pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, bat...pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, batch experiments were conducted at fixed pH value （pH 5-9） with or without acetate （20 g/L）. The hydrolysis efficiencies of carbohydrate and protein were evaluated by carbon and nitrogen content of solids, amylase activity and proteinase activity. The trend of carbohydrate hydrolysis with pH was not affected by the addition of acetate, following the sequence ofpH 7〉pH 8〉pH 9〉pH 6〉pH 5; but the inhibition of acetate （20 g/L） was obvious by 10%-60 %. The evolution of residual nitrogen showed that the effect of pH on protein hydrolysis was minor, while the acetate was seriously inhibitory especially at alkali condition by 45%-100 %. The relationship between the factors （pH and acetate） and the response variables was evaluated by partial least square modeling （PLS）. The PLS analysis demonstrated that the hydrolysis of carbohydrate was both affected by pH and acetate, with pH the more important factor. Therefore, the inhibition by acetate on carbohydrate hydrolysis was mainly due to the corresponding decline of pH, but the presence of acetate species, while the acetate species was the absolutely important factor for the hydrolysis of protein.展开更多
The method for preparing low molecular weight fucosylated chondroitin sulfate from sea cucumber lsostichopus badionotus using partial acid hydrolysis was reported, and its hydrolysis mechanism was also investigated. T...The method for preparing low molecular weight fucosylated chondroitin sulfate from sea cucumber lsostichopus badionotus using partial acid hydrolysis was reported, and its hydrolysis mechanism was also investigated. The sea cucumber chondroitin sulfate FCS was hydrolyzed under different conditions （80℃3 h and 6 h）, then isolated and purified on a Bio-P-4 geltration to prepare low molecular weight fractions （LMWF-FCS）. The chemical compositions of LMWF-FCS showed the branched fucose （Fuc） was cleaved during acid hydrolysis process, whereas the mole ratio of acetyl-galactosamine （GalNAc） and glucuronic acid （GlcA） in the backbone remained the same, which indicated the backbone was a typical chondroitin sulfate structure. The disaccharide composition analysis of LMWF-FCS suggested that the sulfation patterns of GalNAc in the backbone chain changed and the substitution value was reduced. Furthermore, the 1D NMR analysis illustrated the branched-Fuc was cleaved during acid hydrolysis, but their substitution patterns were not influenced, which was distinct from the previous reports that the substitutions of branched-Fuc in FCS were easy to change. Simultaneously, the sulfation pattern of GalNAc in backbone chain changed obviously in the acid hydrolysis process. The anticoagulant activity in vitro illuminated the anticoagulant activity of the degradation products over time in the acid hydrolysis are gradually declined, but still kept good. Therefore, the LMWF-FCS prepared could be developed as a new anticoagulant and antithrombotic drug like low molecular weight heparin.展开更多
以野菊花为原材料,经热水提取、乙醇沉淀、DEAE-Sepharose Fast Flow和Sephacryl S-200凝胶柱层析分离纯化,得到1个水溶性的中性多糖CIP-C.采用GC-MS、部分酸水解及甲基化分析等对该多糖的结构进行了解析.结果表明,该多糖主要由D-Man,D-...以野菊花为原材料,经热水提取、乙醇沉淀、DEAE-Sepharose Fast Flow和Sephacryl S-200凝胶柱层析分离纯化,得到1个水溶性的中性多糖CIP-C.采用GC-MS、部分酸水解及甲基化分析等对该多糖的结构进行了解析.结果表明,该多糖主要由D-Man,D-Glc和D-Gal组成,并含有少量的D-Fuc,L-Ara和D-Xyl,其主链由β(或α)-D-1,4-Man,β-D-1,6-Glc和β-D-1,4-Gal组成,而阿拉伯糖通过α-L-T-Araf和α-L-1,5-Araf连接形成阿拉伯聚糖支链或与β-D-1,4-Galp的O3位相连形成阿拉伯半乳聚糖支链.展开更多
