Acrylamide Rhodococcus rhodochrous

Nagasawa, T., Shimizu, H. and Yamada, H. (1993) The superiority of the third-generation catalyst, Rhodococcus rhodochrous J1 nitrile hydratase, for industrial production of acrylamide. AppliedMircobiology and Biotechnology, 40, 189-195. 

Acrylonitrile produced industrially via propylene ammoxidation contains trace amounts of benzene. When using Pseudonocardia thermophila JCM3095 or Rhodococcus rhodochrous J-1 as microbial NHase catalyst for conversion of acrylonitrile to acrylamide, concentrations of benzene of <4 ppm produced a significant increase in the reaction rate [16]. Maintaining the concentration of HCN and oxazole at <5 ppm and <10 ppm respectively produced high-quality acrylamide suitable for polymerization. 

While the production of acrylamide by NHase is a well-established industrial process, only a first report exists for the production of butyramide from butyronitrile. Using Rhodococcus rhodochrous PA-34 (at a loading of 1 g dew), 595 g butyramide was prepared in quantitative yield from 60% (v/v) butyronitrile in a pH 7.0, 1 L batch reaction, at 10 °C [18]. 

One of the best examples for discussing biotransformations in neat solvents is the enzymatic hydrolysis of acrylonitrile, a solvent, to acrylamide, covered in Chapter 7, Section 7.1.1.1. For several applications of acrylamide, such as polymerization to polyacrylamide, very pure monomer is required, essentially free from anions and metals, which is difficult to obtain through conventional routes. In Hideaki Yamada s group (Kyoto University, Kyoto, Japan), an enzymatic process based on a nitrile hydratase was developed which is currently run on a commercial scale at around 30 000-40 000 tpy with resting cells of third-generation biocatalyst from Rhodococcus rhodochrous J1 (Chapter 7, Figure 7.1). 

Raj, J., Shreenath, P, and Bhalla, T.C. 2006. Rhodococcus rhodochrous PA-34 A potential biocatalyst for acrylamide synthesis. Process Biochemistry, 41 1359-63. 

Rhodococcus sp. N-774 and Pseudomonas chlororaphis B23 resting cells have been used at industrial scale (as first- and second-generation biocatalysts) for the biological production of acrylamide from acrylonitrile since the 1980s [21]. Currently Rhodococcus rhodochrous J1 is being adopted as a third-generation biocatalyst (Mitsubishi Rayon Co.). The industrial production of nicotinamide from 3-cyanopyridine is also operated with this strain (Lonza AG). However, despite the enormous potentiality of nitrile-hydrolyzing biocatalysts for industrial applications, only a few commercial processes have been realized [22]. 

A remarkable example of a lyase-catalyzed commercial process, developed by the Japanese company Nitto and operative since 1985, is the biocatalytic production of acrylamide using immobilized whole cells of Rhodococcus rhodochrous [17]. The enzyme responsible for water addition to the double bond of acrylonitrile is nitrile hydratase ... 

Acrylamide (Ch) Nicotinamide (H) Nitrile hydratase Rhodococcus rhodochrous... 

Current acrylamide production at Mitsubishi using bioconversion is around 40 000 tonnes per year. Using a highly improved cobalt-containing nitrile hydratase from Rhodococcus rhodochrous Jl, final product concentrations of around 700 g L"1... 

Production of acrylamide (Fig. 13) by hydration of acrylonitrile under the action of the intracelluar nitrile hydratase in Rhodococcus rhodochrous (Nitto Chemical Industry Co., Ltd., fed-batch process). The annual production amounts to >30000 tons (see also Table 6). Acrylamide is one of the most important commodity chemicals and is required in large quantities as the pre-polymer of polyacrylamide that is widely used in polymer and floccu-lent applications. The advantages of this hydratase approach in comparison with the classical chemical nitrile hydration are higher product end concentration, quantitative yields, no formation of acrylic acid, no need for copper catalyst, and only five chemical/technical operations instead of seven [73,112,113,171]. An analogous process for nicotinamide is being commercialized by Lonza (see also section 6). 

We found a new microbial enzyme named "nitrile hydratase" which catalyzes the hydration reaction of nitrile to amides. it has been proven that acrylonitrile and methacrylonitrile are easily converted to the corresponding amides. When Rhodococcus rhodochrous J1 resting cells were used as the catalyst, more than 600 g of acrylamide was produced in 1 liter of reaction mixture with a yield of nearly 100 % for acrylonitrile. Since 1991, immobilized R. rhodochrous cells have been used for the industrial production of acrylamide (Fig. 1). At present, more than 10,000 tonnes of acrylamide is produced per year by Nitto Chemical Industries Ltd. 

Acrylamide is the first bulk chemical manufactured using an industrial biotransformation. Acrylamide which is produced 200000 t/a is an important industrial chemical that is mainly processed into water-soluble polymers and copolymers, which find applications as flocculants, paper-making aids, thickening agents, surface coatings, and additives for enhanced oil recovery. The chemical manufacture of acrylamide has been established for a long time, it is based on Cu-catalysis. The production of acrylamide using immobilized whole cells of Rhodococcus rhodochrous is a remarkable example of a lyase-catalyzed commercial process. The enzyme responsible for water addition to the double bond of acrylonitrile is nitrile hydratase (Eq. 4-17) ... 

The production of amides from nitriles has been studied by several workers, and most of them focused on the accumulation of acetamide from acetonitrile [126,133-136]. The enz3nnatic production of acrylamide from acrylonitrile by nitrile hydratase of P. chlororaphis B23, Rhodococcus sp. N-774, and Klebsiella pneumoniae, respectively has been reported [137-142]. These microorganisms exhibited a high nitrile hydratase activity and a low amidase activity, allowing the accumulation of the corresponding amide. Nagasawa et al. optimized the reaction conditions for the production of nicotinamide by a nitrile hydratase, found in Rhodococcus rhodochrous Jl. The enzyme contains cobalt, and shows high activity towards 3-cyanopyridine [143,144]. 

Company in Japan now uses a nitrile hydratase from Rhodococcus rhodochrous to hydrolyse acrylonitrile to acrylamide. The established... 

Acrylamide is one of the most important commodity chemicals for the synthesis of various polymers and is produced in an amount of about 200,000 t/year worldwide. In its conventional synthesis, the hydration of acrylonitrile is performed with copper catalysts. However, the preparative procedure for the catalyst, difficulties in its regeneration, problems associated with separation and purification of the formed acrylamide, undesired polymerization and over-hydrolysis are serious drawbacks. Using whole cells of Brevibacterium sp. [658, 659], Pseudomonas chlororapis [660, 661] or Rhodococcus rhodochrous [662] acrylonitrile can be converted into... 

Synthesis of acrylamide via hydration of acrylonitrile with a wild-type wholecatalyst from Rhodococcus rhodochrous J-1 containing a nitrile hydratase. 

Various nitrile hydratases are continued to be developed and compared to the existing wdld-type whole-cell catalysts (R. rhodochrous Jl) presently used in the commercial production of acrylamide from acrylonitrile. Mitsubishi Rayon has produced mutant enzymes of R. rhodochrous Jl with significantly improved thermal stabilities and ca ytic activities at 50-70°C [233,234]. Saint-Etierme France has licensed and commercialized the mamrfacture of acrylamide using Mitsubishi Rayon s immobilized R. rhodochrous ]l [235] and has independently developed a Rhodococcus pyridinovorans whole cell catalyst for this process [236]. 

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