Synthesis of Galactosyl Derivative of Gluconic Acid with Transglycosylation Activity of β-galactosidase

Abstract

SummaryBionic acids are bioactive compounds demonstrating numerous interesting properties. They are widely produced by chemical or enzymatic oxidation of disaccharides. This paper focuses on the galactosyl derivative of gluconic acid as a result of a new method of bionic acid synthesis which utilises the transglycosylation properties of β-galactosidase and introduces lactose as a substrate. Products obtained in such a process are characterised by different structures (and, potentially, properties) than those resulting from traditional oxidation of disaccharides. The aim of this study is to determine the effect of selected parameters (concentration and ratio of substrates, dose of the enzyme, time, pH, presence of salts) on the course of the reaction carried out with the enzymatic preparation Lactozym, containing β-galactosidase from Kluyveromyces lactis. Research has shown that increased dry matter content in the baseline solution (up to 50 %, by mass per volume) and an addition of NaCl contribute to higher yield. On the other hand, reduced content of the derivative is a result of increased pH from 7.0 to 9.0 and an addition of magnesium and manganese salts. Moreover, exceeding the β-galactosidase dose over approx. 35 000 U per 100 g of lactose also leads to reduced yield of the process. The most favourable molar ratio of sodium gluconate to lactose is 2.225:0.675. Depending on the conditions of the synthesis, the product concentration ranged between 17.3 and 118.3 g/L of the reaction mixture, which corresponded to the mass fraction of 6.64-23.7 % of dry matter. The data obtained as a result of the present study may be useful for designing an industrial process.

Active Site Architecture and Reaction Mechanism Determination of Cold Adapted β-d-galactosidase from Arthrobacter sp. 32cB

“…Similar to Ecol βDG, it consists of 1032 aa and its functional form is a homotetramer. Not only it catalyzes lactose hydrolysis, but also transglycosylation reaction that results in formation of galactose derivatives, among other alkyl-galactosides [11], gal-mannitol, [12], and bionic acids [13].…”

Application of Transgalactosylation Activity of β-Galactosidase from Kluyveromyces lactis for the Synthesis of Ascorbic Acid Galactoside

“…Other molecules possessing a hydroxyl group can be used as acceptor (e.g. sugars such as fructose [ 33 ], polyols such as glycerol [ 34 ], mannitol [ 35 ] and polyhydroxy acids such as gluconic acid [ 36 ]). In this case, the galactosyl moiety from lactose was transferred onto an ascorbic acid molecule as a result of activity of β-galactosidase produced by K. lactis .…”

“…5 ). The initial tested variant (sodium ascorbate and lactose introduced at a molar ratio of 1:0.526) was selected on the basis of previous research concerning galactosyl derivative of gluconic acid [ 36 ]. Comparing the concentration of ascorbic acid galactoside (as % of dry mass) in the post-reaction mixture, that ratio proved to be the best.…”

“…while 0.1 M MnCl 2 solution caused a decrease of about one quarter (1.93% d.m.). In the case of galactosyl derivative of gluconic acid, an increase by 17.5% was achieved after introducing NaCl compared with the reaction mixture without any salts [ 36 ]. The application of MgCl 2 solution resulted in the fall of the final derivative content (even by 12.9% for 1 M MgCl 2 ).…”

Mapping the Transglycosylation Relevant Sites of Cold-Adapted β-d-Galactosidase from Arthrobacter sp. 32cB

“…Nowadays, both for lactose removal and GOS/HOS synthesis, the β- d -galactosidase from Kluyveromyces lactis is predominantly used [ 33 , 34 , 35 , 36 ]. Introduction of new enzyme into food production must be preceded by a number of studies that will not only ensure its high efficiency but will also ensure the consumers’ safety.…”