Galacto-oligosaccharides Synthesis from Lactose and Whey by β-Galactosidase Immobilized in PVA

Abstract

The synthesis of galacto-oligosaccharides (GOS) by β-galactosidase immobilized in both polyvinyl alcohol (PVA) lenses and sol-gel carriers was studied and compared with the performance of the free enzyme. PVA-immobilized β-galactosidase retained 95 % of the initial activity after seven repeated uses and retained 51 % of the initial activity after 3 months of storage, while sol-gel-immobilized β-galactosidase only retained 39 % of the initial activity under storage. Lactose conversion takes place at a higher rate in the PVA-immobilized β-galactosidase, while the lowest rate of lactose conversion was noticed with immobilized β-galactosidase in sol-gel. Continuous production of GOS from either lactose or whey, with PVA-immobilized β-galactosidase, was performed in a packed-bed reactor. A maximum GOS production of 30 % of total sugars was attained for a 40-% lactose feed solution with a feed rate of 10.8 ml/h, at pH 4.5 and 40 °C, corresponding to a productivity of 117 g/l h. The maximum GOS productivity of 344 g/l h was obtained at a flow rate of 28.7 ml/h. 3-OS and 4-OS were the major types of GOS formed. Conversion of whey in continuous mode resulted in GOS production of 15 % of total sugars and formation of 45 % 3-OS, 40 % 4-OS, and 15 % 5-OS.

Whey valorization using transgalactosylation activity of immobilized β‐galactosidase

“…Namely, the obtained maximum GOS concentration in case of the immobilized preparation was achieved for 4 h, while the same GOS concentration with the soluble enzyme was achieved in 10 h. Therefore, it can be concluded that enzyme specificity shifted towards the reaction of transgalactosylation, bearing in mind that same hydrolytic activities of both preparations were employed in the reaction, and that 2.5-fold enhancement of reaction productivity was achieved. Results of this study are important since there are a few examples of applied immobilized preparations for concentrated whey transformation (Jovanovic-Malinovska et al, 2012), although this reaction is already well established, as it can be seen in several review papers (Nath et al, 2016;Fischer & Kleinschmidt, 2018).…”

“…However, with arousing awareness on lactose abundance in dairy effluents, cheaper and more versatile substrates, such as whey (Fischer & Kleinschmidt, 2015;Geiger et al, 2016;Sen et al, 2016) and whey permeate (Eskandarloo & Abbaspourrad, 2018;Mano et al, 2018), or even milk (Cao et al, 2017;Zhu et al, 2018), have been taken into account. Also, despite the fact that the various methods for the immobilization of b-galactosidases were proposed so far (Giacomini et al, 1998;Albayrak & Yang, 2002;Torres et al, 2003;Gaur et al, 2006;Grosov a et al, 2008;Neri et al, 2009;Guidini et al, 2010;Klein et al, 2012;Urrutia et al, 2013;Carevi c et al, 2016b;de Albuquerque et al, 2018;Levin et al, 2018;Guerrero et al, 2019;Kessi & Arias, 2019), the examples of immobilized enzyme preparations utilized in these reactions are rather scarce (Jovanovic-Malinovska et al, 2012;de Albuquerque et al, 2018;Eskandarloo & Abbaspourrad, 2018).…”

Microbial Glycosidases for Nondigestible Oligosaccharides Production

“…When whey permeate was used as substrate in a membrane reactor system, a mixture of GOs with 77-78% of purity was produced [15]. A high lactose conversion was achieved (70-80%), when using whey as a substrate in the production of GOs, yielding 10-20% of total sugars and producing oligomers with DP3, DP4, and DP5 [16]. The GOs production from whey permeate yielded 50% corresponding to 322 g prebiotics/kg whey permeate, presenting tagatose and lactulose in the oligosaccharides mixture [17].…”

The impact of membrane pretreatment on the enzymatic production of whey‐derived galacto‐oligosaccharides

“…Previous studies on GOS production from whey have been conducted on (protein‐containing) rehydrated powder of whey (Fischer & Kleinschmidt, ; Jovanovic‐Malinovska, Fernandes, Winkelhausen, & Fonseca, ; Klein et al, ; Lisboa et al, ; T. S. Song et al, ) and on (protein‐free) rehydrated powder of whey UF‐permeate (Foda & Lopez‐Leiva, ; López Leiva & Guzman, ; Rustom, Foda, & López‐Leiva, ; Pocedičová, Čurda, Mišún, Dryáková, & Diblíková, ) using various processing technologies including stirred tank reactors (STR), packed bed reactors, and inert and catalytic membrane reactors. These studies have used either fungal [derived from Aspergillus sp .…”

“…These studies have used either fungal [derived from Aspergillus sp . (Fischer & Kleinschmidt, ; Jovanovic‐Malinovska et al, ; López Leiva & Guzman, ; Rustom et al, ) and Kluyveromyces lactis (Fischer & Kleinschmidt, ; Foda & Lopez‐Leiva, ; Klein et al, ; Lisboa et al, ; Pocedičová et al, ; Rustom et al, )] or bacteria‐originated (derived from Lactobacillus paracasei [T. S. Song et al, ]) enzymes. It has been shown by several authors (Fischer & Kleinschmidt, ; Pocedičová et al, ; Splechtna et al, ) that the type of substrate matrix (i.e., whether it is a buffered lactose, buffered lactose with addition of salts, whey, UF‐permeate, etc.)…”