TAGS: Biobased Solutions
A research group from Kobe University and RIKEN Center for Sustainable Resource Science has succeeded in improving the yield of target chemical production from biomass. They achieved this through metabolically engineering the bacteria used in bioproduction, so that it would use different kinds of sugar absorbed from the biomass for separate aims.
The Parallel Metabolic Pathway Engineering (PMPE) Strategy
The research team developed a new strategy called Parallel Metabolic Pathway Engineering (PMPE), allowing them to control both target chemical production and microbe propagation. They used this approach to alter E. coli bacteria in order to successfully boost the production of the nylon precursor muconic acid.
If it becomes possible to utilize the selected carbon source solely for target chemical production and use the remaining sources for microbe propagation, this will bring about great advances in the production of aromatic compounds and raw materials for medical and chemical products.
Development of the PMPE strategy which allows the utilization of sugars for microbe propagation and target chemical production to be independently controlled. Using this approach, the research group successfully increased the yield of muconic acid (the target chemical).
PMPE can be applied to the production of various raw materials, such as aromatic compounds and dicarboxylic acid, utilized in chemical products and medicines.
Expected to improve the effective utilization of raw materials, such as biomass, which contain multiple sugars.
Modifying E. coli for Target Chemical Production
Lignocellulosic biomass, which does not compete with global food supplies, is made up of glucose and xylose sugars. The research team developed a metabolic strategy which involved modifying the E. coli bacteria so that it would utilize glucose for target chemical production and xylose for microbe propagation.
In regular microbes, glucose and xylose use the same metabolic pathway and are both utilized for microbe growth and target chemical production. This reduces the amount of target chemical synthesized because the microbes absorb the sugars to produce and maintain the elements and energy that they require to live.
To mitigate this issue, the research group developed a new strategy called PMPE. Dividing the microbes’ metabolic pathway allows each sugar to be utilized independently with all the glucose being used for target chemical production and all the xylose being used for microbe propagation and maintenance. This allowed a greater yield of the target chemical to be produced because none of the glucose was being utilized for microbe growth.
This research group introduced a metabolic pathway to the modified E. coli for synthesizing muconic acid. The modified E. coli utilized the glucose and xylose, leading to the production of the target chemical. The researchers succeeded in producing 4.26 g/L of muconic acid with a yield of 0.31g/g-glucose. This is considered the highest yield in the world, proving the effectiveness of the PMPE strategy.
Versatile Technique to Efficiently Produce Different Compounds
Subsequently, the researchers investigated whether the PMPE strategy could be applied to the production of target chemicals other than muconic acid. As a result, they successfully increased yields of the essential amino acid and aromatic compound phenylalanine, and 1,2- propanediol, which is used as an additive in medicines and food products. These results have shown that PMPE is a versatile technique that can be used to efficiently produce a variety of compounds.
It is expected that the PMPE technique developed by this research group can be applied to increase the production of wide variety of raw materials, such as aromatic compounds and dicarboxylic acid, used in medical and chemical products. Furthermore, this strategy of altering the bacteria’s metabolism will allow biomass containing multiple sugars to be more efficiently utilized.
Source: Kobe University