**PROBLEM:** Adipic acid (ADP; aka hexanedioic acid) is an important chemical. It is used for manufacturing many common materials including polyurethanes, plasticisers used in PVC production, and Nylon 6,6 (which consumes ~75% of all ADP made).

ADP is manufactured via a multi-step reaction:

* Benzene is reduced to cyclohexane at high-pressures and high temperatures using a catalyst (e.g., Ni/Al2O3) and a hydrogen feed.
* Cyclohexane is oxidized using air plus a metal catalyst (e.g., cobalt) to generate a cyclohexanone and cyclohexanol mixture (KA oil).
* KA oil is oxidized with nitric oxide and copper/ammonium metavanadate to produce ADP \[conversion yield ~95%\].

Industrial ADP manufacturing causes significant environmental problems:

* Around 10% of global nitric oxide (NOx) emissions are from ADP production.
* The benzene feedstock is a non-renewable petroleum compound and volatile carcinogen.
* Spent metal catalysts create toxic waste streams.

**OPPORTUNITY:** Mellizyme are engineering a novel enzyme 'MP1' and have recently identified that it exhibits activity that enables the conversion of cyclohexane to ADP in air, enabling a greener ADP manufacturing method.

**KEY PROJECT OBJECTIVES:** Deploy synthetic biology approaches to engineer MP1 to increase its thermostability, conversion rate speed, and diminish the formation of unwanted by-products. The project outputs will help Mellizyme to plan a future collaborative industrial demonstrator project showing how MP1 can be used at-scale for industrial ADP manufacturing.

**STATE-OF-THE-ART LIMITATIONS**

* Chemosynthetic methods of ADP manufacture suffer low conversion rates of cyclohexane and selectivity issues, leading to the formation of diacid contaminants, posing purification problems.
* Catalytic degradation of NOx requires additional capital and energy expenditures.
* Biomass-derived routes frequently require expensive precious metal catalysts.

**MP1 INNOVATIONS/USPs**

* MP1 works at atmospheric pressure and at a lower temperature than existing methods. This significantly reduces the energy requirement for ADP manufacturing using MP1 when compared to the high-pressures and high temperatures needed for the usual routes by which ADP is manufactured.
* MP1 removes the need for metal catalysts, preserving rare metals, and stopping toxic metal waste formation.
* Zero NOx production, supporting net zero targets.