Process

The process is carried out in continuous flow fixed bed reactors at 55-60°C temperature. The pH is maintained at 7.5 to 8 by adding Na₂CO₃. MgSO₄ is added as catalysts activator and also help to adjust the pH. Multiple reactors are used to control the product quality. The catalysts have half-life of 50-175 years at 55°C. The schematics in Fig. 1 shows the major steps involved in glucose isomerise process. Filter removes the materials that can plug the catalysts pores. Carbon adsorbent bed is used to remove the impurities that can poison the catalysts. The feed evaporator concentrate the feed to 35-45 % .

Fig.1. Schematics showing major steps in glucose isomerise process

2. Chiral synthesis of L-aspartic acid

L-aspartic acid is widely used in food and pharmaceutical industries for example in production of low calorific sweetener aspartame and in treatment of leukemia respectively. It is produced by the reaction of fumaric acid with ammonia over L-aspartase

Isolated enzymes are highly unstable. It is prepared by trapping E.colli cell in matrix of polyacryl amide or poly urethane. The immobilized cells are very active at 35-40°C achieving 95% conversion. The half-life of these immobilized cells is 120-680 days. Reaction is conducted at column reactor at 37°C at pH 8.5 using a feed of ammonium fumarate. MgCl₂ is added for catalyst stability.

3.  Enzymatic hydrolysis : production of 6 aminopenicillanic acid (6-APA)

The 6 aminopenicillanic acid is produced by penicillin-acylase catalyzed acetal hydrolysis of penicillins G and U. It is used to produce a large family of highly effective antibiotics such as ampicillin and amoxicillin. Acylase catalyzed hydrolysis of penicillin G involves the removal of the phenyacetyl side chain to produce phenylacetic acid and 6-APA as shown below .

Reaction occurs at 35°C at pH 7-8. The pencillin acylase can be obtained from bacterial and fungal organisms. Bacterial acylase are best for penicillin G and fungal acylase most active for penicillin U.

Production of 6-APA is conducted in a stirred batch reactor or continuous stirred tank reactor (CSTR) at 35-40 0 C and 7-8 pH using a feed of 4-15 wt% penicillin G. The pH of the reactor is controlled at 7-8 by continuous addition of alkali to compensate for production of phenylacetic acid.

Text reference

• Piet W.N.M. van Leeuwen, Homogeneous catalysis: Understanding the Art, Springer, 2004
• Piet W.N.M. van Leeuwen, and John C. Chadwick, Homogeneous catalysis: Activity-stability –deactivation, Wiley, VCH, 2011
• H. Bartholomew and R. J. Farrauto, Fundamentals of Industrial catalytic Processes , Wiley, VCH, 2006