# The Stability Improvement of alpha-Amylase Enzyme from Aspergillus fumigatus by Immobilization on a Bentonite Matrix

Biochem Res Int. 2022 Jan 10;2022:3797629. doi: 10.1155/2022/3797629. eCollection 2022.

**ABSTRACT**

The stability of the *α*-amylase enzyme has been improved from *Aspergillus fumigatus* using the immobilization method on a bentonite matrix. Therefore, this study aims to obtain the higher stability of *α*-amylase enzyme from *A. fumigatus*; hence, it is used repeatedly to reduce industrial costs. The procedures involved enzyme production, isolation, partial purification, immobilization, and characterization. Furthermore, the soluble enzyme was immobilized using 0.1 M phosphate buffer of pH 7.5 on a bentonite matrix, after which it was characterized with the following parameters such as optimum temperature, Michaelis constant (*K* _{M} ), maximum velocity (*V* _{max}), thermal inactivation rate constant (*k* _{i}), half-life (*t* _{1/2}), and the change of energy due to denaturation (Δ*G* _{i} ). The results showed that the soluble enzyme has an optimum temperature of 55°C, *K* _{M} of 3.04 mg mL^{-1} substrate, *V* _{max} of 10.90 *μ*mole mL^{-1} min^{-1}, *k* _{i} of 0.0171 min^{-1}, t_{1/2} of 40.53 min, and Δ*G* _{i} of 104.47 kJ mole^{-1}, while the immobilized enzyme has an optimum temperature of 70°C, *K* _{M} of 8.31 mg mL^{-1} substrate, *V* _{max} of 1.44 *μ*mole mL^{-1} min^{-1}, *k* _{i} of 0.0060 min^{-1}, *t* _{1/2} of 115.50 min, and Δ*G* _{i} of 107.37 kJ mole^{-1}. Considering the results, the immobilized enzyme retained 42% of its residual activity after six reuse cycles. Additionally, the stability improvement of the *α*-amylase enzyme by immobilization on a bentonite matrix, based on the increase in half-life, was three times greater than the soluble enzyme.

PMID:35047221 | PMC:PMC8763562 | DOI:10.1155/2022/3797629

Source: Industry