**2. Scenario of biocatalysis in pharmaceuticals industries and its pertinent applications**

In 1992, Roger Sheldon estimated environmental impact factor (*E* factor) (kg waste/kg product) for several chemical industries, and an *E* factor of 25–>100 was noted in the pharmaceutical industries [26]. Thus, to reduce the harmful impact of pharmaceutical manufacturing processes and making it more sustainable, "green chemistry" has been increasingly adopted. An efficient biocatalytic process encompasses the "12 principles of green chemistry" to an extent which give it an edge over other technologies [27], as shown in **Figure 1**.

In Europe, a project CHEM21 was launched by the collaboration of both government and industries for the implementation of green technology in the chemical and pharmaceutical sectors [28–30]. The project was launched because of the replacement of biocatalysis over chemical in the synthesis of pharmaceuticals involving several redox reactions, chiral amine synthesis, and regio- and stereospecific hydroxylation of abundant compounds [18, 28, 31]. Since then biocatalysis has been

**25**

**Figure 1.**

*Potential of Biocatalysis in Pharmaceuticals DOI: http://dx.doi.org/10.5772/intechopen.90459*

profitably used for the production of pharmaceutically active chemicals and several blockbuster drugs at the industrial level and some of which are mentioned below:

*Schematic representation of biocatalysis benefits embracing the principles of green chemistry.*

• Sitagliptin—Sitagliptin, an antidiabetic compound, was successfully produced via biocatalytic approach. It finds application in the treatment of type II diabetes and is sold under the trade name "Januvia" by Merck [32, 33]. This work was accomplished by engineering R-selective transaminase (R-ATA, ATA-117) from *Arthrobacter* species by researchers at Codexis and Merck. The drug produced was having 99.95% enantiopurity even in the presence of 1 M i-PrNH2 with 50% DMSO and at a temperature >40°C [33]. Conventionally, it was prepared using rhodium, a heavy metal as a catalyst. However, on comparing both processes, the biocatalytic method showed a massive reduction in waste as well as the use of heavy metal. Besides this, the overall yield and productivity were increased by 10 and 53% [34]. The R- and S-selective ATA was also used in the production of a variety of drugs such as niraparib and the production of an antagonist of orexin receptor with the formation of inhibitor of JAK kinase pathway [35–38].

• Boceprevir—This is a product of chiral amine synthesis and is marketed by Merck under trade name Victrelis. It is used for the treatment of chronic hepatitis C infections. In the production process, monoamine oxidase (MAO) from fungus *Aspergillus niger* was used for the asymmetrical amine oxidation of bicyclic proline intermediate [39]. The biocatalytic process increased yield by 150%, with an overall reduction in raw materials and side products as waste. At present, engineered monoamine oxidase (MAO) is also used in the production of another hepatitis C drug, telaprevir [34, 40], and various other synthetic drugs such as solifenacin, levocetirizine along with few natural alkaloid

• Montelukast—Montelukast or Singulair (trade name) is an anti-asthmatic drug marketed by Merck [41]. The engineered keto-reductase (KRED) was used for the production of montelukast, which displayed significant enantioselectivity

products (confine, harmicine, elegance, and leptaflorine).

*Potential of Biocatalysis in Pharmaceuticals DOI: http://dx.doi.org/10.5772/intechopen.90459*

**Figure 1.**

*Molecular Biotechnology*

**Enzyme class IUPAC** 

**code**

Transferases EC2 Functional group

Hydrolases EC3 Hydrolytic reactions and their

Ligases/synthetases EC6 Formation of a covalent bond

*IUPAC classification of enzymes based on reactions they catalyze.*

reversal

or breakage

or analog

Oxidoreductases EC1 Redox reactions Dehydrogenases, oxidases,

transformation, addition/ elimination involving C-C, C-N, and C-C bond formation

Lyases EC4 Elimination reactions Aldolases, decarboxylases,

joining two molecules together, coupled to hydrolysis of an ATP

Isomerases EC5 Molecular isomerizations Epimerases, racemases

inhibition [13–21].

**Table 1.**

**pertinent applications**

other technologies [27], as shown in **Figure 1**.

