et al. 2005; Nishitani et al. 2010). The objective was to raise the potential of these
unique microorganisms in adsorption procedures concerning heavy metal ions than
non-recombinant microorganisms (Bae et al. 2000, 2001; Kuroda et al. 2002;
Kuroda and Ueda 2003; Jiang et al. 2007).
12.5.4.11 The “Cell-Ssurface Display” System
Cell surface proteins are highly significant biomolecules as they are present on the
interface of cell and its environment. The cells consist of various methods to bond
specific proteins on the surface and restrict them to specific areas. A variety of these
methods are being employed in bacteria as well as in S. cerevisiae (Kondo and Ueda
2004). The appearance of heterologous peptides on the surface of the cell (“cellsurface display”) is a great procedure which is very commonly practised in the
biotechnology in different procedures like in manufacturing recombinant vaccines,
antigens, antibodies, enzymes and library peptides (Kuroda et al. 2001; Chen and
Georgiou 2002; Samuelson et al. 2002; Rutherford and Mourez 2006; Wang et al.
2007; Kuroda and Ueda 2010, 2011; Nishitani et al. 2010).
12.6 Factors Affecting Biosorption
The study of the efficiency of metal uptake through microbial biomass is necessary
for the industrial implementation of biosorption to acquire knowledge for the
equilibrium of the procedure needed to plan the machinery for using. Metal uptake
is generally calculated through parameter “q”, which denotes as the milligrams of
metal collected per gram of biosorbent material, while “qH” is described as a
function of the metal stored, the sorbent material utilized and the working environment. The following characteristics influence the biosorption method:
1. Temperature – It does not appear to affect the biosorption performance in the
range of 20–35
C (Aksu 1992);
2. pH – It appears to be the most significant factor in the biosorption process as it
influences the metals solution chemistry and the functional group activity of
biomass and fights amongst metallic ions (Machado et al. 2010);
3. Biomass concentration in solution – It appears to affect specific uptake as with
lower biomass concentrations specific uptake rises (Fourest and Roux 1992;
Gadd and De Rome 1988). According to Gadd and De Rome (1988), higher
biomass concentration interferes with binding sites. Fourest and Roux (1992)
nullified this theory by making low metal concentration in the solution accountable for fall in specific uptake. Therefore, for using microbial biomass like
biosorbent, this fact has to be considered.
4. Biosorption – It is basically utilized to remediate wastewater if there is the
presence of more than one metal ion and the occurrence of the other metal ions
affects the elimination of a specific metal. For instance, uranium is taken up by
bacterium, fungus and yeast biomass and is unaffected by the presence of
manganese, cobalt, copper, cadmium, mercury and lead in the solution
12 Remediation of Heavy Metals Through Genetically Engineered Microorganism
331
unique microorganisms in adsorption procedures concerning heavy metal ions than
non-recombinant microorganisms (Bae et al. 2000, 2001; Kuroda et al. 2002;
Kuroda and Ueda 2003; Jiang et al. 2007).
12.5.4.11 The “Cell-Ssurface Display” System
Cell surface proteins are highly significant biomolecules as they are present on the
interface of cell and its environment. The cells consist of various methods to bond
specific proteins on the surface and restrict them to specific areas. A variety of these
methods are being employed in bacteria as well as in S. cerevisiae (Kondo and Ueda
2004). The appearance of heterologous peptides on the surface of the cell (“cellsurface display”) is a great procedure which is very commonly practised in the
biotechnology in different procedures like in manufacturing recombinant vaccines,
antigens, antibodies, enzymes and library peptides (Kuroda et al. 2001; Chen and
Georgiou 2002; Samuelson et al. 2002; Rutherford and Mourez 2006; Wang et al.
2007; Kuroda and Ueda 2010, 2011; Nishitani et al. 2010).
12.6 Factors Affecting Biosorption
The study of the efficiency of metal uptake through microbial biomass is necessary
for the industrial implementation of biosorption to acquire knowledge for the
equilibrium of the procedure needed to plan the machinery for using. Metal uptake
is generally calculated through parameter “q”, which denotes as the milligrams of
metal collected per gram of biosorbent material, while “qH” is described as a
function of the metal stored, the sorbent material utilized and the working environment. The following characteristics influence the biosorption method:
1. Temperature – It does not appear to affect the biosorption performance in the
range of 20–35
C (Aksu 1992);
2. pH – It appears to be the most significant factor in the biosorption process as it
influences the metals solution chemistry and the functional group activity of
biomass and fights amongst metallic ions (Machado et al. 2010);
3. Biomass concentration in solution – It appears to affect specific uptake as with
lower biomass concentrations specific uptake rises (Fourest and Roux 1992;
Gadd and De Rome 1988). According to Gadd and De Rome (1988), higher
biomass concentration interferes with binding sites. Fourest and Roux (1992)
nullified this theory by making low metal concentration in the solution accountable for fall in specific uptake. Therefore, for using microbial biomass like
biosorbent, this fact has to be considered.
4. Biosorption – It is basically utilized to remediate wastewater if there is the
presence of more than one metal ion and the occurrence of the other metal ions
affects the elimination of a specific metal. For instance, uranium is taken up by
bacterium, fungus and yeast biomass and is unaffected by the presence of
manganese, cobalt, copper, cadmium, mercury and lead in the solution
12 Remediation of Heavy Metals Through Genetically Engineered Microorganism
331