allowed beyond their permissible limits, cause various ill-effects to the humans and
animals present in the ecosystem is shown in Table 8.
Adsorption is the physical treatment method used to remove these heavy metal
contaminants from various sources. The contaminants are bind by either electrostatic, Van Der Waals or covalent forces. This phenomenal transfer may occur due to
physisorption or chemisorption [83]. Various organic acids interact with the metal
and soil in the distinct ways based on their unique functional groups and types of the
metal complex they formed on interaction. The different concentrations of citric,
malic, acetic, and oxalic acids interact with the metal ions to form a metal complex
that undergoes on the various machines in the removal of different metal pollutants
from soil [84] is shown in Table 9.
9 Conclusion
Agricultural residues are considered as the major substrate in the numerous organic
acid productions because of its excess and easy availability and preferable low-cost
material with eco-friendlier nature to the environment. This tends to be a major shift
from the dependence toward petroleum-based derivatives as the raw materials for
organic acid production. Numerous microbial sources and genetically modified
strains could use these agricultural residues as the major feedstock in the organic
acid production via various methods like hydrolysis, simultaneous saccharification,
and fermentation which are discussed above. These are preferably used by the
Table 7 Genetically modified organisms to produce different organic acids
Genetically modified organism
Feedstock
Organic acid
production
References
Yarrowia lipolytica overexpression of gene
GUT1 and GUT2
Crude glycerol Citric and isocitric
acid
[18]
Raoultella planticola CECT 843
Raw glycerol
2,3-butanediol
[73]
Ustilago trichophora TZ1
Glycerol
Malic acid
[74]
Aspergillus niger LaeA ATCC11414
Glucose
Citric acid
[75]
Aspergillus niger D15
Glucose
Oxalic acid,
Gluconic acid.
[76]
Propionibacterium acidipropionici A strain Glucose
Propionic acid
[77, 78]
Escherichia coli 1650-ME
Glucose and
Glycerol
Succinic acid
[79]
Clostridium glutamicum expression of gltA
gene
Glucose
Itaconic acid
[80]
E. Coli BW25113 expression of ldhA gene Glucose
Pyruvic acid
[81]
80
D. Vishnu et al.
animals present in the ecosystem is shown in Table 8.
Adsorption is the physical treatment method used to remove these heavy metal
contaminants from various sources. The contaminants are bind by either electrostatic, Van Der Waals or covalent forces. This phenomenal transfer may occur due to
physisorption or chemisorption [83]. Various organic acids interact with the metal
and soil in the distinct ways based on their unique functional groups and types of the
metal complex they formed on interaction. The different concentrations of citric,
malic, acetic, and oxalic acids interact with the metal ions to form a metal complex
that undergoes on the various machines in the removal of different metal pollutants
from soil [84] is shown in Table 9.
9 Conclusion
Agricultural residues are considered as the major substrate in the numerous organic
acid productions because of its excess and easy availability and preferable low-cost
material with eco-friendlier nature to the environment. This tends to be a major shift
from the dependence toward petroleum-based derivatives as the raw materials for
organic acid production. Numerous microbial sources and genetically modified
strains could use these agricultural residues as the major feedstock in the organic
acid production via various methods like hydrolysis, simultaneous saccharification,
and fermentation which are discussed above. These are preferably used by the
Table 7 Genetically modified organisms to produce different organic acids
Genetically modified organism
Feedstock
Organic acid
production
References
Yarrowia lipolytica overexpression of gene
GUT1 and GUT2
Crude glycerol Citric and isocitric
acid
[18]
Raoultella planticola CECT 843
Raw glycerol
2,3-butanediol
[73]
Ustilago trichophora TZ1
Glycerol
Malic acid
[74]
Aspergillus niger LaeA ATCC11414
Glucose
Citric acid
[75]
Aspergillus niger D15
Glucose
Oxalic acid,
Gluconic acid.
[76]
Propionibacterium acidipropionici A strain Glucose
Propionic acid
[77, 78]
Escherichia coli 1650-ME
Glucose and
Glycerol
Succinic acid
[79]
Clostridium glutamicum expression of gltA
gene
Glucose
Itaconic acid
[80]
E. Coli BW25113 expression of ldhA gene Glucose
Pyruvic acid
[81]
80
D. Vishnu et al.