However, despite holding tremendous potential, biocatalysis has an inevitable pitfall associated with it when extreme conditions of industrial processes are to be considered. An efficient biocatalyst needs to be compatible enough with specific properties such as thermostability, catalytic ability, substrate specificity, and operational stability in turbulent flow regimes, toxic, hazardous solvents, and substrate

**Catalyzed reactions Important subclasses**

Esterases, glycosidases, lipases, proteases, peptidases, amidases

oxygenases, peroxidases,

dehydratase, few pectinases

intramolecular transferases

C-C, C-N, C-O, C-S ligases

reductases

C1-transferases, glycosyltransferases, aminotransferases, phosphotransferases

Thus, there is a need for the identification and production of stable biocatalysts with broad industrial applicability by exploring and screening novel microbes or identification of new genes with desired properties through the analysis of genes responsible for enzyme production and stability. Further enhancement of the enzyme properties can be done by applying protein engineering tools such as molecular docking, directed evolution, molecular modeling, and process engineering [22–25].

In 1992, Roger Sheldon estimated environmental impact factor (*E* factor) (kg waste/kg product) for several chemical industries, and an *E* factor of 25–>100 was noted in the pharmaceutical industries [26]. Thus, to reduce the harmful impact of pharmaceutical manufacturing processes and making it more sustainable, "green chemistry" has been increasingly adopted. An efficient biocatalytic process encompasses the "12 principles of green chemistry" to an extent which give it an edge over

In Europe, a project CHEM21 was launched by the collaboration of both government and industries for the implementation of green technology in the chemical and pharmaceutical sectors [28–30]. The project was launched because of the replacement of biocatalysis over chemical in the synthesis of pharmaceuticals involving several redox reactions, chiral amine synthesis, and regio- and stereospecific hydroxylation of abundant compounds [18, 28, 31]. Since then biocatalysis has been

**2. Scenario of biocatalysis in pharmaceuticals industries and its** 

**24**

*Schematic representation of biocatalysis benefits embracing the principles of green chemistry.*

profitably used for the production of pharmaceutically active chemicals and several blockbuster drugs at the industrial level and some of which are mentioned below:


(99.9%) and was stable in 70% organic solvent and temperature of 45°C [24]. The biocatalytic method was advantageous in the sense that it omitted the use of hazardous chemical catalyst chlorodiisopinocampheylborane (DIP-CI), which was conventionally used. Several other drugs such as atorvastatin, crizotinib, duloxetine, and phenylephrine were also developed by biocatalytic process using KRED from bacterium *Lactobacillus kefir* [29].



### **Table 2.**

*List of biocatalysts and their microbial source employed for the synthesis of pharmaceutical drugs.*

**27**

**Figure 2.**

*Potential of Biocatalysis in Pharmaceuticals DOI: http://dx.doi.org/10.5772/intechopen.90459*

**3. Conclusion**

**4. Future prospects**

enzymatic deacylation of cephalosporin-C (CPC). A two-step enzymatic process utilizes D-amino acid oxidase (DAAO) and 7-β-(4-carboxybutanamido) cephalosporanic acid acylase (GLA) for two consecutive reactions. Also, a single-step conversion from CPC to 7-ACA has been reported [46]. It has been successfully applied for the conversion of CPC to 7-ACA at industrial level [47]. Similarly, 6-aminopencillanic acid has been reported for the synthesis of

Some other noteworthy examples and recent progress being made in pharmaceutical synthesis using enzymes from various sources are represented in **Table 2**.

Biocatalysis has made a remarkable journey so far and has been successfully applied for the numerous biotransformation processes in several industries. It has benefitted nearly all sectors, particularly chemical and pharmaceuticals. The flourishing development of economically viable and sustainable chemoenzymatic processes highly depends on the broader availability and applicability of enzymes with robust performance irrespective of extreme conditions. Recent surveys have shown that most of the biocatalysts are being used in the synthesis of pharmaceuticals or drugs or intermediates replacing some of the chemical processes, but their

Based on the literature available on the role of biocatalysts in the drug/pharmaceutical synthesis, biocatalysts with improved desired characteristics can be

*Schematic representation of improving the operational stability of biocatalyst and enhancing its performance.*

semisynthetic penicillins using penicillin acylase [48].

stability, selectivity, and specificity are of prime concern.

achieved by a multifaceted approach, as shown in **Figure 2**.

enzymatic deacylation of cephalosporin-C (CPC). A two-step enzymatic process utilizes D-amino acid oxidase (DAAO) and 7-β-(4-carboxybutanamido) cephalosporanic acid acylase (GLA) for two consecutive reactions. Also, a single-step conversion from CPC to 7-ACA has been reported [46]. It has been successfully applied for the conversion of CPC to 7-ACA at industrial level [47]. Similarly, 6-aminopencillanic acid has been reported for the synthesis of semisynthetic penicillins using penicillin acylase [48].

Some other noteworthy examples and recent progress being made in pharmaceutical synthesis using enzymes from various sources are represented in **Table 2**.
