Table 1. Cloning of amylopullulanase genes from various bacteria.

Organism	Molecular mass (kDa)	Host	Remarks	Reference
Bacillus sp KSM-1378	211	E. coli and Bacillus subtilis	The N-terminal and carboxyl-terminal half of the enzyme constitutes the amylase and pullulanase domains, respectively and are separated by a 35 amino acid sequence tandem repeat. Asp550-Glu579-Asp645 and Asp1464-Glu1493-Asp1581 were reported as catalytic triads for the amylase and pullulanase activity, respectively. Transmission electron microscopy of the purified enzyme revealed a “castanetlike” or “bent dumbbell-like” structure.	Hatada et al. 16
Bacillus sp strain XAL601	220	E.coli	The α-amylase-pullulanase has been overexpressed in E.coli and was found to be alkaline in nature. The enzyme has been found to adsorb strongly to crystalline cellulose (Avicel) and raw corn starch. was analyzed for its binding efficiency to various carbohydrates and was found to have strong adsorbtion to crystalline cellulose (Avicel) and raw corn starch.	Lee et al.13
Bacillus stearothermophilus TS-23	223	E.coli	The expressed gene products obtained were found degenerate with the largest active polypeptide of 220kDa and the smallest one of about 105kDa.	Chen et al.25
Clostridium thermohydrosulfur-icum DSM 3783	165, 130, 100	E.coli	Immunoblotting has revealed more than ten α-amylase-pullulanase specific polypeptides. The largest polypeptide was found to have a molecular weight of about 165kDa, while the smallest enzymatically active polypeptide was about 100kDa. The enzyme was found to be optimally active at 80–85°C, 5°C lower compared with that of the native strain.	Melasniemi and Paloheimo 21
Geobacillus ther-moleovorans NP33	182	E.coli	The 300 amino-acid truncation from the C-terminus enhanced the production, specific enzyme activity, thermostability and starch saccharification efficiency.	Nisha and Satyanarayana66
Lactobacillus plantarum L137	200	L. plantarum NCL21	The N-terminal and C-terminal region of the enzyme was found to possess amino acid sequence repeats. The truncation of the 100 amino acid repeat region of the C-terminus enhanced the production and specific activity of the enzyme.	Kim et al.35; Kim et al.54
Thermoanaerobac-ter ethanolicus 39E	162	E. coli	Asp597, Glu626 and Asp703 have been identified as the catalytic triad by hydrophobic cluster analysis and site-directed mutagenesis studies. The enzyme was found to hydrolyze pullulan at an efficient rate compared with other substrates.	Mathupala et al.;12 Lin and Leu39
Thermoanaerobac-ter saccharolyti-cum B6A-R1	140	E. coli	Highly conserved amino acid residues of the protein have been identified by hydrophobic cluster analysis and multiple sequence alignment.	Ramesh et al.11
Thermoanaerobiu-m brockii	70–100	E. coli and Bacillus subtilis	Secretion of enzyme increased from 0.23U/ml (in T. brockii) to 0.80 to 1.0 U/ml, when B. subtilis was used as an expression host.	Coleman et al.10