Cloning, Expression and Characterization of a Novel Cold-adapted β-galactosidase from the Deep-sea Bacterium Alteromonas sp. ML52

As prebiotics, galacto-oligosaccharides (GOSs) can improve the intestinal flora and have important applications in medicine. β-galactosidases could promote the synthesis of GOSs in lactose and catalyze the hydrolysis of lactose. In this study, a new β-galactosidase gene (gal2A), which belongs to the glycoside hydrolase family 2, was cloned from marine bacterium Alteromonas sp. QD01 and expressed in Escherichia coli. The molecular weight of Gal2A was 117.07 kDa. The optimal pH and temperature of Gal2A were 8.0 and 40 °C, respectively. At the same time, Gal2A showed wide pH stability in the pH range of 6.0–9.5, which is suitable for lactose hydrolysis in milk. Most metal ions promoted the activity of Gal2A, especially Mn2+ and Mg2+. Importantly, Gal2A exhibited high transglycosylation activity, which can catalyze the formation of GOS from milk and lactose. These characteristics indicated that Gal2A may be ideal for producing GOSs and lactose-reducing dairy products.

“…ANT48 [ 23 ], and recombinant Gal from Alteromonas sp. ML52 [ 27 ]. However, the pH stability range of Gal2A was much wider than that of BgaL [ 28 ] from Paracoccus sp.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Cloning and Characterization of a New β-Galactosidase from Alteromonas sp. QD01 and Its Potential in Synthesis of Galacto-Oligosaccharides

et al. 2020

“…Then the reaction mixture was determined at OD 420 nm according to the ONP standard curve. One unit (U) of β-galactosidase was defined as the amount of enzyme required for the liberation of 1 µmol ONP per minute under the assay conditions [47].…”

Section: Methodsmentioning

confidence: 99%

A New β-Galactosidase from the Antarctic Bacterium Alteromonas sp. ANT48 and Its Potential in Formation of Prebiotic Galacto-Oligosaccharides

Zhu

Xing

2019

As an important medical enzyme, β-galactosidases catalyze transgalactosylation to form prebiotic Galacto-Oligosaccharides (GOS) that assist in improving the effect of intestinal flora on human health. In this study, a new glycoside hydrolase family 2 (GH2) β-galactosidase-encoding gene, galA, was cloned from the Antarctic bacterium Alteromonas sp. ANT48 and expressed in Escherichia coli. The recombinant β-galactosidase GalA was optimal at pH 7.0 and stable at pH 6.6–7.0, which are conditions suitable for the dairy environment. Meanwhile, GalA showed most activity at 50 °C and retained more than 80% of its initial activity below 40 °C, which makes this enzyme stable in normal conditions. Molecular docking with lactose suggested that GalA could efficiently recognize and catalyze lactose substrates. Furthermore, GalA efficiently catalyzed lactose degradation and transgalactosylation of GOS in milk. A total of 90.6% of the lactose in milk could be hydrolyzed within 15 min at 40 °C, and the GOS yield reached 30.9%. These properties make GalA a good candidate for further applications.

“…Bioprospecting of marine Polar environments and deep-sea waters led to the identification of cold-active β-galactosidases from Alteromonas , Alkalilactibacillus , Marinomonas and Pseudoalteromonas species [ 29 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 ]. In addition, cold-active β-galactosidases were also isolated from psychrophilic and psychrotolerant microorganisms from different cold environments including Antarctic soil [ 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ], glaciers [ 64 ] and deep lakes [ 65 , 66 ].…”

Section: Sources Of Cold-active β-Galactosidasesmentioning

confidence: 99%

Cold-Active β-Galactosidases: Insight into Cold Adaptation Mechanisms and Biotechnological Exploitation

Mangiagalli

Lotti

2021

β-galactosidases (EC 3.2.1.23) catalyze the hydrolysis of β-galactosidic bonds in oligosaccharides and, under certain conditions, transfer a sugar moiety from a glycosyl donor to an acceptor. Cold-active β-galactosidases are identified in microorganisms endemic to permanently low-temperature environments. While mesophilic β-galactosidases are broadly studied and employed for biotechnological purposes, the cold-active enzymes are still scarcely explored, although they may prove very useful in biotechnological processes at low temperature. This review covers several issues related to cold-active β-galactosidases, including their classification, structure and molecular mechanisms of cold adaptation. Moreover, their applications are discussed, focusing on the production of lactose-free dairy products as well as on the valorization of cheese whey and the synthesis of glycosyl building blocks for the food, cosmetic and pharmaceutical industries.