title: Development of an ideal starch saccharification process using amylolytic enzymes from thermophiles.
abstract: The extensive efforts to screen thermophilic fungi and bacteria, isolated from various environmental samples, have resulted in the selection of Thermomucor indicae-seudaticae, Geobacillus thermoleovorans NP33 and G. thermoleovorans NP54 for the production of glucoamylase, amylopullulanase and alpha-amylase, respectively. Submerged and solid-state fermentation processes were optimized for maximizing the secretion of glucoamylase by T. indicae-seudaticae. The production of amylopullulanase and alpha-amylase by NP33 and NP54 in submerged fermentation was also optimized. Glucoamylase was optimally active at pH 7.0 and 60 degrees C and was shown to saccharify soluble as well as raw starches. Amylopullulanase and alpha-amylase exhibited optima at pH 7.0 and 100 degrees C and saccharified starch efficiently. Differential inhibition and action on mixed substrates clearly suggested that there are two separate active sites for alpha-amylase and pullulanase activities of amylopullulanase. Both alpha-amylase and amylopullulanase are high maltose-forming and Ca(2+)-independent. These amylolytic enzymes have been shown to be useful in starch saccharification alone and in combination.
authors.affiliation: Department of Microbiology, University of Delhi South Campus, New Delhi-110021, India. tsnarayana@vsnl.net
authors.forename: T
authors.initials: T
authors.lastname: Satyanarayana
authors.forename: S M
authors.initials: SM
authors.lastname: Noorwez
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: J L U M
authors.initials: JL
authors.lastname: Rao
authors.forename: M
authors.initials: M
authors.lastname: Ezhilvannan
authors.forename: P
authors.initials: P
authors.lastname: Kaur
mesh_terms: D000682:Amyloid / Q000737:chemistry*; D001407:Bacillus / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry; D001665:Binding Sites; D001671:Biochemistry / Q000379:methods*; D002118:Calcium / Q000737:chemistry; D005285:Fermentation; D005087:Glucan 1,4-alpha-Glucosidase / Q000737:chemistry; D006026:Glycoside Hydrolases / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D011134:Polysaccharides / Q000737:chemistry*; D011485:Protein Binding; D013213:Starch / Q000737:chemistry*; D013696:Temperature; D013997:Time Factors; D000516:alpha-Amylases / Q000737:chemistry
chemical_list: D000682:Amyloid; D001426:Bacterial Proteins; D011134:Polysaccharides; D013213:Starch; D006026:Glycoside Hydrolases; D000516:alpha-Amylases; D005087:Glucan 1,4-alpha-Glucosidase; C082507:amylopullulanase; D002118:Calcium