Japanese scientists find use metabalic engineering to boost biochemicals

“It is hoped that using biomass to produce various useful compounds can form a basis for a low-carbon society, reducing the amount of atmospheric CO₂.”

A Japanese group of scientists has found a new way of using microbes to improve the yield of chemical compounds extracted from lignocellulosic biomass.

The research group consisted of doctoral student Fujiwara Ryosuke, Associate Professor Tanaka Tsutomu (both of Kobe University’s Graduate School of Engineering) and Research Scientist Noda Shuhei (RIKEN Center for Sustainable Resource Science).

They achieved their objectives “through metabolically engineering the bacteria used in bioproduction, so that it would use different kinds of sugar absorbed from the biomass for separate aims”.

There are problems encountered when using microbes to produce target chemicals; if the microbes use the carbon sources (sugars) for their own propagation, target chemical production decreases, the scientists said.

On the other hand, suppressing this propagation causes the microbes to weaken, resulting in an overall decline in production. To try to solve this issue, 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 utilise 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.

The results of this research were first published in Nature Communications on January 14.

Industry relies on fossil fuels as raw materials for producing various products. However, producing petroleum-derived compounds increases the amount of atmospheric CO₂, causing a multitude of environmental problems.

Consequently, there is a need to develop biorefinery technologies that involve using microbes to produce chemical compounds from naturally abundant renewable resources such as tree and plant matter. Biomass-derived products have the advantage of being carbon neutral; they do not increase the amount of CO₂ in the atmosphere. It is hoped that using biomass to produce various useful compounds can form a basis for a low-carbon society, reducing the amount of atmospheric CO₂.

Muconic acid is a useful chemical that can be easily converted into adipic acid, an ingredient in nylon production. It is also used as a raw material in the production of medical and chemical products. However, it is currently chemically synthesized from petroleum resources.

The scientists said: “It is hoped that a fermentation method could be developed using microbes and renewable plant-based resources with milder reaction conditions and fewer by-products.

“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 utilised.”

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