AUTHOR=Cui Dandan , Yang Jin , Lu Bosi , Shen Hong 

TITLE=Efficient Preparation of Chitooligosaccharide With a Potential Chitosanase Csn-SH and Its Application for Fungi Disease Protection

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.682829

DOI=10.3389/fmicb.2021.682829

ISSN=1664-302X

ABSTRACT=<p>Chitosanase plays a vital role in bioactive chitooligosaccharide preparation. Here, we characterized and prepared a potential GH46 family chitosanase from <italic>Bacillus atrophaeus</italic> BSS. The purified recombinant enzyme Csn-SH showed a molecular weight of 27.0 kDa. Csn-SH displayed maximal activity toward chitosan at pH 5.0 and 45°C. Thin-layer chromatography and electrospray ionization–mass spectrometry indicated that Csn-SH mainly hydrolyzed chitosan into (GlcN)<sub>2</sub>, (GlcN)<sub>3</sub>, and (GlcN)<sub>4</sub> with an endo-type cleavage pattern. Molecular docking analysis demonstrated that Csn-SH cleaved the glycoside bonds between subsites −2 and + 1 of (GlcN)<sub>6</sub>. Importantly, the chitosan hydrolysis rate of Csn-SH reached 80.57% within 40 min, which could reduce time and water consumption. The hydrolysates prepared with Csn-SH exhibited a good antifungal activity against <italic>Magnaporthe oryzae</italic> and <italic>Colletotrichum higginsianum</italic>. The above results suggested that Csn-SH could be used to produce active chitooligosaccharides efficiently that are biocontrol agents applicable for safe and sustainable agricultural production.</p>