The estimation of chitin and chitin nitrogen in crawfish waste and derived products

Black, M.M.; Schwartz, Herbert M.

doi:10.1039/an9507500185

Cited by 83 publications

(43 citation statements)

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“…Chitin nitrogen was measured and calculated as described previously (1). The protein content of the dried material was measured after hydrolyzing the shrimp shell protein with 1 M NaOH at 55°C for 24 h (15).…”

Section: Methodsmentioning

confidence: 99%

Isolation and Molecular Characterization of Chitinase-Deficient Bacillus licheniformis Strains Capable of Deproteinization of Shrimp Shell Waste To Obtain Highly Viscous Chitin

Waldeck

Daum

Bisping

et al. 2006

Appl Environ Microbiol

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Proteolytic but chitinase-deficient microbial cultures were isolated from shrimp shell waste and characterized. The most efficient isolate was found to be a mixed culture consisting of two Bacillus licheniformis strains, which were first determined microscopically and physiologically. Molecular characterization was carried out by sequencing the 16S rRNA gene of both strains. According to the residual protein and ash content, the chitin obtained by fermentation of such a mixed culture was found to be comparable to a commercially available, chemically processed product. However, the strikingly high viscosity (80 versus 10 mPa of the commercially available sample) indicates its superior quality. The two strains differed in colony morphology and in their secretion capabilities for degradative extracellular enzymes. Sequencing of the loci encoding amylase, cellulase, chitinases, and proteases, as well as the degS/degU operon, which is instrumental in the regulation of degradative enzymes, and the pga operon, which is responsible for polyglutamic acid production, revealed no differences. However, a frameshift mutation in chiA, encoding a chitinase, was validated for both strains, providing an explanation for the ascertained absence of chitinolytic activities and the concomitant possibility of producing highly viscous chitin in a fermentational deproteinization process.Chitin (a polysaccharide consisting of ␤-1,4-linked N-acetyl-D-glucosamine moieties) is the second most abundant biopolymer on earth; thus, it represents a nearly constant source of renewable raw material. Along with its deacetylated derivative chitosan, chitin recently has gained biotechnological significance, not only because of favorable pharmaceutical features, such as antimicrobial, anticholesterol, and antitumor activities, but also because of its potential for wastewater treatment, drug delivery, and wound healing and as a dietary fiber (26).Approximately 50 to 60% of the total weight of shellfish, such as shrimp, crab, and krill, consists of nonedible material, i.e., "heads" and exoskeletons rich in chitin but also protein, which form, on the one hand, major environmental pollutants as a result of uncontrolled dumping (12). On the other hand, however, due to their chemical composition (20 to 30% chitin, 20 to 40% protein, 30 to 60% minerals, and 0 to 14% lipids) and their actual availability from seafood industries, shrimp waste also constitutes the major source for chitin and chitosan production (21). Currently applied methods to purify and modify chitin from such material and to transform it to useful carbohydrate products involve harsh chemical treatments accompanied by uncontrollable hydrolysis and chemical modifications that eventually result in the formation of undesired by-products such as irregularly deacetylated polymers (33).Exploitation limits are mainly set by the purification costs, which mainly arise from removal of proteins and calcium carbonate by alternating acid and alkali treatment, ultimately resulting in large amounts of aque...

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Section: Methodsmentioning

confidence: 99%

Isolation and Molecular Characterization of Chitinase-Deficient Bacillus licheniformis Strains Capable of Deproteinization of Shrimp Shell Waste To Obtain Highly Viscous Chitin

Waldeck

Daum

Bisping

et al. 2006

Appl Environ Microbiol

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“…of chitin by crude fibre analysis was considered a reliable method (Black & Schwartz, 1950). Besides chitin, shrimp meal contains high portions of protein and ash.…”

Section: Determinationmentioning

confidence: 99%

Effects of fibre on digestibility and passage time in Callithricidae

Krombach¹,

Flurer

Zücker

1984

Lab Anim

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275 SummaryThe effects of fibre in a pelleted diet on food intake, digestibility of crude fibre, dry matter and energy, on passage time and consistency of faeces were studied in 2 species of Callithricidae, Ca/lilhrix jacchus and Saguinus juscicollis. Coarse cellulose, microcellulose, wheat bran and shrimp meal (chitin = crude fibre) were tested in diets containing 2, 4 and 6% total crude fibre, respectively. Digestibility and passage time were determined by inclusion of 0'5% Cr203 in the diet.Both celluloses had little influence on the digestibility of energy and dry matter. Digestibility of crude fibre was very low. Wheat bran led to evident depression of energy and dry matter digestibility. High digestibility of crude fibre occurred at the higher levels of inclusion in the diet. Shrimp meal was highly digested with little innuence on digestibility of energy and dry matter, indicating considerable degradation of chitin. Wheat bran showed a marked effect, while microcellulose had no effect on passage time, consistency and volume of faeces.

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“…Crude protein was calculated by multiplying nitrogen content of the sample by 6.25. Chitin was determined by the method of Black and Schwartz (1950). All analyses were performed in triplicate.…”

Section: Chemical Composition Of Crab Shellmentioning

confidence: 99%

Physicochemical and functional properties of chitosans prepared from shells of crabs harvested in three different years

Youn

Prinyawiwatkul

2009

Carbohydrate Polymers

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The estimation of chitin and chitin nitrogen in crawfish waste and derived products

Cited by 83 publications

References 0 publications

Isolation and Molecular Characterization of Chitinase-Deficient Bacillus licheniformis Strains Capable of Deproteinization of Shrimp Shell Waste To Obtain Highly Viscous Chitin

Isolation and Molecular Characterization of Chitinase-Deficient Bacillus licheniformis Strains Capable of Deproteinization of Shrimp Shell Waste To Obtain Highly Viscous Chitin

Effects of fibre on digestibility and passage time in Callithricidae

Physicochemical and functional properties of chitosans prepared from shells of crabs harvested in three different years

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