Characterization of dextransucrase from Leuconostoc mesenteroides T3, water kefir grains isolate

Abstract

The production of dextransucrase (DS) by Leuconostoc mesenteroides T3, novel isolate from water kefir grain, was studied and optimized. Bacterial supernatant reached activity of 3.1 U/ml when the culture was grown at 23 °C and under static culture condition using classical Tsuchiya medium for DS production. The increase of sucrose concentration to 7% led to an increase of DS activity by 52% compared to the control. Medium with 2% beef extract and 1% yeast extract resulted in 4.52 U/ml, which was 47% higher than in the control (with 2% yeast extract). Finally, the increase of K 2 HPO 4 concentration from 2 to 3% resulted in the increased enzyme activity by 28%. Enzyme purified by polyethylene glycol 400 fractionation displayed maximum activity at 30 °C and pH 5.4. Zymogram analysis confirmed the presence of DS of approximately 180 kDa. The addition of divalent cations Ca 2+ , Mg 2+ , Fe 2+ and Co 2+ led to a minor increase of DS activity, while the addition of Mn 2+was the most prominent with 73% increase. These findings classify dextransucrase from Leuconostoc mesenteroides T3 as promising candidate for production of dextran, which has numerous applications in various industries.Lactic acid bacteria (LAB) are one of the main classes of microorganisms that are known to produce several industrially important biomolecules among which exopolysaccharides (EPS) have the widest range of uses [1]. Fermentation processes for EPS production are quite expensive due to purification costs, giving an advantage to the use of enzymes. Current challenges in the LAB enzymes production include both strain improvement and enhancement of enzyme production.Dextransucrase (DS) is an extracellular enzyme that belongs to the class of glucosyltransferases [2] and it is mainly produced by microorganisms belonging to the families Lactobacillaceae and Streptococcaceae, especially by the genera Lactobacillus, Leuconostoc and Streptococcus [3]. Enzyme DS catalyzes the transfer reaction of glucosyl residues from sucrose to dextran polymer chain and releases fructose [4,5]. In the presence of appropriate acceptor (glucose, maltose, isomaltose, etc.) this enzyme can also produce oligosaccharides [6].

Optimization of Process Parameters for Maximum Production and Characterization of Dextransucrase From Newly Isolated Acetobacter Tropicalis

“…Some other authors have reported 180 rpm, 150 rpm and 200 rpm (Dols et al, 1998;Honorato and Rodrigues, 2010;Sawale and Lele, 2010a) for the production of dextransucrase. Contrary to above given results, L. mesenteroides T3 gave best results (3.1 U/mL) at static condition in the recent report (Miljkovic et al, 2017).…”

“…Whereas, L. mesenteroides PCSIR-3 and L. mesenteroides CMG713 dextransucrase gave best result at 26 °C and 30 o C, respectively with enzyme activity of 0.23 U/mL and 0.67 U/mL, respectively (Ul Qader et al, 2001;Sarwat et al, 2008). In the recent study, maximum activity of L. mesenteroides T3 dextransucrase (3.10 U/ml) was obtained at 23 °C (Miljkovic et al, 2017). …”

“…Purama and Goyal (2009) also reported the effect of beef extract (1.5%, w/v) on dextransucrase production from L. mesen tero ides NRRL B-64 0 b y15 %. Whereas, for L. mesenteroides T3, combination of beef extract and 1% yeast extract resulted in 4.52 U/mL dextransucrase activity ( Miljkovic et al, 2017). …”

“…Dextransucrase is an extracellular enzyme produced by various species of Streptococcus (Bailey and Oxford, 1958;Ul Qader et al, 2005), Leuconostoc (Naessens et al, 2005;Yamaner et al, 2010;Hashem et al, 2012;Miljkovic et al, 2017) and Lactobacillus (Yamaner et al, 2010;Rania et al, 2013). Other species reported for dextransucrase production are Weissella confusa, Pediococcus pentosaceus, Weissella cibaria JAG8 and Oenococcus kitaharae DSM 17330 (Yamaner et al, 2010;Patel et al, 2011;Rao and Goyal, 2013;Vuillemin et al, 2018).…”

Structural analysis and characterization of a clinically important low molecular weight natural dextran synthesized by Leuconostoc lactis KU665298 dextransucrase

“…Lactic acid bacteria have a long history of safe use in human consumption and, therefore, among variety of microorganisms, are most widely explored for the production of microbial exopolysaccharides (Nikolic et al, 2012). Fermentation processes for EPS production are quite expensive due to purification costs, giving an advantage to the use of enzymes (Miljkovic et al, 2017). Dextran, being an extensively important microbial exopolysaccharide is synthesized from sucrose by the aid of dextransucrase enzyme.…”