118
acids in human and other animals (Spector and Kim 2015; Smith and Mukhopadhyay
2012). In this quest of lipids with nutritional value, polyunsaturated fatty acids
(PUFAs) deserve a special mention.
PUFAs are a class of fatty acids characterized by the presence of long carbon
chains with two or more double bonds. They are further broadly classified as ω-3,
ω-6 and ω-9 on the basis of location of double bond with respect to terminal methyl
group (Srianta et al. 2010; Kothri et al. 2020). The biosynthesis of PUFA occurs by
an extension of saturated fatty acid pathway to produce linoleic acid, a precursor of
ω-6 and ω-3 series of PUFA (Gill and Valivety 1997). A series of sequential desaturation and elongation steps occurs which introduces double bond at specific locations and adds two carbon atoms to the existing fatty acyl chain (Kim et al. 2014) as
shown in Fig. 7.1. PUFAs are formed by a special class of desaturases called unsaturated fatty acid desaturases, and their type, activity and expression level are what
determines the type of PUFA profile a cell is capable of generating (Czumaj and
Śledziński 2020). The first microbial oil rich in γ-linolenic acid (GLA) was commercially produced by J&E Sturge (UK) using filamentous fungi Mucor
Stearic acid (C 18:0 )
Oleic acid (C 18:1 )
Delta-9 desaturase
Delta-15 desaturase
Delta-6 desaturase
Elongase
Delta-5 desaturase
Elongase, Delta 4 desaturase
W-6 series
1-prostagladins
4-leukotrienes
5-leukotrienes
2-prostagladins
3-prostagladins
2-thromoxanes
2-thromoxanes
W-3 series
Delta-12 desaturase
Linoleic acid (C 18:2 )
γ-Linoleic acid (C 18:3 )
α Linoleic acid (C 18:3 )
Stearidonic acid (C 18:4 )
Eicosatetraeonic acid (C 20:4 )
Eicosapentaeonic acid (C 20:5 )
Docosahexaeonic acid (C 22:6 )
Dihomo γ-Linoleic acid (C 20:3 )
Arachidonic acid (C 20:4 )
Docosapenteaonic acid (C 22:5 )
Fig. 7.1 Bioconversion of polyunsaturated fatty acids via aerobic desaturase/elongase enzymes
with their potential bioactive role in mammals. (Adapted from Gill and Valivety 1997; Ochsenreither
et al. 2016)
R. Gupta and S. Gaur
acids in human and other animals (Spector and Kim 2015; Smith and Mukhopadhyay
2012). In this quest of lipids with nutritional value, polyunsaturated fatty acids
(PUFAs) deserve a special mention.
PUFAs are a class of fatty acids characterized by the presence of long carbon
chains with two or more double bonds. They are further broadly classified as ω-3,
ω-6 and ω-9 on the basis of location of double bond with respect to terminal methyl
group (Srianta et al. 2010; Kothri et al. 2020). The biosynthesis of PUFA occurs by
an extension of saturated fatty acid pathway to produce linoleic acid, a precursor of
ω-6 and ω-3 series of PUFA (Gill and Valivety 1997). A series of sequential desaturation and elongation steps occurs which introduces double bond at specific locations and adds two carbon atoms to the existing fatty acyl chain (Kim et al. 2014) as
shown in Fig. 7.1. PUFAs are formed by a special class of desaturases called unsaturated fatty acid desaturases, and their type, activity and expression level are what
determines the type of PUFA profile a cell is capable of generating (Czumaj and
Śledziński 2020). The first microbial oil rich in γ-linolenic acid (GLA) was commercially produced by J&E Sturge (UK) using filamentous fungi Mucor
Stearic acid (C 18:0 )
Oleic acid (C 18:1 )
Delta-9 desaturase
Delta-15 desaturase
Delta-6 desaturase
Elongase
Delta-5 desaturase
Elongase, Delta 4 desaturase
W-6 series
1-prostagladins
4-leukotrienes
5-leukotrienes
2-prostagladins
3-prostagladins
2-thromoxanes
2-thromoxanes
W-3 series
Delta-12 desaturase
Linoleic acid (C 18:2 )
γ-Linoleic acid (C 18:3 )
α Linoleic acid (C 18:3 )
Stearidonic acid (C 18:4 )
Eicosatetraeonic acid (C 20:4 )
Eicosapentaeonic acid (C 20:5 )
Docosahexaeonic acid (C 22:6 )
Dihomo γ-Linoleic acid (C 20:3 )
Arachidonic acid (C 20:4 )
Docosapenteaonic acid (C 22:5 )
Fig. 7.1 Bioconversion of polyunsaturated fatty acids via aerobic desaturase/elongase enzymes
with their potential bioactive role in mammals. (Adapted from Gill and Valivety 1997; Ochsenreither
et al. 2016)
R. Gupta and S. Gaur