Eight kinds of enzymes "one-pot" catalyzed efficient and green synthesis of nylon monomers

Nylon is a very widely used synthetic fiber, there are many kinds of nylon, of which nylon 66 is the most important one

The team of Professor Li Aitao of the State Key Laboratory of Biocatalysis and Enzyme Engineering jointly established by the School of Life Sciences of Hubei University and the provincial and ministerial departments has designed a new artificial biosynthesis pathway.

Chemical synthesis of nylon monomer, the pollution of the environment is restricted

Nylon, commonly known as polyamide, is the first synthetic fiber to appear in the world.

There are many kinds of nylon, which can be divided into aliphatic, aromatic and aliphatic-aromatic nylon according to the structure of the monomer.

"Nylon 66 is prepared by the condensation of adipic acid and hexamethylene diamine, and adipic acid is the main monomer, and its synthesis mainly relies on a multi-step chemical oxidation process with high pollution and high energy consumption

In response to the above problems, in recent decades, scientists have been exploring new efficient and green synthesis methods and processes for such nylon monomers

Efficient and green synthesis of nylon monomers catalyzed by cheap enzymes

With the development of synthetic biotechnology, the artificially designed multi-enzyme cascade catalysis can put a variety of enzyme catalysts with different catalytic activities in the same reaction system, under mild and environmentally friendly conditions, cheap and easily available raw materials , synthesizing high value-added products for human needs through a one-pot multi-step method

In addition, if cells expressing multiple enzymes are directly used as catalysts to catalyze the target reaction in vivo, the separation and purification of enzymes and the addition of expensive coenzymes can be avoided, thereby greatly reducing production costs

The application of this method to the synthesis of adipic acid is expected to solve the problems that have plagued the scientific and industrial circles for decades

In order to achieve the above goals, Li Aitao's team designed a biosynthetic pathway containing 8 enzymes from scratch, hoping to convert cyclohexane to adipic acid through cascade catalysis in the same reaction system

Next, the researchers tried to express 8 enzymes in the same cell to construct a cell catalyst, and found that due to the heavy burden on the cell, the expression of some enzymes in the cell was very low, resulting in poor catalytic efficiency of the entire reaction

The process catalyzes the reaction under mild conditions (normal temperature, normal pressure and aqueous phase), uses self-sufficient coenzyme self-circulation, does not require any exogenous expensive coenzyme, and has low cost

In addition, by arbitrarily assembling the three cellular catalysts through a "plug-and-play" strategy, adipic acid products can be synthesized from an intermediate product in a certain link in the pathway through catalytic conversion