Production, Purification, Immobilization, and Characterization of a Thermostable β-Galactosidase from Aspergillus alliaceus

Abstract

A fungal strain isolated from rotten banana and identified as Aspergillus alliaceus was found capable of producing thermostable extracellular β-galactosidase enzyme. Optimum cultural conditions for β-galactosidase production by A. alliaceus were as follows: pH 4.5; temperature, 30 °C; inoculum age, 25 h; and fermentation time, 144 h. Optimum temperature, time, and pH for enzyme substrate reaction were found to be 45 °C, 20 min, and 7.2, respectively, for crude and partially purified enzyme. For immobilized enzyme-substrate reaction, these three variable, temperature, time, and pH were optimized at 50 °C, 40 min, and 7.2, respectively. Glucose was found to inhibit the enzyme activity. The K(m) values of partially purified and immobilized enzymes were 170 and 210 mM, respectively. Immobilized enzyme retained 43 % of the β-galactosidase activity of partially purified enzyme. There was no significant loss of activity on storage of immobilized beads at 4 °C for 28 days. Immobilized enzyme retained 90 % of the initial activity after being used four times.

Recombinant Aspergillus β-galactosidases as a robust glycomic and biotechnological tool

“…Since various galactosidases were shown to be sensitive to the presence of divalent metal cations (Tanaka et al 1975; Sen et al 2012), we evaluated the influence of selected metal ions on the activity of recombinant Aspergillus galactosidases. Using PNPG assays supplemented with different metal ions, we found no clear impact of these ions on the activity of the studied galactosidases (Online Resource 1, Supplemental Fig.…”

“…They can be purified at high yields directly from fungal organisms (Tanaka et al 1975; Husain 2010; Sen et al 2012) or produced in a recombinant form at high levels in different expression systems (Wang et al 2009; Oliveira et al 2011). Other commonly used sources of β-galactosidases include bacteria (e.g., bifidobacteria (Hung et al 2001; Hsu et al 2005) and Streptococcus pneumonia (Hughes and Jeanloz 1964)), yeasts (e.g., Kluyveromyces lactis (Dickson and Markin 1978)), plants (e.g., from jack bean (Arakawa et al 1974; Li et al 1975)), and animals (e.g., bovine testes β-galactosidase (Distler and Jourdian 1973)).…”

“…In 2008, two β-galactosidases secreted by Aspergillus carbonarius ATCC6276 were purified to homogeneity and were shown to be resilient to simulated gastric conditions (O’Connell and Walsh 2008). Most recently, a β-galactosidase was purified from Aspergillus alliaceus and partially characterized; this enzyme, unlike various other fungal galactosidases, has a pH optimum in the neutral range, an enzymatic property suitable for the preparation of low-lactose milk (Sen et al 2012). …”

Characterization of a thermostable recombinant β-galactosidase from a thermophilic anaerobic bacterial consortium YTY-70

“…The activity level of b-galactosidases, produced from Caldicellulosiruptor, was greater than that of the majority of enzymes produced from other sources.The activity of b-galactosidase from K. lactis lost half of its maximum value for 17.5 min at 30 C and for less than 1 min at temperatures above 45 C. [31] In another study, b-galactosidase, produced from K. lactis decreased its catalytic activity by 73% at 60 C. [32] b-Galactosidase from Aspergillus alliaceus retained 82% of its enzyme activity at 70 C, compared to the maximum value. [33] Compared to other thermostable b-galactosidases, this recombinant b-galactosidase showed considerable thermal stability over a broad temperature range (between 50 and 90 C). As we know, there are many benefits when reactions are catalysed at elevated temperatures, such as improved reaction kinetics and increased substrate solubility.…”

Determination of Cell Permeabilization and Beta-Galactosidase Extraction from Aspergillus oryzae CCT 0977 Grown in Cheese Whey

“…Panesar et al [13] used some salts, lactose, peptone and yeast extract and obtained a maximum activity of the Aspergillus oryzae NCIM 1212 beta-galactosidase of 0.50 U·mL −1 , at a temperature between 45 and 50°C, a value similar to that obtained in the present study. Senm et al [14], under submerged fermentation at pH 4.5 with Aspergillus alliaceus, obtained an enzymatic activity of 0.0486 U/mL. e coefficient of determination R 2 of the model was 0.81266, which indicated that the model adequately represented the real relationship between the variables under consideration.…”