Chitinases: An update

Hamid, Rifat; Khan, Minhaj Ahmad; Ahmad, Mahboob; Ahmad, Malik M.; Abdin, Malik Zainul; Musarrat, Javed; Javed, Saleem

doi:10.4103/0975-7406.106559

Cited by 344 publications

(128 citation statements)

References 120 publications

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“…When using (GlcNAc) 4 as the substrate, the product was (GlcNAc) 2 . (GlcNAc) 5 was converted into (GlcNAc) 3 and (GlcNAc) 2 . When using (GlcNAc) 6 as the substrate, (GlcNAc) 3 and (GlcNAc) 2 were generated.…”

Section: Draft Genome Analysis Of T Chitonophagus and Identification Ofmentioning

confidence: 99%

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A Structurally Novel Chitinase from the Chitin-Degrading Hyperthermophilic Archaeon Thermococcus chitonophagus

Horiuchi

Aslam

Kanai

et al. 2016

Appl Environ Microbiol

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A structurally novel chitinase, Tc-ChiD, was identified from the hyperthermophilic archaeon Thermococcus chitonophagus, which can grow on chitin as the sole organic carbon source. The gene encoding Tc-ChiD contains regions corresponding to a signal sequence, two chitin-binding domains, and a putative catalytic domain. This catalytic domain shows no similarity with previously characterized chitinases but resembles an uncharacterized protein found in the mesophilic anaerobic bacterium Clostridium botulinum. Two recombinant Tc-ChiD proteins were produced in Escherichia coli, one without the signal sequence [TcChiD(⌬S)] and the other corresponding only to the putative catalytic domain [Tc-ChiD(⌬BD)]. Enzyme assays using N-acetylglucosamine (GlcNAc) oligomers indicated that both proteins hydrolyze GlcNAc oligomers longer than (GlcNAc) 4 . Chitinase assays using colloidal chitin suggested that Tc-ChiD is an exo-type chitinase that releases (GlcNAc) 2 or (GlcNAc) 3 . Analysis with GlcNAc oligomers modified with p-nitrophenol suggested that Tc-ChiD recognizes the reducing end of chitin chains. While TcChiD(⌬BD) displayed a higher initial velocity than that of Tc-ChiD(⌬S), we found that the presence of the two chitin-binding domains significantly enhanced the thermostability of the catalytic domain. In T. chitonophagus, another chitinase ortholog that is similar to the Thermococcus kodakarensis chitinase ChiA is present and can degrade chitin from the nonreducing ends. Therefore, the presence of multiple chitinases in T. chitonophagus with different modes of cleavage may contribute to its unique ability to efficiently degrade chitin. IMPORTANCEA structurally novel chitinase, Tc-ChiD, was identified from Thermococcus chitonophagus, a hyperthermophilic archaeon. The protein contains a signal peptide for secretion, two chitin-binding domains, and a catalytic domain that shows no similarity with previously characterized chitinases. Tc-ChiD thus represents a new family of chitinases. Tc-ChiD is an exo-type chitinase that recognizes the reducing end of chitin chains and releases (GlcNAc) 2 or (GlcNAc) 3 . As a thermostable chitinase that recognizes the reducing end of chitin chains was not previously known, Tc-ChiD may be useful in a wide range of enzyme-based technologies to degrade and utilize chitin. Chitin is a ␤-1,4-linked insoluble linear polymer of N-acetylglucosamine (GlcNAc) and is the main component of the exoskeleton of crustaceans and insects, as well as the cell walls of fungi. Chitin is the second most abundant natural polysaccharide after cellulose, and its annual formation rate is in the order of 10 10 to 10 11 tons (1). At present, the majority of chitin remains unused, and thus the development of effective methods to convert chitin into useful biomaterials and/or bioenergy is important to maintain our supplies of edible polysaccharides, such as starch.Chitinases are enzymes responsible for the hydrolysis of chitin polymer, and they produce GlcNAc and/or its oligomers as products. Chitinases are found ...

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Section: Draft Genome Analysis Of T Chitonophagus and Identification Ofmentioning

confidence: 99%

“…Chitinases are found in a variety of organisms, including bacteria, archaea, fungi, viruses, animals, and plants (1,2). Chitinases from a number of bacteria have been studied in detail.…”

mentioning

confidence: 99%

A Structurally Novel Chitinase from the Chitin-Degrading Hyperthermophilic Archaeon Thermococcus chitonophagus

Horiuchi

Aslam

Kanai

et al. 2016

Appl Environ Microbiol

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“…1 The chitinases, coupled with the β-N-acetylglucosaminidase, have been used to produce Nacetyl-D-glucosamine and for the healing of ulcerative colitis and other gastrointestinal inflammations. 7 N-Acetyl-COSs, which are amino sugars, are known to have various biological functions. For instance, the chitinases have been applied for the production of N-acetylchitobiose [(GlcNAc) 2 ], which is currently used as a food supplement.…”

