Hydrolysis of Oligosaccharides by a Thermostable α-Galactosidase from Termitomyces eurrhizus

Abstract

The genus of Termitomyces purchased from the market has been identified as Termitomyces eurrhizus using the Internal Transcribed Spacer (ITS) method. An α-galactosidase from T. eurrhizus (TEG), a monomeric protein with a molecular mass of 72 kDa, was purified 146 fold by employing ion exchange chromatography and gel filtration. The optimum pH and temperature was 5.0 and 60 °C, respectively. TEG was stable over pH 2–6, and also exhibited good thermostablility, retaining 100% of the original activity after incubation at 60 °C for 2 h. Inhibition of the enzyme activity by N-bromosuccinimide (NBS) constituted evidence for an essential role of tryptophan in the catalytic action of the isolated enzyme. Besides 4-nitro-phenyl α-d-galactophyranoside (pNPGal), natural substrates could also be effectively hydrolyzed by TEG. Results of thin-layer chromatography (TLC) revealed complete enzymatic hydrolysis of raffinose and stachyose to galactose at 50 °C within 6 h. These properties of TEG advocate its utilization for elevating the nutritional value of soymilk.

Hydrolysis of oligosaccharides by a fungal α‐galactosidase from fruiting bodies of a wild mushroom Leucopaxillus tricolor

“…The optimum pH for the purified LTG was pH 5.0, which was similar to those of Termitomyces eurrhizus , Pseudobalsamia microspore (pH 5.0) , and Pleurotus florida (pH 4.6–5.0) , but higher than those of α‐galactosidases from Coriolus versicolor (pH 3.0) , Pleurotus citrinopileatus (pH 4.4) , Tricholoma matsutake (pH 4.5) , and Lenzites elegans (pH 4.5) (Table ). It is noteworthy that all of the reported mushroom α‐galactosidases were optimally active at an acidic ambient pH, which makes them valuable in several applications occurring at acidic pH .…”

“…It required an ambient temperature of 50 °C for maximal activity, which was in good agreement with reported α‐galactosidases from mushrooms, such as α‐galactosidases from Pleurotus citrinopileatus (50 °C) , Tricholoma matsutake (55 °C) , Pseudobalsamia microspore (55 °C) , Pleurotus florida (55 °C) . On the other hand, Coriolus versicolor , Ganoderma lucidum , Lenzites elegans , and Termitomyces eurrhizus α‐galactosidases demonstrated a higher optimal temperature of 60 °C, 70 °C, 60–80 °C, and 60 °C, respectively. LTG showed poor thermostability at higher temperatures and its activity was completely abolished after treatment at 60 °C for 1 h, which would limit its industrial applications to some extent.…”

“…Nowadays, mushrooms are popular not only in view of their delicious taste but also because of their nutritive value as dietary supplements. In this regard, a few α‐galactosidases were purified from mushrooms, including Pleurotus citrinopileatus , Tricholoma matsutake , Coriolus versicolor , Ganoderma lucidum , Lenzites elegans , Pleurotus florida , Pseudobalsamia microspora , Termitomyces eurrhizus , Agaricus bisporus , and Pleurotus djamor .…”

Biochemical changes associated with electron beam irradiation of rice and links to kernel discoloration during storage

“…Furthermore, α‐galactosidases found in rice have a high affinity for raffinose, hydrolyzing the α‐1,6‐bond (Fujimoto, Kaneko, Momma, Kobayashi, & Mizuno, ). The high temperature could increase their enzymatic activity, as Zhang et al () found fungal α‐galactosidases with the highest relative activity at 60°C.…”

Effect of Domestic Processing and Crude Extract of α-Galactosidase on Oligosaccharide Content of Red Gram (Cajanus cajan L.) Seeds

“…29 Effect of soaking followed by cooking and partly purified α-galactosidase from guar seeds on the oligosaccharide content of Jack bean, Sword beans was investigated and proved that such enzymatic treatment will complement the usage of these beans in human nutrition. 30 Zhang W et al, 31 have reported the complete hydrolysis of raffinose and stachyose to galactose within 6 hours time period at 50 0 C by α-Galactosidase enzyme from Termitomyces eurrhizus. Zhang B et al, 32 have reported the effect of α-Galactosidase treatment on energy metabolism for broilers fed on corn-soybean meal diet.…”