Pullulanases are also known as α-dextrin 6-glucanohydrolase. They hydrolyze
endo-acting branched structures that enable maltotriose formation by hydrolyzing
the α-1,6-D-glycosidic linkages in the structure of pullulan, starch, ß-limit dextrin,
amylopectin, and similar oligosaccharides (Asha et al. 2013).
While the thermophilic pullulanases are in GH 13 or GH 57 families, mesophilic
pullulanases are usually in the GH 13 family (Nisha and Satyanarayana 2013).
They are separated into five different categories according to their substrate
specificity and reaction final products.
9.4.3.1 Type I Pullulanase (Pullulan α-1,6-Glucanohydrolase,
α-Dextrin-Endo-1,6-Glucanohydrolase, EC 3.2.1.41)
Type I pullulanases are the enzymes that form maltotriose and linear oligosaccharides by hydrolyzing the 1,6 glycosidic linkages in pullulan, amylopectin, glycogen,
α-limit dextrin, and ß-limit dextrin (Kim et al. 1996; Nisha and Satyanarayana 2016).
9.4.3.2 Type II Pullulanase (Amylopullulanase, EC 3.2.1.1./
41, α-Amylase-Pullulanase, EC 3.2.1.1)
Type II pullulanases are the enzymes that hydrolyze the α-1,4 and α-1,6 linkages that
exist in the structure of starch and pullulan. It releases glucose units by hydrolyzing
the α-1,6 glycosidic linkages in the structure of pullulan.
They can convert the polysaccharides to simple sugars in the absence of enzymes
such as α-amylase or ß-amylase. Since they have both of these dual catalytic
activities, they are also called amylopullulanase or α-amylase-pullulanase (Van der
Maarel et al. 2002; Hii et al. 2012; Nisha and Satyanarayana 2016).
9.4.3.3 Pullulan Hydrolase Type I (Neopullulanase,
Pullulan-4-D-Glucanohydrolase, EC 3.2.1.135)
Pullulan hydrolase type I enables the constitution of the panose (6–0-α-Dglucosylmaltose) units by hydrolyzing the α-1,4 glycosidic links in the structure of
pullulan (Bertoldo and Antranikian 2001). They can hydrolyze the α-1,4 and α-1,6
glycosidic links of starch and similar polysaccharides with low efficiency (Hii et al.
2012).
9 Microbial and Bioinformatics Approach in Biofuel Production
279
endo-acting branched structures that enable maltotriose formation by hydrolyzing
the α-1,6-D-glycosidic linkages in the structure of pullulan, starch, ß-limit dextrin,
amylopectin, and similar oligosaccharides (Asha et al. 2013).
While the thermophilic pullulanases are in GH 13 or GH 57 families, mesophilic
pullulanases are usually in the GH 13 family (Nisha and Satyanarayana 2013).
They are separated into five different categories according to their substrate
specificity and reaction final products.
9.4.3.1 Type I Pullulanase (Pullulan α-1,6-Glucanohydrolase,
α-Dextrin-Endo-1,6-Glucanohydrolase, EC 3.2.1.41)
Type I pullulanases are the enzymes that form maltotriose and linear oligosaccharides by hydrolyzing the 1,6 glycosidic linkages in pullulan, amylopectin, glycogen,
α-limit dextrin, and ß-limit dextrin (Kim et al. 1996; Nisha and Satyanarayana 2016).
9.4.3.2 Type II Pullulanase (Amylopullulanase, EC 3.2.1.1./
41, α-Amylase-Pullulanase, EC 3.2.1.1)
Type II pullulanases are the enzymes that hydrolyze the α-1,4 and α-1,6 linkages that
exist in the structure of starch and pullulan. It releases glucose units by hydrolyzing
the α-1,6 glycosidic linkages in the structure of pullulan.
They can convert the polysaccharides to simple sugars in the absence of enzymes
such as α-amylase or ß-amylase. Since they have both of these dual catalytic
activities, they are also called amylopullulanase or α-amylase-pullulanase (Van der
Maarel et al. 2002; Hii et al. 2012; Nisha and Satyanarayana 2016).
9.4.3.3 Pullulan Hydrolase Type I (Neopullulanase,
Pullulan-4-D-Glucanohydrolase, EC 3.2.1.135)
Pullulan hydrolase type I enables the constitution of the panose (6–0-α-Dglucosylmaltose) units by hydrolyzing the α-1,4 glycosidic links in the structure of
pullulan (Bertoldo and Antranikian 2001). They can hydrolyze the α-1,4 and α-1,6
glycosidic links of starch and similar polysaccharides with low efficiency (Hii et al.
2012).
9 Microbial and Bioinformatics Approach in Biofuel Production
279