Degradation of Chitin and Chitosan by a Recombinant Chitinase Derived from a Virulent Aeromonas hydrophila Isolated from Diseased Channel Catfish (original) (raw)
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Bioscience, Biotechnology, and Biochemistry, 1997
A ftake-chitin degrading marine bacterium was isolated and identified as A eromonas hydrophila. This strain secreted five chitinases and an JI-N-acetylglucosaminidase. The main chitinase (Chi-A) was purified and characterized. The optimum pH of Chi-A was 5-8, and the activity was inhibited by Hg2 + and Fe 3 +. Chi-A was different from chitinases of other Aeromonas species with respect to molecular weight (62,000) and insensitivity to monoiodoacetate. The amino-terminal amino acid sequence showed extensive similarity with chitinases from Gram-negative bacteria.
Microbiology Indonesia, 2008
Chitinases (EC 3.2.1.14) are enzyme that catalyze the degradation of chitin into the monomer N-acetyl-Dglucosamine (Park et al. 1997; Yi-Wang et al. 2001). While chitosanases (EC 3.2.1.132) are glycosyl hydrolase that catalyze the degradation of chitosan into α-D-glucosamine monomers. Chitin is a linear polymer of N-acetyl-Dglucosamine units linked through α (1-4) glycosidic bonds and distributed widely in nature as the skeletal materials of crustaceans and insects (Minoru et al. 2002), and also as a cell wall component of bacteria and fungi. Chitosan is a partially or fully deacetylated chitin. The α 1.4 glycosidic bond at linear polymer of N-acetyl-D-glucosamine of chitin is very strong and the chitinase or a specific chitosanase can catalyze degradation of the bond into a simple monomer. Chitin combined with protein and (organic salt) CaCO 3 form the skeletal material of crustacean and insects and this structure is involved in self defence mechanism against pathogenic bacteria and evaporation (Yamasaki 1993). The use of protein of skeletal crustacean as a protein source in poultry feed is inhibited by chitin compounds, because the poultry's digestive tract does not produce chitinase to hydrolyze chitin. Therefore, before adding to poultry feed, the crustacean skeleton should be hydrolyzed by chitinase into simple monomers, so that poultry can then digest. Generally, bacteria use their chitinase for degrading chitin as their carbon source, but some of them use chitinases for their self defence mechanism against pathogenic microorganisms. The characterization of chitinase from some bacteria has been undertaken, for example from Bacillus
Characterization of Chitinase from the Africancatfish, Clarias Gariepinus (Burchell, 1822)
2015
Chitinases are hydrolytic enzymes that break down the glycosidic bonds in chitin. The role of Chitinases in the treatment and prevention of various diseases have been reported. They have been implicated in the human health care for the treatment of fungal infections, in Asthma and in the control of mosquito which causes the deadly malaria disease accounting for about 70% of infant mortality in Africa. Chitinase was obtained from chitinolytic bacteria inhabiting the skin and gut of the African Catfish (Clarias gariepinus). Bacterial population Isolated from catfish was screened on colloidal-chitin agar medium. The ability to produce Chitinase was determined by zones of hydrolysis produced after 96h of incubation at 37oC. Isolation of chitinase was carried out with colloidal chitin as substrate in sodium phosphate buffer. Optimum conditions were therefore ascertained at a temperature of 500C and a substrate concentration of 0.15g for chitinase produced by bacteria spp (isolate code 17...
Applied Microbiology and Biotechnology, 2014
Chitin, present in crustacean shells, insects, and fungi, is the second most plentiful natural organic fiber after wood. To effectively use chitin in a cost-saving and environmentally friendly way in aquaculture, crustacean shells (e.g., shrimp-shell meal) are supplemented into aquafeed after degradation by chemical methods. Herein, we describe a chitinase from Aeromonas veronii B565, designated ChiB565, which potently degrades shrimp-shell chitin and resists proteolysis. We isolated recombinant ChiB565 of the expected molecular mass in large yield from Pichia pastoris. ChiB565 is optimally active at pH 5.0 and 50°C and stable between pH 4.5 and 9.0 at 50°C and below. Compared with the commercial chitinase C-6137, which cannot degrade shrimp-shell chitin, ChiB565 hydrolyzes shrimp-shell chitin in addition to colloidal chitin, powdered chitin, and β-1,3-1,4-glucan. The optimal enzyme concentration and reaction time for in vitro degradation of 0.1 g of powdered shrimp shell are 30 U of ChiB565 and 3 h, respectively. A synergistic protein-release effect occurred when ChiB565 and trypsin were incubated in vitro with shrimp shells. Tilapia were fed an experimental diet containing 5 % (w/w) shrimp bran and 16.2 U/kg ChiB565, which significantly improved growth and feed conversion compared with a control diet lacking ChiB565. Dietary ChiB565 enhanced nitrogen digestibility and downregulated intestinal IL-1β expression. The immunologically relevant protective effects of dietary ChiB565 were also observed for 2 to 3 days following exposure to pathogenic Aeromonas hydrophila.
