Table 1 Novel hydrolytic enzymes and proteins involved in polysaccharide modification and hydrolysis

Cellulases

Bacillus, Pseudomonas, Ruminococcus, Fibrobacter, Clostrdium, Halomonas, Streptomyces, Cellulomonas, Mycobacterium

Endo −1,4 β-D-glucanglucanohydrolase (E. C. 3. 2. 1.4)

Hydrolysis of the internal glycosidic linkages in a random fashion, generating oligosaccharides of varying lengths

Bacillus, Pseudomonas, Clostridium, Paenibacillus, Thermobifida, Cellulomonas, Mycobacterium, Ralstonia

Exoglucanase or 1,4-β-D-glucan cellobiohydrolase (E.C.3.2.1.91)

Hydrolysis of beta-D-glucosidic linkages by releasing mainly cellobiose either from the reducing or non-reducing ends of the chains

Clostridium, Cellulomonas, Aerobacter, Leuconostoc

β - glucosidases or β-D-glucoside gluco-hydrolase (E.C.3.2.1.21)

Hydrolysis of terminal, non-reducing β-D-glucosyl residues with release of β-D-glucose

Clostridium, Cellvibrio

Cellodextrin phosphorylase or (1 → 4)-β-D-glucan:phosphate α-D-glucosyltransferase (E.C. 2.4.1.49)

Catalysis of the reversible phosphorolytic cleavage of cellodextrins ranging from cellotriose to cellohexoses

Cellulomonas, Clostridium, Ruminococcus, Thermotoga, Cellvibrio

Cellobiose phosphorylase or cellobiose: phosphate alpha-D-glucosyltransferase (E.C. 2.4.1.20)

Catalysis of the reversible phosphorolytic cleavage of cellobiose

Hemicellulases

Bacillus, Thermoanaerobacterium, Ruminococcus, Geobacillus, Thermopolyspora, Cellulomonas, Streptomyces

Endo-1,4-beta-D-xylanase or 1,4-beta-xylan xylanohydrolase (EC 3.2.1.8)

Endohydrolysis of (1 → 4)-beta-D-xylosidic linkages in xylans to release xylose

Bacillus, Thermoanaerobacterium, Geobacillus,

Xylan β-1,4-xylosidase (EC 3.2.1.37)

Hydrolysis of (1 → 4)-beta-D-xylans, to remove successive D-xylose residues from the non-reducing termini

Cellulomonas, Bacillus, Clostridium, Rhodothermus

Mannan endo-1,4-beta-mannosidase (EC 3.2.1.78)

Random hydrolysis of (1 → 4)-beta-D-mannosidic linkages in mannans, galactomannans and glucomannans

Bifidobacterium, Thermobacillus, Bacillus, Clostridium, Streptomyces

Alpha-L-arabinofuranosidase (EC 3.2.1.55)

Hydrolysis of terminal non-reducing alpha-L-arabinofuranoside residues in alpha-L-arabinosides

Bacillus, Clostridium, Streptomyces, Fibrobacter, Pseudomonas, Thermoanaerobacterium

Acetyl (xylan) esterase (EC 3.1.1.72)

Hydrolysis of ester linkages of the acetyl groups in position 2 and/or 3 of the xylose moieties of natural acetylated xylan

Thermotoga, Bifidobacterium, Streptococcus, Bacillus, Cellulomonas, Clostridium

Alpha-L-fucoside fucohydrolase or alpha-L-fucosidase (EC 3.2.1.51)

Hydrolysis of O-glycosyl bond in xyloglucan to release l-fucose residues

Thermotoga, Cellvibrio, Bacteroides, Bacillus

Alpha-D-glucosiduronate glucuronohydrolase or α-glucuronidase (EC 3.2.1.139)

Hydrolysis of O-glycosyl bond to release 4-O-methylglucuronic acid from xylan

Novel proteins

Bacillus, Cellulomonas, Clostridium, Myceliophthora, Thermomonospora, Streptomyces, Fibrobacter

Swollenins

Homologous to plant expansins which rapidly induce extension of plant cell walls by weakening the noncovalent interactions; Contain an N-terminal carbohydrate-binding module family 1 domain (CBD) with cellulose-binding function and a C-terminal expansin-like domain.

Loosenins

A novel expansin-type protein with part of the sequence similar to the DPBB (double psi beta barrel) domain present in plant expansins, and fungal β-1,4-endoglucanase family 45; Bind tightly to polysaccharides and show loosening activity which permits sugar release

Streptomyces coelicolor

Cellulose induced proteins (CIP1 and CIP2)

Contain a carbohydrate-binding module (CBM); Hydrolysis of the ester linkage between 4-O-methyl-D-glucuronic acid of glucuronoxylan and lignin alcohols