Ay Sal_2019_Mol.Biol.Rep_46_4385

The ferulic acid esterase (FAE) gene from Geobacillus thermoglucosidasius DSM 2542(T) was cloned into pET28a(+) expression vector and characterized and is being reported in this study for the first time in Geobacillus. The enzyme, designated as GthFAE, was purified by heat shock and ion-exchange column chromatography. In addition, a second clone containing a Histidine tag was expressed and purified by affinity column chromatography demonstrating future potential for scale-up. FAE gene contains an open reading frame (ORF) of 759-bp encoding a hypothetical 252 amino acid protein, a molecular mass of 28.11 kDa and an isoelectric point of 5.53. From this study it was found that GthFAE had optimal activity at 50 degreesC and pH of 8.5. Furthermore, the enzyme has been found to retain 64% of its activity after two days incubation at 50 degreesC and exhibited a high level of functionality with p-nitrophenyl caprylate (C8). K(m), V(max), k(cat) and k(cat)/K(m) values for p-nitrophenyl caprylate were determined as 0.035 mM, 11,735 micromol/min/mg protein, 5491 (1/s) and 156,885 s(-1) mM(-1) respectively. The combination of higher activity and stability compared to previously reported FAEs makes GthFAE a potential candidate for use in the paper manufacturing industry.