Chitinase biotechnology: Production, purification, and application

Abstract

Chitin is one of the most abundant biopolymers and is present in many organisms in different forms. Its resistance to degradation has caused many problems in industry (waste decomposition) and agriculture (as protective structures in pests); this has led to increased interest in chitin-hydrolyzing enzymes: chitinases. Chitinases are enzymes that break down the 1→4 β-glycoside bond of N-acetyl d-glucosamine in chitin to produce mono-and oligomers. The inducible nature of chitinases, low activity of synthesized enzymes, and inertia of the substrate are only a few of the problems that can be solved by biotechnology to meet industry demands for green, energy-efficient, pollution-free, and economically profitable chitin use. This review aims to present the pitfalls and successes in research and production of chitinolytic enzymes, as well as to promote the use of chitinases in everyday practice. The focus is on the biosynthesis of chitinases: inducers, type of fermentation, and media composition. Methods for purification and future perspectives are also discussed.

Systems analysis of the glycoside hydrolase family 18 enzymes from Cellvibrio japonicus characterizes essential chitin degradation functions

“…CjChi18A cat had an initial rate of 118 ± 1 min -1 , while CjChi18D cat and CjChi18B cat had initial rates of 44.5 ± 2.6 and 27.0 ± 0.8 min -1 , respectively. The product profile obtained for the enzymes shortly after initiation of the (GlcNAc) 6 hydrolysis reactions (2 min reaction time) showed striking differences between the chitinases (Fig. 7B).…”

“…CjChi18A cat yielded all possible product types ((GlcNAc) [1][2][3][4][5] ), where GlcNAc was the dominating product (97.8 ± 7.3 µM) followed by (GlcNAc) 2 (62.3 ± 2.5 µM), (GlcNAc) 3 (47.7 ± 1.7 µM) and (GlcNAc) 4 (33.9 ± 1.5 µM). Quantification of (GlcNAc) 5 was not possible due to co-elution with (GlcNAc) 6 . CjChi18B cat produced mainly (GlcNAc) 2 and (GlcNAc) 3 , with minor amounts of (GlcNAc) 4 .…”

“…Thus, activity towards the soluble chito-oligosaccharide (GlcNAc) 6 was determined for all four GH18 catalytic domains (Fig. 7A).…”

“…The rate of chitin degradation has been calculated to match the rate of synthesis resulting in little net accumulation of chitin in the environment, suggesting that the microorganisms that derive nutrition from this polysaccharide are able to degrade it with high efficiency (2). Moreover, chitin is increasingly being recognized as an important feedstock for the production of renewable chemicals, and chito-oligosaccharides are being investigated for several biomedical applications (3)(4)(5)(6). The strategies used by microbes for efficient chitin bioconversion are gaining interest, as current chemical methods used for the industrial processing of chitin are inefficient and wasteful (7,8).…”

“…Specifically, chitin depolymerization is achieved through a concerted effort of endo-and exo-acting enzymes to reduce polymer length to short oligosaccharides that are then converted to Nacetylglucosamine monomers by hexosaminidases for entry into cellular metabolism ( Fig. 1) (6). Additionally, the action of lytic polysaccharide monooxygenases (LPMO) in aerobic microbes promotes chitin degradation by acting on crystalline regions of the substrate (13)(14)(15).…”