Use of an enzymatic substance having specific glucuronan lyase activity to cleave polysaccharides of polyglucuronic/polyglucuronate acid family to give a mixture of oligoglucuronan by beta elimination

摘要

Enzymatic substance having specific glucuronan lyase activity is used to cleave polysaccharides (I) of polyglucuronic/polyglucuronate acid family to give a mixture of oligoglucuronan by beta -elimination, when the starting polysaccharide is a glucuronan homopolymer or a mixture of oligcsaccharides or a polymer containing glucuronan fragments. The oligoglucuronans and oligosaccharides on the level of each nonreducing final end have a heterocyclic ethylenic unsaturated 4-deoxy-(hex-4-ene)pyranosyluronic acid (A). Enzymatic substance having specific glucuronan lyase activity is used to cleave polysaccharides of formula (I) of the polyglucuronic/polyglucuronate acid family preferably beta (1-4) glucuronan homopolymer sequence or polymers containing glucuronan fragments with beta (1-4) sequence, to give a mixture of oligoglucuronan (containing pyranyl compounds of formula (II) and (III)) by beta -elimination, when the starting polysaccharicle is a glucuronan homopolymer or a mixture of oligosaccharides, or a polymer containing glucuronan fragments. The oligoglucuronans and oligosaccharides on the level of each nonreducing end have a heterocyclic ethylenic unsaturated 4-deoxy-(hex-4-ene)pyranosyluronic acid (A), in a purified state: having = 50 U/mg with respect to a first substrate of reference (RPa) constituted by a D-polyglucuronic acid to sequence beta (1-4) having average molecular mass 50 kDa and average acetylation rate 50-65%, and = 30 U/mg with respect to a second substrate of reference (RPb) containing a D-polyglucuronic acid to sequence beta (1-4) having average molecular mass 50 kDa and average acetylation rate 68-80%. R = H or acyl, preferably acetyl. Independent claims are included for: (1) a fungal strain to provide the enzymatic substance, preferably Trichoderma CNCM 1-3400; (2) an enzymatic substance to cleave the beta (1-4) glucuronan compounds having activity = 50 U/mg with respect to RPa, = 30 U/mg with respect to RPb and = 100 U/mg with respect to a third substrate of reference (RPC) consisting of a D-polyglucuronic acid to sequence beta (1-4) having average molecular mass 50 kDa, which is completely desacetyl and obtained from RPa or RPb by treatment with an alkali (preferably sodium or potassium hydroxide) at 50 [deg] C and pH 12, where the enzymatic substance is made up of glucuronan lyases; (3) preparation of an enzymatic substance comprising cultivating a stock on the minimal nutritive medium containing glucuronan, as a single source of carbon, preferably 0.4% p/v to produce a glucuronase lyase; collecting the stock if it develops on the minimal nutritive medium and is ready to metabolize a glucuronan by cleavage and detectable by spectrophotometry at 235 nm; and (4) a phytosanitary composition comprising a phytosanitary enzymatic substance in association with an excipient. [Image].