Bioprocessing Approaches to Synthesize Bio-based Surfactants and Detergents - Food and Industrial Bioproducts and Bioprocessing - page 249

NH 2

1. Papain (Acetonitrile/borate
buffer, 25°C, 24h)

O

+ H 3 N

(- ____ OH)

O

Cl -

N
H

H
N O

O

L-Arginine-O- a -Octyl
Amide Dihydrochloride

2. Chromatographic purification
3. Hydrogenation (Pd)

O

N a -benzyloxy-L-Arginine
Methyl Ester Hydrochloride

NH

O

(- )

+ H 2 N

NH

O

NH 2 +

Cl -

+ H 2 N

O

NH 2 +

Cl -

Cl - +

H 3 N

O

OH

1. Papain (Solvent-free, 50°C, 48 h)
(- ____ OH)
2. Chromatographic purification
3. Hydrogenation (Pd)

L-Arginine-O- -Octyl

Ester Dihydrochloride

a

NH

O

+

(- )

H 2 N

NH 2 +

Cl -

O

Figure 10.5 Synthesis of long-chain amide and ester of the -carboxylic acid moiety of arginine using

papain as biocatalyst and fatty amine and alcohol as reactant, respectively (adapted from Infante et al .,
2009a).

α

and the unprotected -OH group of N-Cbz-protected serine as acyl acceptors, using lipases

as catalysts in the presence of apolar solvent, using a molar excess of acyl donor free fatty
acid or TAG (Soo et al ., 2003 ; Valivety et al ., 1997 ; Nagao and Kito, 1989 ; Gardossi et al .,
1991 ; Montet et al ., 1990 ).
An additional example is the synthesis of acylated glycerol-argnine conjugates using
lipases (Figure 10.6 ) (Infante et al ., 2009 a). In the first, the

ε

-carboxylic acid group of N α -
acetylated L-arginine was conjugated with glycerol using immobilized papain or C.
antarctica lipase as biocatalyst at 50 °C in the presence of 0.2 M borate buffer, pH = 8.2,
yielding an ester at 80% conversion. The majority of the product contained an ester bond at
the 1- and 3- glycerol position; but, a small, 10% yield of ester at the 2-glycerol position
occurred. The second step involved immobilized R. miehei lipase-catalyzed esterification of
the glycerol moiety's free -OH groups under solvent-free conditions at 65 °C, with the acyl
donor, typically lauric acid, also serving as solvent. Di-acylated products occurred at a high
yields, 50-75%, with the product distribution containing a mixture of positional isomers
(Figure 10.6), resulting from the occurrence of acyl migration.

α

10.5.6 Enzymatic production of lysophospholipids and
structured phospholipids
The enzymatic cleavage of an acyl group from phospholipids yields lysophospholipids,
which are more water soluble than phospholipids and, therefore, useful as emulsifiers for
oils in water. Three enzymes have been employed to conduct hydrolysis, including
phospholipases A 1 and A 2 , which cleave the fatty acyl group from the 1- and 2-glycerol