title: Continuous degradation of maltose: improvement in stability and catalytic properties of maltase (α-glucosidase) through immobilization using agar-agar gel as a support.
abstract: Maltose degrading enzyme was immobilized within agar-agar support via entrapment method due to its industrial utilization. The maximum immobilization efficiency (82.77%) was achieved using 4.0% agar-agar keeping the diameter of bead up to 3.0 mm. The matrix entrapment showed maximum catalytic activity at pH 7.0 and temperature 65 °C. Substrate saturation kinetics showed that the K m of immobilized enzyme increased from 1.717 to 2.117 mM ml(-1) where as Vmax decreased from 8,411 to 7,450 U ml(-1 )min(-1) as compared to free enzyme. The immobilization significantly increased the stability of maltase against various temperatures and immobilized maltase retain 100% of its original activity after 2 h at 50 °C, whereas the free maltase only showed 60% residual activity under same condition. The reusability of entrapped maltase showed activity up to 12 cycles and retained 50% of activity even after 5th cycle. Storage stability of agar entrapped maltase retain 73% of its initial activity even after 2 months when stored at 30 °C while free enzyme showed only 37% activity at same storage conditions.
authors.affiliation: The Karachi Institute of Biotechnology and Genetic Engineering (KIBGE), University of Karachi, Karachi, 75270, Pakistan.
authors.forename: Muhammad Asif
authors.initials: MA
authors.lastname: Nawaz
authors.forename: Asad
authors.initials: A
authors.lastname: Karim
authors.forename: Afsheen
authors.initials: A
authors.lastname: Aman
authors.forename: Roberta
authors.initials: R
authors.lastname: Marchetti
authors.forename: Shah Ali Ul
authors.initials: SA
authors.lastname: Qader
authors.forename: Antonio
authors.initials: A
authors.lastname: Molinaro
mesh_terms: D000362:Agar / Q000737:chemistry*; D001407:Bacillus / Q000201:enzymology; D019149:Bioreactors; D002384:Catalysis; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007218:Industrial Microbiology; D007700:Kinetics; D008320:Maltose / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D013696:Temperature; D000520:alpha-Glucosidases / Q000737:chemistry*
chemical_list: D004800:Enzymes, Immobilized; D008320:Maltose; D000362:Agar; D000520:alpha-Glucosidases