Biomedical Engineering Reference
In-Depth Information
Chapter 3
A
PPLICATION OF A
N
ATURAL
B
IOPOLYMER
P
OLY
(
γ
-G
LUTAMIC
A
CID
)
AS A
B
IOFLOCCULANT
AND
A
DSORBENT FOR
C
ATIONIC
D
YES AND
C
HEMICAL
M
UTAGENS
: A
N
O
VERVIEW
B. Stephen Inbaraj
†
and B.H. Chen
*
Department of Food Science, Fu Jen University, Taipei 242, Taiwan
Abstract
Poly(γ-glutamic acid) (γ-PGA), a novel polyanionic and multifunctional macromolecule
synthesized by
Bacillus
species, has attracted considerable attention because of its eco-
friendly, biodegradable and biocompatible characteristics. Recently, its application in a wide
range of fields such as food, agriculture, medicine, hygiene, cosmetics and environment has
been explored. This topic chapter reviews the literature reports on the application of γ-PGA as
a flocculating agent, and adsorbent for cationic dyes and chemical mutagens, affected by
several process parameters including pH, temperature, contact time, metal cations,
concentration and molecular weight of γ-PGA.
1. Introduction
Biopolymers are molecules produced by biological cells including bacteria, fungi, plant
and animal cells. Poly(γ-glutamic acid) (γ-PGA) is a natural and water-soluble biopolymer
produced by a variety of
Bacillus
species through fermentation. The γ-PGA was first
discovered as a major constituent in the capsule of
Bacillus anthracis
, which was
subsequently released into the growth medium upon autoclaving or aging and autolysis of the
cells [1,2]. In a later study, Fujji [3-5] reported fermented soybean (Natto), a traditional health
food in Japan, also contained γ-PGA in the form of viscous sticky mucilage, with
B. subtilis
*
E-mail address: 002622@mail.fju.edu.tw. Tel.: 886-2-29053626, Fax: 886-2-29053415.
†
E-mail address: sinbaraj@yahoo.com
