Английская Википедия:Curdlan
Curdlan is a water-insoluble linear beta-1,3-glucan, a high-molecular-weight polymer of glucose. Curdlan consists of β-(1,3)-linked glucose residues and forms elastic gels upon heating in aqueous suspension. It was reported to be produced by Alcaligenes faecalis var. myxogenes.[1] Subsequently, the taxonomy of this non-pathogenic curdlan-producing bacterium has been reclassified as Agrobacterium species.[2]
Extracellular and capsular polysaccharides are produced by a variety of pathogenic and soil-dwelling bacteria. Curdlan is a neutral β-(1,3)-glucan, perhaps with a few intra- or interchain 1,6-linkages, produced as an exopolysaccharide by soil bacteria of the family Rhizobiaceae.[3] Four genes required for curdlan production have been identified in Agrobacterium sp. ATCC31749, which produces curdlan in extraordinary amounts, and Agrobacterium tumefaciens.[4] A putative operon contains crdS (Q9X2V0, family GT2, Шаблон:Pfam), encoding β-(1,3)-glucan synthase catalytic subunit,[5] flanked by two additional genes. A separate locus contains a putative regulatory gene, Шаблон:Not a typo. A membrane-bound phosphatidylserine synthase, encoded by Шаблон:Not a typo, is also necessary for maximal production of curdlan of high molecular mass. Nitrogen starvation upregulates the curdlan operon and increases the rate of curdlan synthesis.[6]
Curdlan has numerous applications as a gelling agent in the food, construction, and pharmaceutical industries and has been approved as a food additive by the U. S. Food and Drug Administration.[7] Its use is being evaluated in fat replacement studies in foodstuffs such as sausages, meat patties and other meat products [8]
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