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Team:Uppsala-Sweden/Butanol
From 2009.igem.org
Contents |
The Butanol Approach
Our goal is to achieve photosynthetic production of butanol and its derivates with the cyanobacterium Synechocystis sp. PCC 6803 as the final host organism.
Background
Cyanobacteria have the capability to harvest the energy from the sun and convert it into other forms of energy. The natural way for these organisms is to store it as sugars or other carbohydrates in a way similar to plants. By introducing a casette of genes for isobutanol production, we would like to derive a cyanobacteria that produces butanol and its derivates.
The Pathway
The original pathway to obtain branched-chain higher alcohols was proposed and succesfully established in E. coli by Shota Atsumi, Taizo Hanai and James C. Liao from the University of Californa, Los Angeles [1]. As we expect a broad range of higher alcohols, we will exemplarily demonstrate the biochemical mechanism at the pathway of isobutanol, the product we expect to be the most occuring one.
The precursor for butanol production is pyruvate, a central metabolite which is usually derived by the glycolisis, which is further processed to amino acid precursors. First 2 pyruvate molecules are converted to 2-acetolactate and subsequently to 2,3-dihydroxy-isovalerate. A dehydration reaction results in our first molecule of interest, 2-ketoisovalerate, which is a precursor for the synthesis of valine, alanine and leucine aminoacids.[2]
So far only host enzymes were used and now it's time to introduce our first BioBrick , the codon-optimized version of the a-ketoisovalerate decarboxylase (kivd) from Lactococcus lactis ssp. lactis
The Construct
Here is the preliminary construct for Synechocystis 6803.
