A BRIEF OUTLOOK ON PGA IMMOBILISATION WITH FEW LITERATURE CITATIONS

1. Immobilisation of Penicillin G Acylase
Dr Sumitha
J
Associate Professo
r
JBAS College for Women,Chennai-18

2. Penicillin G Acylase(PGA)
This enzyme hydrolyzes penicillin G into phenyl acetic acid and 6-amino
penicillanic acid (6-APA). Both natural and semi-synthetic penicillins contain
6-aminopenicillanic acid
.
This enzyme is the starting material for the manufacture of penicillin
derivatives, which are the most widely used β-lactam antibiotics
.
Based on their substrate speci
fi
city, penicillin acylases have been classi
fi
ed into
three groups viz., penicillin G-acylases, penicillin-V-acylases and ampicillin
acylases

3. Penicillin G Acylase(PGA)
Penicillin acylases are involved in the industrial production of semi synthetic
penicillins and cephalosporins, which remains the most widely used group of
antibiotics
.
Semi synthetic pencillins exhibit better properties such as increased stability,
easier absorption and fewer side e
ff
ects. Penicillin G and V and represent a
practical solution to the problem of adaptive microbial resistance to antibiotics
.
Both penicillin G acylase and penicillin V acylase used for industrial production
of 6-APA

4. PVA Vs PGA
Penicillin V acylase has some advantages over penicillin G acylase
better stability
higher conversion rates
.
Penicillin V acylase Limitation
s
non-availability of suitable bacterial strains
cost issues

5. Immobilisation of PGA
PGA enzyme preparation has to be active, robust and reusable.
The most e
ff
ective way to enhance stability for many enzymes is to immobilize
them onto solid support which also o
ff
ers re-use and cost-e
ff
ectiveness

6. Immobilisation of PGA
The enzyme preparation with the highest speci
fi
c activity (322 U/g dry matrix
at 40°C and pH 8.0) was obtained by covalent binding of penicillin acylase to
vinyl copolymers (Dhal et al., 1985)
Singh et al. (1988) used double entrapment methodology for the immobilization
of penicillin acylase from E. coli NCIM 2563 on agar-polyacrylamide resins
.
Danzig et al. (1993) used penicillin acylase produced by genetically engineered
E. coli and immobilized it on polyacrylamide carrier for improved 6-APA
production.

7. Immobilisation of PGA
Chemical modi
fi
cation of immobilized penicillin acylase from E. coli has been
reported with formaldehyde followed by sodium borohydride reduction. The
derivative modi
fi
ed with formaldehyde and further reduced with borohydride
was much more stable than the original unmodi
fi
ed preparation (Blanco and
Guisan, 1989
)
The use of copolymers of acrylonitrile, vinyl acetate, butylacrylate (Bryjak et
al., 1993), and ethyl acrylate (Bryjak et al., 1989) with cross-linking agents such
as divinylbenzene or ethylenedimethacrylate (Bryjak and Noworyta, 1993) has
been reported
.

8. Immobilisation of PGA
The penicillin acylase immobilized on copolymers of butyl acrylates and
ethyleneglycol dimethacrylate had a signi
fi
cantly enhanced reaction rate
compared to penicillin hydrolysis by the native enzyme. (Bryjak and Noworyta,
1993).
Fonseca et al. (1993) used grace silica gel carrier activated by a silanization
method for immobilization of penicillin acylase.
Banerjee and Debnath (2007) described the continuous production of 6-APA in
a packed column reactor by using agarose immobilized penicillin acylase as a
block polymer. The strain Escherichia coli ATCC 11105 was used as enzyme
source and penicillin G as substrate.

9. Application
Of PA Synthesis of 6-APA
production of pure
chiral compounds
Synthesis of
dipeptides
Decolourization of
dyes
Biosensor
s