Characterization of a bifunctional alginate lyase as a new member of the polysaccharide lyase family 17 from a marine strain BP-2

Abstract

ObjectivesBifunctional alginate lyase can efficiently saccharify alginate biomass and prepare functional oligosaccharides of alginate.ResultsA new BP-2 strain that produces alginate lyase was screened and identified from rotted Sargassum. A new alginate lyase, Alg17B, belonging to the polysaccharide lyase family 17, was isolated and purified from BP-2 fermentation broth by freeze-drying, dialysis, and ion exchange chromatography. The enzymatic properties of the purified lyase were investigated. The molecular weight of Alg17B was approximately 77 kDa, its optimum reaction temperature was 40–45 °C, and its optimum reaction pH was 7.5–8.0. The enzyme was relatively stable at pH 7.0–8.0, with a temperature range of 25–35 °C, and the specific activity of the purified enzyme reached 4036 U/mg. A low Na+ concentration stimulated Alg17B enzyme activity, but Ca2+, Zn2+, and other metal ions inhibited it. Substrate specificity analysis, thin-layer chromatography, and mass spectrometry showed that Alg17B is an alginate lyase that catalyses the hydrolysis of sodium alginate, polymannuronic acid (polyM) and polyguluronic acid to produce monosaccharides and low molecular weight oligosaccharides. Alg17B is also bifunctional, exhibiting both endolytic and exolytic activities toward alginate, and has a wide substrate utilization range with a preference for polyM.ConclusionsAlg17B can be used to saccharify the main carbohydrate, alginate, in the ethanolic production of brown algae fuel as well as in preparing and researching oligosaccharides.

Expression and Characterization of a Cold-Adapted Alginate Lyase with Exo/Endo-Type Activity from a Novel Marine Bacterium Alteromonas portus HB161718T

“…The product distribution of Alg2951 was similar to the other enzymes, which also exhibited dual endo-/exo-type activity. For example, PL17 family enzyme Alg17B from a marine strain BP-2 degraded alginate to produce oligosaccharides with DP of 2–6, and the main product was a monosaccharide [ 37 ], the PL17 family enzyme AlgSH17 from Microbulbifer sp. SH-1 also degraded alginate to produce a monosaccharide with small amounts of oligosaccharides with DP 2–6 [ 38 ], and the PL15 family alginate lyase from Sphingomonas sp.…”

Cellulose induced protein 1 (Cip1) from Trichoderma reesei enhances the enzymatic hydrolysis of pretreated lignocellulose

“…Polysaccharide lyase could catalyze depolymerization reaction through β-elimination, forming Δ-4,5-unsaturated ends, resulting in the increase of absorbance at 235 nm [ 20 – 22 ]. The lyase activity of Cip1 was determined by measuring the absorbance of supernatant at 235 nm after hydrolysis.…”

How alginate lyase produces quasi-monodisperse oligosaccharides: a normal mode analysis-based docking and molecular dynamics simulation study

“…Alginates are degraded by the so-called alginate lyases that catalyze the degradation of by the mechanism of β-elimination of glycosidic bonds, producing unsaturated oligosaccharides with an uronic acid moiety at the non-reducing terminal [1]. Over the past decades, thousands of alginate lyases have been identified as capable of degrading and modifying the fine structure of alginates to produce a variety of alginate oligosaccharides with potential antioxidant, antipathogenic, antiinflammatory and other bioactive properties as well as the biofuel sources [2,3]. Alginate lyases are currently classified into 12 polysaccharides lyases (PL) families (PL5, PL6, PL7, PL14, PL15, PL17, PL18, PL31, PL32, PL34, PL36 and PL39) in CAZy database [4], according to their sequence similarity, domain functionality and substrate specificity [5][6][7].…”