文摘pH and volatile fatty acids both might affect the further hydrolysis of particulate solid waste, which is the limiting-step of anaerobic digestion. To clarify the individual effects of pH and volatile fatty acids, batch experiments were conducted at fixed pH value （pH 5-9） with or without acetate （20 g/L）. The hydrolysis efficiencies of carbohydrate and protein were evaluated by carbon and nitrogen content of solids, amylase activity and proteinase activity. The trend of carbohydrate hydrolysis with pH was not affected by the addition of acetate, following the sequence ofpH 7〉pH 8〉pH 9〉pH 6〉pH 5; but the inhibition of acetate （20 g/L） was obvious by 10%-60 %. The evolution of residual nitrogen showed that the effect of pH on protein hydrolysis was minor, while the acetate was seriously inhibitory especially at alkali condition by 45%-100 %. The relationship between the factors （pH and acetate） and the response variables was evaluated by partial least square modeling （PLS）. The PLS analysis demonstrated that the hydrolysis of carbohydrate was both affected by pH and acetate, with pH the more important factor. Therefore, the inhibition by acetate on carbohydrate hydrolysis was mainly due to the corresponding decline of pH, but the presence of acetate species, while the acetate species was the absolutely important factor for the hydrolysis of protein.
基金Sponsored by the National Natural Sciences Foundation of China(Nos.30871944 and 30971923)
文摘The method for preparing low molecular weight fucosylated chondroitin sulfate from sea cucumber lsostichopus badionotus using partial acid hydrolysis was reported, and its hydrolysis mechanism was also investigated. The sea cucumber chondroitin sulfate FCS was hydrolyzed under different conditions （80℃3 h and 6 h）, then isolated and purified on a Bio-P-4 geltration to prepare low molecular weight fractions （LMWF-FCS）. The chemical compositions of LMWF-FCS showed the branched fucose （Fuc） was cleaved during acid hydrolysis process, whereas the mole ratio of acetyl-galactosamine （GalNAc） and glucuronic acid （GlcA） in the backbone remained the same, which indicated the backbone was a typical chondroitin sulfate structure. The disaccharide composition analysis of LMWF-FCS suggested that the sulfation patterns of GalNAc in the backbone chain changed and the substitution value was reduced. Furthermore, the 1D NMR analysis illustrated the branched-Fuc was cleaved during acid hydrolysis, but their substitution patterns were not influenced, which was distinct from the previous reports that the substitutions of branched-Fuc in FCS were easy to change. Simultaneously, the sulfation pattern of GalNAc in backbone chain changed obviously in the acid hydrolysis process. The anticoagulant activity in vitro illuminated the anticoagulant activity of the degradation products over time in the acid hydrolysis are gradually declined, but still kept good. Therefore, the LMWF-FCS prepared could be developed as a new anticoagulant and antithrombotic drug like low molecular weight heparin.
文摘以野菊花为原材料,经热水提取、乙醇沉淀、DEAE-Sepharose Fast Flow和Sephacryl S-200凝胶柱层析分离纯化,得到1个水溶性的中性多糖CIP-C.采用GC-MS、部分酸水解及甲基化分析等对该多糖的结构进行了解析.结果表明,该多糖主要由D-Man,D-Glc和D-Gal组成,并含有少量的D-Fuc,L-Ara和D-Xyl,其主链由β(或α)-D-1,4-Man,β-D-1,6-Glc和β-D-1,4-Gal组成,而阿拉伯糖通过α-L-T-Araf和α-L-1,5-Araf连接形成阿拉伯聚糖支链或与β-D-1,4-Galp的O3位相连形成阿拉伯半乳聚糖支链.
基金Natural Science Foundation of Shanghai,China(No.13ZR1453200)Specialized Research Fund for the Doctoral Program of Higher Education of China(No.20130074120017)
