Table 10.

Examples of thermophilic and hyperthermophilic enzymes with potential applications in starch processing

EnzymeOriginPropertiesReference
α-Amylase Desulfurococcus mucosus Optimal activity at 100°C, pH 5.5a 56
Pyrococcus furiosus Optimal activity at 100°C, pH 5.5–6.0; sp act, 3,900 U/mg (98°C); t 1/2, 13 h (98°C) 85
Pyrococcus woesei Optimal activity at 100°C, pH 5.5 188
Pyrodictium abyssi Optimal activity at 100°C, pH 5.0 263
Staphylothermus marinus Optimal activity at 100°C, pH 5.0a 56
Thermococcus profundus Optimal activity at 80°C, pH 4.0–5.0 65, 205
Dictyoglomus thermophilum Optimal activity at 90°C, pH 5.5 109
Thermotoga maritima Optimal activity at 85–90°C, pH 7.0 263
Pullulanase Bacillus flavocaldarius Optimal activity at 75–85°C, pH 6.3;t 1/2, 10 min (107°C) 170, 325
Thermotoga maritima Optimal activity at 90°C, pH 6.0 263
Thermus caldophilus Optimal activity at 75°C, pH 5.5; t 1/2, 72 h (78°C, pH 6.0) 177
Fervidobacterium pennavorans Optimal activity at 80–85°C, pH 6.0;t 1/2, 2 h (80°C) and > 50 h (80°C + starch) 27, 187
Amylopullulanase Desulfurococcus mucosus Optimal activity at 100°C, pH 5.0a 56
ES4Optimal activity on starch at 120°C, pH 5.5–6.5; t 1/2, 6.5 h (98°C) and 20 h (98°C) (+CaCl2) 298
Pyrococcus furiosus Optimal activity at 105°C, pH 6.0; V max(starch), 88 U/mg (98°C),t 1/2, 44 h (90°C) (5 mM CaCl2) 86
Thermococcus celer Optimal activity at 90°C, pH 5.5a 56
Thermococcus litoralis Optimal activity at 117°C, pH 5.5 (5 mM CaCl2) 43
Thermococcus hydrothermalis t 1/2, >8 h (95°C) and 1 h (105°C) 97, 113
Thermoanaerobacter ethanolicus Optimal activity at 90°C, pH 5.5; sp act (starch), 175 U/mg (60°C); t 1/2, 40 min (90°C) 235, 236
Glucoamylase Clostridium thermosaccharolyticum Optimal activity at 70°C, pH 5.0; >90% active after 6 h (70°C) 312
Methanococcus jannaschii Putative gene identified in the genome sequence 21
Thermoanaerobacterium thermosaccharolyticum Optimal activity at 50–60°C, pH 4.0–5.5; stable for 8 h (65°C) 112
α-Glucosidase Thermoanaerobacter ethanolicus Optimal activity at 75°C, pH 5.0–5.5;t 1/2, 46 h (60°C) and 35 min (75°C) 288
β-Amylase Thermotoga maritima Optimal activity at 95°C, pH 4.3–5.5; t 1/2, ca. 30 min (90°C) 300
Thermoanaerobacterium thermosulfurigenes Optimal activity at 75°C, pH 5.5–6.0; stable at pH 3.5–6.5; >80% active after 1 h (75°C) 154, 304
CGTase Thermococcus sp.Optimal activity at 90–100°C, pH 5.0–5.5 (can work at pH 4.5); sp act in CD synthesis, 1,400 U/mg (90°C) (between 69 and 90% α-CD formed); t1/2, 40 min (110°C) 326
Xylose isomerase Thermoanaerobacterium thermosulfurigenes Optimal activity at 80°C, pH 7.5;t 1/2, 35 min (85°C) 204, 244
Thermoanaerobacterium strain JW/SL-YS 489Optimal activity at 80°C, pH 6.8; t 1/2, 1 h (80°C) 221
Thermus aquaticus Optimal activity at 85°C, pH 7.0; t 1/2, 4 days (70°C) 210
Thermotoga maritima Optimal activity at 100–110°C; t 1/2, 10 min (120°C) 44
Thermotoga neapolitana Optimal activity at 97°C, pH 7.1; t 1/2, 2.5 h (80°C)137, 313, 350
  • a Data obtained with crude enzyme (either culture supernatant or cell extract).