NHase expression in Corynebacterium glutamicum

Industrial scale biocatalytic production of acrylamide relies on the use of engineered strains of Rhodococcus. There is a newly accepted manuscript in Applied Microbiology and Biotechnology from three Korean groups lead by J-H Lee and H-S Kim where the NHase from a Rhodococcus strain is expressed in Corynebacterium glutamicum (a cell factory already used commercially in amino acid biosynthesis) and tested for its ability to hydrate acrylonitrile. Whilst it didnt have the same activity as the NHase in the homologous system, the advantage the authors propose is that the rate of growth and hence enzyme production is higher with C. glutamicum.

 

Sol-gel encapsulation of Cobalt centred nitrile hydratase

The nitrile hydratase from Pseudonocardia thermophila is one of the most stable NHases currently described. It is cobalt centred, and one strain of it has an entry in the PDB. Holz and co-workers have just published a paper entitled "Acrylamide Production using Encapsulated Nitrile Hydratase from Pseudonocardia thermophila in a Sol-gel matrix" in the Journal of Molecular Catalysis A. They show that their system is able to convert acrylonitrile to acrylamide neatly, demonstrating the advantages of their enzyme support system in terms of increasing the robustness of these still rather sensitive enzymes. Interesting to me is that their orthosilicate sol-gels boost this enzyme's stability in methanol to take as much as a70% v/v mix happily.

A new review: Industrial Biotechnology- the future of green chemistry

The most recent issue of Green Chemistry has a 41 page review (DOI: 10.1039/C1GC15579B) by Udo Kragl and his co-workers Stefanie Wenda, Sabine Illner and Annett Mell, entitled  "Industrial Biotechnology- the future for green chemistry" which is a useful overview of where biocatalysis is now. A nice feature it has that I havent seen before is the use of little boxes which are labelled "critical remarks" to discuss highlight problems sometimes in the perception and sometimes in the reality of using biocatalytic process industrially.
As is necessary in this sort of review, there is a discussion (p. 3011) on how good nitrile hydratase is for bulk synthesis of acrylamide though it is interesting to see the scale of the use is "more than 50,000 tons per year" referring back to a viewpoint paper in ChemCatChem authored by Yuryev and Liese which actually says the Mitsubishi Rayon process "runs on scales up to 50,000 tons per year"- whatever that actually means! So it would appear that my suspicion that no one actually knows how successful (in terms of level of adoption) one of the most successfully implemented biocatalytic processes is, has not been contradicted!
Directly following the discussion of acrylamide manufacture is a discussion comparing the chemical and the Lonza chemoenzymatic routes to nicotinamide, with some excellent leading references.