Yield10 Bioscience (United States)

Crotonic acid has the potential to be produced from renewable resources at low cost but currently has a limited market. We are investigating catalytic routes to exploit the functionalities of crotonic acid to produce a range of established industrial chemicals. Here we report our work on converting crotonates to acrylates, where a cost-competitive bio-based alternative can provide a market advantage. Our optimized reaction conditions for the cross-metathesis between crotonates and ethylene resulted in an increase in catalyst turnover numbers by 2 orders of magnitude compared with literature values. Control experiments showed the cross-metathesis with ethylene to be an equilibrium reaction. The turnover-number-limiting factor was found to be the stability of the metathesis catalyst.

A second promoter (P1) was inserted to the PHA (poly-β-hydroxyalkanoate) operon (pSP2) of Esherichia coli DH5α with an optimal E. coli ribosome binding site and a trc strong promoter (pSJS1) to obtain poly-β-hydroxybutyrate (PHB) with long chain length. When the inducer, IPTG was added to the culture at 0.4 mM, the average molecular weight was 1.1 × 106 Da. However, an even greater increase of the PHB average molecular weight to 2.5 × 107 Da was observed without IPTG being added.