Section: ■ Introductionmentioning

confidence: 99%

Novel Protease-Resistant Exochitinase (Echi47) from Pig Fecal Environment DNA with Application Potentials in the Food and Feed Industries

Liu

Yan

Yang

et al. 2015

J. Agric. Food Chem.

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A novel exochitinase gene (Echi47) was directly cloned from the pig fecal environment DNA using the genomic walking PCR technique and expressed in Escherichia coli BL21 (DE3). Echi47 has an open reading frame (ORF) of 1,161 bp encoding 386 amino acids. The amino acid sequence of Echi47 showed 36% identity with that of chitinase from Coprinellus congregatus. The recombinant exochitinase was purified with specific activity toward colloidal chitin of 6.84 U/mg. Echi47 was optimally active at pH 5.0 and 40 °C, respectively. When colloidal chitin was used as substrate, N-acetylchitobiose [(GlcNAc)2] was mostly produced at the initial stage, suggesting that it is an exochitinase. Echi47 exhibited excellent resistance to pepsin, trypsin, proteinase K, and flavor protease. Under simulated alimentary tract conditions, Echi47 was stable and active, releasing 21.1 mg of N-acetylchitooligosaccharides from 80 mg of colloidal chitin. These properties make Echi47 a potential additive in the food and feed industries.

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“…Chitinases degrade chitin in the environment to supply bacteria with C and N sources as well as energy (Hamid et al 2013). Strategic tillage did not influence the abundance of Chitinase A at either soil depth, but two-time chisel tillage led to a depth effect, which was absent in one-time tillage and the NT.…”

Section: St Effects On Soil C and N Cycling Genesmentioning

confidence: 89%

“…Bacterial Chitinase (group A), encoded by Chitinase gene, is produced in abundance by a variety of bacteria, such as Streptomycetes (Hamid et al 2013). Chitinases degrade chitin in the environment to supply bacteria with C and N sources as well as energy (Hamid et al 2013).…”

Section: St Effects On Soil C and N Cycling Genesmentioning

confidence: 99%

Effects of strategic tillage and plant hormone treatments on wheat-associated microbial communities

Liu¹

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The main aim of this thesis was to characterise microbial properties of microbiomes associated with wheat (Triticum aestivum) soils and wheat plants. In particular my objective was to better understand the effects on microbial communities following strategic tillage (ST) in wheat field soils and the activation of plant defence pathways in wheat plants. Throughout the thesis, multiple culture-independent methods, especially next-generation sequencing of 16S rRNA gene were used to profile soil microbial communities. Over half of the arable land in the northern grains region of Australia is managed using no-till (NT), a farming method which has improved crop yields and soil quality while reducing the input and labour costs. However, in recent years, concerns have arisen among farmers over the weed control in continuous NT systems. Strategic tillage has been touted as a potential solution, in particular for the severe weed infestations of long-term NT. Nevertheless, there is little information on the influence of ST on the microbial properties of Australian NT soils.In the present study, ST applications and soil sampling were performed in Moonie, Moree and Condamine during the fallow period in eastern Australia. These sites were chosen based on their long history of repeated wheat cultivation under NT farming practices and their different soil types.Overall, results show that in the Moonie trial on a Calcisol, one-time ST with either chisel or offset disc did not significantly influence the composition of soil bacterial communities when measured 13 months after tillage. However, relative to the NT, chisel tillage led to significant increases in microbial biomass carbon (MBC), abundances of Alphaproteobacteria, Bacteroidetes and Firmicutes as well as the utilisation of D+cellubiose and mannitol at 0-10 cm depth. In the Moree trial on a grey Vertosol, ST with different timing and implement demonstrated great potential in weed control and did not influence wheat yield and soil physicochemical and biological properties in the short-term. In the Condamine site on a Solonetz soil, one-or two-time chisel tillage did not influence soil MBC, total microbial enzymatic activity (MEA) or utilisation of C substrates.Likewise, ST did not change the soil microbial community structure and the abundance of genes encoding enzymes involved in key steps of C and N reactions. However, one-time chisel increased relative abundance of Acidobacteria RB41 and Acidobacteria iii1-15, and two-time chisel slightly increased the average C utilisation, at 10-20 cm depth. Overall, this thesis suggests that ST does not cause major impacts on soil properties of long-term NT and could be potentially used to address the long-term NT-associated issues without impacting overall soil properties.Recent reports demonstrate the importance of microbiomes associated with plants and their soil they are cultivated in. Beneficial microbes can significantly increase crop yields and provide biocontrol functions against plant pathogens, but prior to this stu...

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Chitinases: An update

Cited by 344 publications

References 120 publications

A Structurally Novel Chitinase from the Chitin-Degrading Hyperthermophilic Archaeon Thermococcus chitonophagus

A Structurally Novel Chitinase from the Chitin-Degrading Hyperthermophilic Archaeon Thermococcus chitonophagus

Novel Protease-Resistant Exochitinase (Echi47) from Pig Fecal Environment DNA with Application Potentials in the Food and Feed Industries

Effects of strategic tillage and plant hormone treatments on wheat-associated microbial communities

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