Breakthrough Study Reveals Sustainable Path to Produce Nylon 12 from Biomass Sugars

A recent study from the Shenzhen Institute of Advanced Technology at the Chinese Academy of Sciences has unveiled a revolutionary method for synthesizing 12-aminododecanoic acid (ADDA), a key monomer for producing nylon 12, from biomass sugars. This advancement addresses significant challenges in the current nylon production process, which relies heavily on petroleum and is fraught with environmental concerns.

With a global market exceeding 100 billion yuan, nylon 12 is crucial across various industries, including automotive, electronics, and medical applications. However, the synthesis of nylon 12 has long been dominated by a few companies, posing supply risks for manufacturers. Furthermore, the traditional production methods cause considerable environmental pollution, underscoring the urgent need for greener alternatives.

The research, published in the journal Metabolic Engineering, identifies two major technical bottlenecks in ADDA biosynthesis: the toxicity of the intermediate dodecanoic acid (DDA) to host cells and the accumulation of dodecanedioic acid (DDDA), a byproduct that reduces yield and increases production costs. The study effectively elucidates the mechanisms behind these issues and introduces high-yield bacterial strains.

To tackle DDA's toxicity, the study employs a quorum sensing expression (QSE) system, allowing for lower UcfatB enzyme expression levels during early growth stages, thereby minimizing cell toxicity while still accumulating DDA. The approach enhances DDA yields without inducing harmful effects on the cells.

In addressing DDDA accumulation, the researchers successfully knocked out 16 aldehyde dehydrogenases and reductases in E. coli, effectively reducing DDDA levels during the conversion of DDA to ADDA. This strategic modification significantly improved the overall production process.

The study demonstrated successful conversion of both glucose and cellobiose into ADDA, achieving a remarkable 509 mg/L yield under cellobiose conditions and 1035 mg/L in a 15-liter fermentation setup, with a conversion rate of 5% and no detectable DDDA accumulation.

This innovative one-step fermentation process not only achieves the highest yield of ADDA from sugars to date but also paves the way for more sustainable production of nylon 12 and other polyamides. The research was led by master’s graduate Gao Haixin and research assistant Fang Qiang, with professor Howard H. Chou serving as the corresponding author. The study received support from major funding initiatives including the National Key Research and Development Program and the National Natural Science Foundation of China.

This breakthrough offers a promising pathway to revolutionize the nylon industry, emphasizing the importance of sustainable practices in chemical manufacturing.