Identification and Characterization of Three Chitinases with Potential in Direct Conversion of Crystalline Chitin into N,N′-diacetylchitobiose

Abstract

Chitooligosaccharides (COSs) have been widely used in agriculture, medicine, cosmetics, and foods, which are commonly prepared from chitin with chitinases. So far, while most COSs are prepared from colloidal chitin, chitinases used in preparing COSs directly from natural crystalline chitin are less reported. Here, we characterize three chitinases, which were identified from the marine bacterium Pseudoalteromonas flavipulchra DSM 14401T, with an ability to degrade crystalline chitin into (GlcNAc)2 (N,N’-diacetylchitobiose). Strain DSM 14401 can degrade the crystalline α-chitin in the medium to provide nutrients for growth. Genome and secretome analyses indicate that this strain secretes six chitinolytic enzymes, among which chitinases Chia4287, Chib0431, and Chib0434 have higher abundance than the others, suggesting their importance in crystalline α-chitin degradation. These three chitinases were heterologously expressed, purified, and characterized. They are all active on crystalline α-chitin, with temperature optima of 45–50 °C and pH optima of 7.0–7.5. They are all stable at 40 °C and in the pH range of 5.0–11.0. Moreover, they all have excellent salt tolerance, retaining more than 92% activity after incubation in 5 M NaCl for 10 h at 4 °C. When acting on crystalline α-chitin, the main products of the three chitinases are all (GlcNAc)2, which suggests that chitinases Chia4287, Chib0431, and Chib0434 likely have potential in direct conversion of crystalline chitin into (GlcNAc)2.

Endochitinase and Chitobiosidase Production by Marine Aeromonas caviae CHZ306: Establishment of Nitrogen Supplementation

“…Actually, (GlcNAc) 2 ( N , N ’-diacetyl-chitobiose) has significant relevance to the biotechnological, pharmaceutical, cosmetic, food, and agriculture industries due to its wide range of biological activities [ 7 , 10 ]. In this sense, (GlcNAc) 2 can be used as a cosmetic ingredient due to its high solubility and as a building block for polysaccharide synthesis [ 7 , 11 ]. From an economic perspective, the market price of (GlcNAc) 2 is approximately US $2000 per g, thus representing about 10,000 times more than GlcNAc [ 12 ].…”

Identification of the Function of the Pathogenesis-Related Protein GmPR1L in the Resistance of Soybean to Cercospora sojina Hara

“…Plant PR1 genes are polygenic; however, only some genes participate in disease resistance. A study reported that only the VvPR1b1 gene in grape plants was involved in the resistance to P. syringae pv.tabaci [ 14 ]. Bonasera et al [ 15 ] transferred PR-1a , PR-1b , and PR-1c into apple seedlings and found no disease resistance.…”

Biochemical purification and characterization of a truncated acidic, thermostable chitinase from marine fungus for N-acetylglucosamine production

“…Colloidal chitin is usually produced by processing chitin with concentrated acids to destroy the crystalline structure and enhance the approach of chitin to chitinase and lytic polysaccharide monooxygenases. Therefore, colloidal chitin is commonly applied as the substrate for chitinase to prepare COSs and GlcNAc ( Ren et al, 2022 ). Meanwhile, resources of ocean-derived chitin contain about 3% NaCl.…”

“…Marine chitinases possess higher pH and salinity tolerance than chitinases from terrestrial organisms ( Han et al, 2009 ). These chitinases exist in the marine bacteria Pseudoalteromonas flavipulchra DSM 14401 ( Ren et al, 2022 ) and the Paenibacillus strain UMBR 0002 ( Liu et al, 2020 ). Researchers have identified chitinases produced by more than 30 marine bacteria ( Xinyue et al, 2021 ), but few studies have investigated chitinase in marine fungus.…”