In:
Applied and Environmental Microbiology, American Society for Microbiology, Vol. 76, No. 24 ( 2010-12-15), p. 8211-8221
Abstract:
By targeted deletion of the polyglutamate operon ( pga ) in Bacillus licheniformis F11, a derivative form, F11.1 (Δ pga ), was obtained that, along with lacking polyglutamate (PGA) formation, displayed enhanced proteolytic activities. The phenotypic properties were maintained in a strain in which the chiBA operon was additionally deleted: F11.4 (Δ chiBA Δ pga ). These genetically modified strains, carrying the Δ pga deletion either alone (F11.1) or together with the Δ chiBA (F11.4) deletion, were used in fermentations (20-liter scale) aiming at the deproteinization of shrimp shells in order to obtain long-chain chitin. After chemical deacetylation, the resulting chitosan samples were analyzed by nuclear magnetic resonance spectroscopy, size exclusion chromatography, and viscometry and compared to a chitosan preparation that was produced in parallel by chemical methods by a commercial chitosan supplier (GSRmbH). Though faint lipid impurities were present in the fermented polysaccharides, the viscosity of the material produced with the double-deletion mutant F11.4 (Δ pga Δ chiBA ) was higher than that of the chemically produced and commercially available samples (Cognis GmbH). Thus, enhanced proteolytic activities and a lack of chitinase activity render the double mutant F11.4 a powerful tool for the production of long-chain chitosan.
Type of Medium:
Online Resource
ISSN:
0099-2240
,
1098-5336
DOI:
10.1128/AEM.01404-10
Language:
English
Publisher:
American Society for Microbiology
Publication Date:
2010
detail.hit.zdb_id:
223011-2
detail.hit.zdb_id:
1478346-0
SSG:
12
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