Chitinolytic enzymes, classification and applications: An Overview
Chitinases are a group of enzymes capable of degrading chitin directly into low molecular weight-products. Chitinases have been isolated from different microorganisms, such as fungi and bacteria. Chitin is an insoluble natural polymer, commonly present among crustacean. Fish scales are one of the most common sources of chitin. A Crustacean and fish scales waste are ideal as row material for chitin production. Fish scales set variety of nutrition, health care, substance-in one. About 130 million tons of fish wastes is generated each year in the (Wekipedia, 2013). More than 80.000 (Wekipedia, 2013) metric tons of chitin is obtained per year from the marine waste. Chitin is closely associated with minerals, lipids and pigments. Chitinolytic enzymes have wide range of applications such as, preparation of single cell protein, preparation of pharmaceutically important chito-oligosaccharides and N-acetyl D-glucosamine. They also play an important physiological and ecological role in ecosystems as recyclers of chitin by generating carbon and nitrogen sources. They are recently used as immuno-stimulants in fish aquaculture. In this review, the occurrence and structure of various types of chitin as well as the, sources of chitinases were discussed classification and their mode of action. Besides, the updated information about the biomedical applications of the chitinases were considered
2021
This study aimed at investigating the chitinase enzyme activity produced by chitinolytic bacteria from the skin of blue swimmer crab (Portunus pelagicus) and identification of the genus isolate. This study consists of two stages: firstly, the qualitative and quantitative activity of the chitinase enzyme; and secondly, biochemical identification of the bacteria. The quantitative chitinase enzyme activity is measured using the UV-Vis spectrophotometer UV-Vis at the wavelength at 660 nm. The chitinase enzyme is obtained from the isolation of chitinolytic bacteria cultured within a media to grow solid chitin, which contains colloidal chitin substrate as chitinase inductor at the temperature of 30°C. The highest chitinolytic activity is obtained from the 24 h supernatant culture, with a value of enzyme activity at 0.149 U/mL. Macroscopic and microscopic identification showed that the chitinolytic bacteria isolate R1, whereas the biochemical cell shows the characteristics of the genus Pse...
Journal of Bioscience and Bioengineering, 2001
A gene encoding chitinase from Aeromonas sp. no. 10S-24 was expressed using pTrc99A in Escherichla coli JM 105 which yielded a 5-fold higher activity than when pUC19 was used. Three different truncated enzymes (SA-1, SA-2 and SA-3) were obtained after purification. Their isoelectric points were 7.0, 6.9, and 6.7, respectively. The enzymes showed two optimum pHs, 4.0 and 7.0, when incubated with ethylene glycol chitin as the snbstrate, and were stable over a wide pH range (3.0-9.0). The optimum temperature was 60°C and the enzymes were stable up to 50°C. The chitinases exhibited wide substrate specificities for chitin-related compounds.
2011
Article History In the present investigation Bacillus sp. strain was isolated and screened from the red soil collected from Doiwala region of Dehradun (U.K), India. Serial dilution technique was adopted to isolate the organism and was screened for its chitinolytic activity. The biochemical tests were performed to prove its validity. The microorganism was also screened by inoculating a loop full of the isolated strain in basic cresol red dye and incubated for about 18-24 h. The conversion of colour of the red dye into purple (pH, 6.5-8.8) was taken as an indication for the presence of Bacillus sp. Amylase production by the organism was also screened by introduction of iodine in the broth/agar culture having starch. The broth/agar medium having starch but no bacterial strain was used as the control. The disappearance of color confirmed the presence of Bacillus strain producing amylase which degrades the starch. The chitinous wastes were collected from fresh water crustaceans viz. fresh water crab (Potamon sp.) and fresh water prawn (Palaemon sp.) and the chitin extracted was used as the substrate for chitinase. The yield of chitin extracted from fresh water prawn (Palaemon sp.) was found to be comparatively higher than that of chitin extracted from fresh water crab (Potamon sp.). Standard colloidal chitin was used as the reference control. The enzyme activity of chitinase for degradation of chitin extracted from crab and prawn was compared. The results confirmed that chitinase activity for degradation of crab chitin was comparatively higher than that of degradation of prawn chitin. The enzyme activities were found to be 0.11 µg/ml/minute and 0.09 µg/ml/minute for degradation of crab and prawn chitin respectively. The antimicrobial activity of chitinase extracted was determined against the bacterial and fungal cultures. Potent antibacterial activity of chitinase was observed against the bacterial cultures but no antifungal activity was observed. The chitinase produced by the species was able to degrade the chitin and chito-oligosaccharides produced was separated by TLC and purified by HPLC.