Purification and Characterization of a Thermostable Starch‐Saccharifying Alpha‐1,4‐Glucan‐Glucohydrolase Produced by Bacillus licheniformis

Abstract

To alleviate the difficulties of starch processing industries, it is necessary to improve the enzyme yield of commercially important alpha 1,4-glucan-glucohydrolase (glucoamylase) and explore new thermostable glucoamylases that have strong starch saccharifying capabilities. The current investigation is based on the purification and characterization of glucoamylase from wild and mutant strains of Bacillus licheniformis. Glucoamylase is purified up to homogeneity. The purified glucoamylase exhibits 67-and 506-fold purification from wild (B. licheniformis KIBGE-IB3) and mutant (B. licheniformis KIBGE-IB3M67) strains, respectively, with a molecular weight of ≈185 kDa. Glucoamylase from wild and mutant strains hydrolyzes the starch at 50°C in 5 min. V max and K m values from KIBGE-IB3 are 107.07 kU mg −1 and 0.07 mg mL −1 whereas, for glucoamylase from KIBGE-IB3M67 are 386.56 kU mg −1 and 0.12 mg mL −1 , respectively. End product analysis reveals that glucoamylase from mutant strain have strong saccharifying capability for potato starch. N-Terminal protein sequence discloses that the first two amino acids (SSNKLTTSWG) in the wild-type are replaced by other amino acids in the mutant strain (MDNKLTTSWG). After reviewing potential kinetic properties of glucoamylase, it is suggested that glucoamylase from KIBGE-IB3M67 has remarkable potential to withstand harsh industrial environment and can straightforwardly saccharify potato starch into glucose molecules.

A Utilização De Hibiscus Rosa-Sinensis E Cymbopogon Citratus Para O Tratamento De Hipertensão Arterial Sistêmica: Revisão Integrativa

“…Algumas linhagens de Bacillus são relatadas, por produzirem quantidades superiores de proteínas, além de apresentar alto desempenho de crescimento em fontes de carbono de baixo custo (PAVITHRA et al 2014;GHANI et al 2019;ILYAS et al 2020) e serem adequadas às fermentações em larga escala, o que as tornam excelentes para aplicação industrial (GU et al 2018;RAMESH et al 2020;LI et al 2023). Mazhar et al (2019), otimizaram uma condição de cultivo com resíduos agroindustriais de baixo custo para a produção de lipases termoestáveis por B. amyloliquefaciens sob fermentação em estado sólido.…”