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Production of amylases from Coprinus comatus under submerged culture using wheat-milling by-products: Optimization, kinetic parameters, partial purification and characterization

Frantz, Suélen Caroline, Paludo, Luana Cristina, Stutz, Herta, Spier, Michele Rigon
Biocatalysis and agricultural biotechnology 2019 v.17 pp. 82-92
Coprinus comatus, alpha-amylase, calcium, culture media, dipotassium hydrogen phosphate, enzyme activity, experimental design, flour, glucan 1,4-alpha-glucosidase, industrial applications, milling byproducts, pH, starch, temperature, urea, wheat
Amylases are enzymes that hydrolyze starch, and are mostly produced from microbial sources. This study aimed to evaluate the potential of utilization of wheat milling by-products for the production of amylases by a macromycete strain, Coprinus comatus, recently discovered as a potential producer of amylases under submerged culture. The best results of enzymatic activity (6.07 U mL−1 for α-amylase and 0.64 U mL−1 for glucoamylases) were obtained in a medium containing 10 g L−1 of low-grade flour (LGF) as substrate. The composition of the culture medium was optimized by experimental designs. The enzymatic activities obtained in the optimized culture medium (105 g L−1 LGF, 3.76 g L−1 urea and 7.52 g L−1 K2HPO4) were 59.40 ± 0.56 U mL−1 and 12.65 ± 0.09 U mL−1 for α-amylases and glucoamylases, respectively, representing an increase of 9.78 and 19.77 fold in the initial enzymatic production. High productivity (0.59 U mL−1 h−1 for α-amylase and 0.11 U mL−1 h−1 for glucoamylase) and product formation yield on substrate consumed (814.28 U gds−1 for α-amylase and 231.24 U gds−1 for glucoamylase) were obtained in the kinetic study. These results show that the use of LGF medium represents a low-cost alternative for the production of amylases by the species studied. The characterization of the partially purified enzymes showed optimal activity at temperature of 50 °C and pH 5.0, in addition to the independence of the calcium ion, a desirable characteristic for amylases produced for industrial application.