title: Thermostable α-amylase immobilization: Enhanced stability and performance for starch biocatalysis.
abstract: The uses of thermostable starch hydrolytic biocatalysts are steadily increasing for the industrial application because of their obvious need for biocatalytic performance at elevated temperatures. The starch liquefaction and saccharification can be carried out simultaneously by the use of thermostable starch hydrolytic biocatalysts, thus minimizing the unit operations, time, and efforts. The cost factor hampers the industrialization of expensive soluble (free) enzymes for biocatalytic applications and the immobilization of enzymes offers promising alternative to the hurdle. The present investigation was aimed for immobilization of thermostable α-amylase using calcium alginate, and statistical optimization studies were carried out for enhanced biocatalytic performance. Initially, one-parameter at a time optimization studies were carried out for identification of significant factors influencing the immobilization. Furthermore, a statistical approach, response surface methodology, was applied for immobilization of α-amylase. The immobilized α-amylase in alginate microbeads showed enhanced stability to temperature and reusable property for up to seven cycles (with the retention of 50% initial activity). Finally, the kinetic behavior of free and immobilized enzyme showed the Km value of 1.2% and 2.6% (w/v) and Vmax of 1,020 and 1,030 U, respectively. Fifty percent reduction in affinity of the immobilized enzyme toward substrate was compensated by its longer stability.
authors.affiliation: Department of Microbiology, Sri Venkateswara University, Tirupati, India.
authors.forename: Gudi Satheesh
authors.initials: GS
authors.lastname: Kumar
authors.affiliation: Department of Chemistry, Indian Institute of Technology Delhi, New Delhi, India.
authors.forename: Gulam Mohmad
authors.initials: GM
authors.lastname: Rather
authors.affiliation: Department of Chemical, Biochemical and Environmental, Engineering, Technology Research Centre, Centre for Advanced Sensor Technology, University of Maryland Baltimore County (UMBC), Baltimore, MD, USA.
authors.forename: Chandrasekhar
authors.initials: C
authors.lastname: Gurramkonda
authors.affiliation: Department of Microbiology, Sri Krishnadevaraya University, Anantapur, India.
authors.forename: Bontha Rajasekhar
authors.initials: BR
authors.lastname: Reddy
mesh_terms: D000464:Alginates / Q000737:chemistry; D001407:Bacillus / Q000737:chemistry / Q000201:enzymology* / Q000378:metabolism; D055162:Biocatalysis; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry / Q000378:metabolism*; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007218:Industrial Microbiology; D007700:Kinetics; D008863:Microspheres; D013213:Starch / Q000378:metabolism*; D013696:Temperature; D000516:alpha-Amylases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000464:Alginates; D004800:Enzymes, Immobilized; D006603:Hexuronic Acids; D020723:Glucuronic Acid; D013213:Starch; D000516:alpha-Amylases
keywords: Alicyclobacillus acidocaldorius; alginates; immobilization; optimization; thermostable α-amylase