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Bioengineering Seminar |
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| Category: | College of Engineering - BNG |
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| Date & Time: |
Tuesday , 10/02/2012 from 12:30 AM to 01:45 AM |
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| Location: | Textiles 102 | |
| Admission: | Free! | |
| Contact: |
Qinguo Fan qinguo.fan@umassd.edu 508-999-9147 |
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| Description: |
Title: Bioplastics and biofuels production in wild-type and engineered Ralstonia eutropha Speaker: Dr. Christopher Brigham, Biology Department, MIT Abstract: Ralstonia eutropha, a Gram negative betaproteobacterium commonly found in soils, utilizes a wide variety of carbon sources for growth and survival. It is most well studied for its ability to synthesize intracellular polyhydroxyalkanoate (PHA), which is a family of polyesters that is being touted as a potential bio-based, biodegradable replacement for petroleum-based plastics. PHA synthesis is advantageous for the bacterium as a means of carbon and energy storage and also as a means of surviving stress conditions. We have examined the dynamics of the PHA cycle in R. eutropha to determine the cellular changes that occur when the organism makes and/or breaks down the polymer. We have engineered strains that produce PHA with improved monomer contents, in order to produce a polymer with more favorable thermoplastic properties. In addition, process engineering has allowed us to achieve high cell density in fermentations using a variety of different carbon sources to make different types of PHA. The goal is to decrease the production costs of the bioplastic to make it a cost competitive alternative to current polymers on the market. Ideally, PHA would be produced by R. eutropha strains using naturally available (unrefined) carbon substrates or carbon found in agricultural and food processing waste streams. We have also sought to manipulate the flow of carbon in R. eutropha to produce bio-based fuel molecules and have recently engineered a strain to produce isobutanol, a short chain biofuel, instead of PHA. Isobutanol, as a biofuel, has a higher energy density that ethanol, and can be used in existing automobile engines with no major modifications. We have manipulated the branched-chain amino acid pathway of the organism to produce isobutanol from fructose or organic acids as carbon sources. Using strain engineering techniques, we have significantly increased the output of isobutanol from the current production strain. |
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| Additional Info: | Teaching a microbe to make fuel | |
