Biocatalytic Formation of Industrial Nitriles from Biomass

Introduction of functionality into hydrocarbons to produce functional chemicals is energy intensive. This is especially true for nitrogen containing chemicals where ammonia is used. Research is focusing on the transformation of amino acids from protein-rich waste streams into bulk chemicals, one example is glutamic acid (Glu) – a versatile starting material for the syntheses of N-succinonitrile and acrylonitrile via 3-cyanopropanoic acid (CPA). CPA can be chemically produced using NaBr and excess NaOCl, however, salt formation and the need to cool the reaction have undesirable economic and ecological effects. A more viable conversion of Glu to CPA is via enzymatic oxidative decarboxylation using HOBr produced by vanadium chloroperoxidase (VCPO) from H2O2 and NaBr.

Highlight of the past year

In the first part of the year, the role of halides and their concentration was explored on amino acids with different functionalities and the consequences of this on conversion and selectivity.

It was found that the conversion and selectivity can be modified as a function of NaBr concentration but not as a function of halide type. Based on this the influence of the side chain length and functionality were studied. It was found that there is an optimum length – 5 carbons – where most amino acids gave very high selectivity. Moreover, the functionality present on the side chain that give the best results towards the nitrile formation is the carboxylic functionality. It was hypothesized that subtle interactions between the acidic amino acids and the halide salt change the conformation of amino acid in solution.    

Type of student projects envisioned

The typical work within this project involves lab experiments (enzymatic reactions) and analytical studies (spectrometry, HPLC, others).