Characterization of thermostable beta-1,4-galactanase and its application in hydrolysis of pectin from sweet potato (Ipomoea batatas (l.) lam) peels

• Main Authors: Ismail, Noor Faizah, Abang Zaidel, Dayang Norulfairuz, Mat Isa, Mohd. Noor
• Format: Article
• Language: English
• Published: Penerbit UTM Press 2021
• Subjects: TP Chemical technology
• Online Access: http://eprints.utm.my/id/eprint/97273/1/DayangNorulfairuz2021_CharacterizationOfThermostableBeta14GalactanaseAndItsApplication.pdf; http://eprints.utm.my/id/eprint/97273/; http://dx.doi.org/10.11113/jurnalteknologi.v83.17198

Galactooligosaccharides (GOS) synthesis has received much attention due to its prebiotic function. Beta-1,4-galactanase responsible for the hydrolysis of galactan plays an important role in producing GOS from biodegradation of this pectin component. In this study, beta-1,4-galactanase (BgcGC) from a thermophilic Geobacillus mahadii Geo-05 was heterologously expressed in Escherichia coli (E. coli) and characterized. The optimum temperature of BgcGC was at 60°C and stable from 20-60°C while optimum pH was at 6 and stable from pH 4-10. BgcGC showed high catalytic efficiency towards potato galactan (873.8 ml mg-1 s-1) and lupin galactan (1694.4 ml mg-1 s-1). The activity of BgcGC was not significantly affected with the presence of 100 mM K+, Tween-20 and 2-mercaptoethanol. Application of BgcGC towards pectin-containing galactan oligomer extracted from sweet potato peels resulted in galactose and GOS synthesis as revealed by high performance liquid chromatography analysis. Thus, this enzyme has a potential to be one of the enzyme candidates involves in pectin complex degradation to produce GOS.