and other carbohydrate substrates, glycerol metabolism can produce higher reducing
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                         power, making it the ideal carbon source for the fermentation synthesis in cell factory.
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                    <h4>We need to design two different metabolic pathways for two different chassis organisms and propose different
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                         optimization schemes for them.We introduced the ceaS2 enzyme exogenously on the basis of the glycerol
 +
                         metabolism of the two bacteria, so that it could produce the target product acrylic acid using the
 +
                         intermediates G3P and DHAP.Besides having finished the construction of the pathways, we also reconstructed
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                         and optimized the original metabolic pathway to increase the carbon flux rate of the designed pathway
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                        and reduce the loss of bypass carbon flux.</h4>
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                        <a href="portfolio-item.html" >Production</a>
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                    <h4>All of the previous processes are to build the engineering strains which have a high production of acrylic
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                        acid that we need. In the subsequent fermentation, we also need to determine the best parameters
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                         of the engineering strain.<br> Therefore, we selected the carbon source, Buffer, temperature, pH
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                         and other conditions to optimize the cell production process.</h4>
 
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Revision as of 08:06, 28 October 2017

Abstract

Acrylic acid is a bulk chemical raw material, which is widely used in many fields because of its excellent polymerization capacity, such as paint, glue, and even mobile phone screen protective film. The average annual market demand of acrylic acid is up to 8 million tons, and the market value is nearly 10 billion US dollars. It has broad market prospect. At present, acrylic acid is made from propylene (which is obtained by petroleum cracking) after multi-step treatment. The production process causes pollution, high energy consumption and it is unsustainable.
This year, we aim to use a green and environmentally friendly carbon source, glycerol to achieve all green production of acrylic acid. Compared to traditional chemical synthesis methods, Synbio is green and sustainable, and glycerol is cheaper than ethylene.

We construct cell factory based on 4 levels, which are—


Core Part

We use ceaS2 enzyme as the core part, but acrylic acid is a byproduct of ceaS2 enzyme, the wild type 's catalytic effect is very weak, whose production is only 1mg/L. So we hope to improve the catalytic effect of ceaS2 enzyme.
We designed ceaS2 enzyme mutants via the AEMD(Auto Enzyme Mutation Design) platform and screened for better-worked ceaS2 mutants by HPLC(High Performance Liquid Chromatography) and HTS(High throughput screening).

System

Respectively, E. coli and S. cerevisiae are the two sorts of model organisms that are most convenient to operate in the prokaryote and eukaryote. Therefore, in terms of our choice of the chassis organisms, we have them both tested, which were E. coli MG1655 and S. cerevisiae BY4741 individually.

Pathway

We need to design two different metabolic pathways for two different chassis organisms and propose different optimization schemes for them.We introduced the ceaS2 enzyme exogenously on the basis of the glycerol metabolism of the two bacteria, so that it could produce the target product acrylic acid using the intermediates G3P and DHAP.Besides having finished the construction of the pathways, we also reconstructed and optimized the original metabolic pathway to increase the carbon flux rate of the designed pathway and reduce the loss of bypass carbon flux.

Production

All of the previous processes are to build the engineering strains which have a high production of acrylic acid that we need. In the subsequent fermentation, we also need to determine the best parameters of the engineering strain.
Therefore, we selected the carbon source, Buffer, temperature, pH and other conditions to optimize the cell production process.