Physicochemical properties of No.1 - No.6 lacquer berries were investigated from different origins. The Japan Showafuku (No.1) was the best cultivar of Rhus succedaneum, the size of the berry of it was near 3 -?4 fold...Physicochemical properties of No.1 - No.6 lacquer berries were investigated from different origins. The Japan Showafuku (No.1) was the best cultivar of Rhus succedaneum, the size of the berry of it was near 3 -?4 folds, which was bigger than the Chinese cultivars (No.4 - No.6) of Rhus vernicifera et al. It had more than 5% ~ 10% of lacquer wax in pericard, and contained less than 6% - 8% of lacquer oil in seed. No.1 had lower acid value (A.V) and iodine value (I.V);the key factors for this were cultivar and its growing environment. The principal constituents of lacquer waxes of No.1?- No.6 were triglycerides of fatty acids with total saturated fatty acids (TSFA) of 75% - 82.7%, total unsaturated fatty acids (TUSFA) of 15.1% - 20%, and total dibasic acids (TDBA) of 5%. The CIEL a b system and Hunter whiteness formula were used to evaluate the bleaching effect on lacquer wax by physical adsorption and ultraviolet (UV) irradiation. The optimal conditions of physical decoloration were determined for activated carbon: kieselguhr = 3:2 (g/g) as adsorbent, a ratio of 1:20 (g/mL) for lacquer wax to petroleum ether, bleaching 30 min at 80?C. UV light achieved a good bleaching effect irradiated at 60?C for 60 hrs. UV irradiation definitely changed relative contents of fatty acids, TUSFA and TDBA decreased from 19.617% to 11.022% and 4.379% to 2.017% respectively, while TSFA could be raised from 76.462% to 86.077%, however, the mechanism of UV irradiation was still unclear and should be investigated in the future.展开更多
Kinetic experiments were performed to study the effects of Pd2+ ion on the oxidation of 5,6-dibro-mo-2,3-dicyanohydroquinone catalyzed by Rhus vernicifera laccase under condition of pH 4.5 and 30 × 0. 1℃ . The ... Kinetic experiments were performed to study the effects of Pd2+ ion on the oxidation of 5,6-dibro-mo-2,3-dicyanohydroquinone catalyzed by Rhus vernicifera laccase under condition of pH 4.5 and 30 × 0. 1℃ . The results showed that the mixed activation could be observed when Pd2+ ion was at low concentrations. The competitive and non-competitive activation constants were 9 × 10 and 2 × 10-6 mol/L, respectively. With the increase of Pd2+ ion concentration, the activation was gradually converted into mixed inhibition, and the competitive and non-competitive inhibition constants were 6 × 10-6 and 32 × 10-6 mol/L, respectively.展开更多
It is studied that Rhus vernicifera laccase catalyzed oxidation of 26 disubstituted ferrocene and its metal complexes, π-arene-π-cyclopentadienyliron derivatives and metal meso-(tetra-4-sulfanatophenyl)porphyrin in ...It is studied that Rhus vernicifera laccase catalyzed oxidation of 26 disubstituted ferrocene and its metal complexes, π-arene-π-cyclopentadienyliron derivatives and metal meso-(tetra-4-sulfanatophenyl)porphyrin in the diethylene glycol monobutyl ether (DGBE)/phosphate buffer (V/V, 1/5). It is found that 1,1′-bishydroxylmethyl ferrocene etc 16 compounds are new substrates of laccase. The relation of structure and function of substrates is discussed. The affective factors of laccase-catalyzed oxidation of 1,1′-bishydroxyl-methyl ferrocene—pH, temperature, substrate concentration, laccase quantity and surfactant were investigated further.展开更多
文摘Physicochemical properties of No.1 - No.6 lacquer berries were investigated from different origins. The Japan Showafuku (No.1) was the best cultivar of Rhus succedaneum, the size of the berry of it was near 3 -?4 folds, which was bigger than the Chinese cultivars (No.4 - No.6) of Rhus vernicifera et al. It had more than 5% ~ 10% of lacquer wax in pericard, and contained less than 6% - 8% of lacquer oil in seed. No.1 had lower acid value (A.V) and iodine value (I.V);the key factors for this were cultivar and its growing environment. The principal constituents of lacquer waxes of No.1?- No.6 were triglycerides of fatty acids with total saturated fatty acids (TSFA) of 75% - 82.7%, total unsaturated fatty acids (TUSFA) of 15.1% - 20%, and total dibasic acids (TDBA) of 5%. The CIEL a b system and Hunter whiteness formula were used to evaluate the bleaching effect on lacquer wax by physical adsorption and ultraviolet (UV) irradiation. The optimal conditions of physical decoloration were determined for activated carbon: kieselguhr = 3:2 (g/g) as adsorbent, a ratio of 1:20 (g/mL) for lacquer wax to petroleum ether, bleaching 30 min at 80?C. UV light achieved a good bleaching effect irradiated at 60?C for 60 hrs. UV irradiation definitely changed relative contents of fatty acids, TUSFA and TDBA decreased from 19.617% to 11.022% and 4.379% to 2.017% respectively, while TSFA could be raised from 76.462% to 86.077%, however, the mechanism of UV irradiation was still unclear and should be investigated in the future.
基金Natural Science Foundation of Guangxi (No.9743018)
文摘 Kinetic experiments were performed to study the effects of Pd2+ ion on the oxidation of 5,6-dibro-mo-2,3-dicyanohydroquinone catalyzed by Rhus vernicifera laccase under condition of pH 4.5 and 30 × 0. 1℃ . The results showed that the mixed activation could be observed when Pd2+ ion was at low concentrations. The competitive and non-competitive activation constants were 9 × 10 and 2 × 10-6 mol/L, respectively. With the increase of Pd2+ ion concentration, the activation was gradually converted into mixed inhibition, and the competitive and non-competitive inhibition constants were 6 × 10-6 and 32 × 10-6 mol/L, respectively.
基金Supported by the National Natural Science Foundation of China(39170 2 0 3)
文摘It is studied that Rhus vernicifera laccase catalyzed oxidation of 26 disubstituted ferrocene and its metal complexes, π-arene-π-cyclopentadienyliron derivatives and metal meso-(tetra-4-sulfanatophenyl)porphyrin in the diethylene glycol monobutyl ether (DGBE)/phosphate buffer (V/V, 1/5). It is found that 1,1′-bishydroxylmethyl ferrocene etc 16 compounds are new substrates of laccase. The relation of structure and function of substrates is discussed. The affective factors of laccase-catalyzed oxidation of 1,1′-bishydroxyl-methyl ferrocene—pH, temperature, substrate concentration, laccase quantity and surfactant were investigated further.
