A novel thermophile β-galactosidase from Thermothielavioides terrestris producing galactooligosaccharides from acid whey

Anastasia Zerva; Athanasios Limnaios; Anastasia S Kritikou; Nikolaos S Thomaidis; Petros Taoukis; Evangelos Topakas

doi:10.1016/j.nbt.2021.03.002

A novel thermophile β-galactosidase from Thermothielavioides terrestris producing galactooligosaccharides from acid whey

N Biotechnol. 2021 Jul 25:63:45-53. doi: 10.1016/j.nbt.2021.03.002. Epub 2021 Mar 15.

Authors

Anastasia Zerva¹, Athanasios Limnaios², Anastasia S Kritikou³, Nikolaos S Thomaidis³, Petros Taoukis², Evangelos Topakas⁴

Affiliations

¹ Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece.
² Laboratory of Food Chemistry and Technology, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zorgafou Campus, Athens, 157 80, Greece.
³ Laboratory of Analytical Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, 15771, Athens, Greece.
⁴ Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 5 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece. Electronic address: vtopakas@chemeng.ntua.gr.

PMID: 33737224
DOI: 10.1016/j.nbt.2021.03.002

Abstract

β-Galactosidases are key enzymes in the food industry. Apart from the hydrolysis of the saccharide bond of lactose, they also catalyze transgalactosylation reactions, producing galactooligosaccharides (GOS) with prebiotic activity. Here we report the heterologous production in Pichia pastoris of a novel β-galactosidase from the fungus Thermothielavioides terrestris. The enzyme (TtbGal1) was purified and characterized, showing optimal activity at 60 °C and pH 4. TtbGal1 is thermostable, retaining almost full activity for 24 h at 50 °C. It was applied to the production of GOS from defined lactose solutions and acid whey, a liquid waste from the Greek yoghurt industry, reaching yields of 19.4 % and 14.8 %, respectively. HILIC-ESI-QTOF-MS analysis revealed the production of GOS with up to 4 saccharide monomers. The results demonstrate efficient GOS production catalyzed by TtbGal1, valorizing acid whey, a waste with a heavy polluting load from the dairy industry.

Keywords: Acid whey; Galactooligosaccharides; Thermophilic enzymes; Thermothielavioides terrestris; β-galactosidase.

MeSH terms

Hydrogen-Ion Concentration
Oligosaccharides / biosynthesis*
Oligosaccharides / chemistry
Sordariales / enzymology*
Whey / chemistry*
Whey / metabolism
beta-Galactosidase / metabolism*

Substances

Oligosaccharides
beta-Galactosidase

Supplementary concepts

Thermothielavioides terrestris