固定化漆酶对刚果红染料脱色降解的研究

[目的]探讨固定化漆酶脱色降解刚果红染料的最佳反应条件。[方法]以海藻酸钠为载体、戊二醛为交联剂,进行漆酶的固定化,并研究了固定化漆酶用量、染料浓度、反应温度和pH对染料脱色率的影响。[结果]固定化漆酶脱色降解刚果红染料的最佳条件为酶用量1 g,染料浓度40 mg/L,反应温度65℃,pH=4.5。在该条件下降解3 h,固定化漆酶对刚果红染料的脱色率达92.6%,重复利用5次后,脱色率仍能保持在50%左右。[结论]该研究为染料废水的有效处理提供了理论依据。     

雷公藤细胞的固定化研究

利用海藻酸钠凝胶包埋法构建了雷公藤细胞固定化培养体系,研究了固定化细胞的生长及雷公藤甲素合成的变化情况。结果表明,固定化细胞经历了缓慢、指数及稳定3个生长阶段;固定化细胞培养液总糖、可溶性蛋白及丙二醛的含量随着培养时间增加而逐渐减少;pH值则呈现先上升后下降的变化趋势;而细胞活力却呈现先下降后上升的趋势;培养过程中过氧化物酶活性的变化呈现"V"字型;超氧化物歧化酶活性变化不大;苯丙氨酸解氨酶活性先上升而后缓慢下降;雷公藤甲素的合成具有较好的同增效应,细胞内外的甲素含量都在培养的第15天达到了最大值。     

Chemical structures and bioactivities of sulfated polysaccharides from marine algae

Sulfated polysaccharides and their lower molecular weight oligosaccharide derivatives from marine macroalgae have been shown to possess a variety of biological activities. The present paper will review the recent progress in research on the structural chemistry and the bioactivities of these marine algal biomaterials. In particular, it will provide an update on the structural chemistry of the major sulfated polysaccharides synthesized by seaweeds including the galactans (e.g., agarans and carrageenans), ulvans, and fucans. It will then review the recent findings on the anticoagulant/antithrombotic, antiviral, immuno-inflammatory, antilipidemic and antioxidant activities of sulfated polysaccharides and their potential for therapeutic application.     

Expression and Characterization of a Cold-Adapted Alginate Lyase with Exo/Endo-Type Activity from a Novel Marine Bacterium Alteromonas portus HB161718T

The alginate lyases have unique advantages in the preparation of alginate oligosaccharides and processing of brown algae. Herein, a gene alg2951 encoding a PL7 family alginate lyase with exo/endo-type activity was cloned from a novel marine bacterium Alteromonas portus {"type":"entrez-nucleotide","attrs":{"text":"HB161718","term_id":"239323637"}}HB161718^T and then expressed in Escherichia coli. The recombinant Alg2951 in the culture supernatant reached the activity of 63.6 U/mL, with a molecular weight of approximate 60 kDa. Alg2951 exhibited the maximum activity at 25 °C and pH 8.0, was relatively stable at temperatures lower than 30 °C, and showed a special preference to poly-guluronic acid (polyG) as well. Both NaCl and KCl had the most promotion effect on the enzyme activity of Alg2951 at 0.2 M, increasing by 21.6 and 19.1 times, respectively. The TCL (Thin Layer Chromatography) and ESI-MS (Electrospray Ionization Mass Spectrometry) analyses suggested that Alg2951 could catalyze the hydrolysis of sodium alginate to produce monosaccharides and trisaccharides. Furthermore, the enzymatic hydrolysates displayed good antioxidant activity by assays of the scavenging abilities towards radicals (hydroxyl and ABTS+) and the reducing power. Due to its cold-adapted and dual exo/endo-type properties, Alg2951 can be a potential enzymatic tool for industrial production.     

Digital ink-jet printing for chitosan-treated cotton fabric

In this paper, chitosan was suggested for using as a replacement for sodium alginate in the pretreatment print paste for digital ink-jet printing for cotton fabric. Pretreatment print pastes prepared from the mixture of chitosan and acetic acid with the appropriate viscosity gave satisfactory prints on the cotton fabric. Chitosan-treated cotton fabrics were digitally irk-jet printed with four different colors and the color fastness rating of the printed fabrics was satisfactory. Experimental results revealed the possibility of pre-treating the cotton with chitosan to replace the sodium alginate normally present in the pretreatment print paste recipe.     

饲料添加半乳甘露寡糖对刺参幼参生长、体壁营养组成及免疫力的影响

以初始体质量为(1.79±0.06) g的刺参(Apostichopus japonicus)为研究对象, 进行为期8周养殖实验, 研究饲料中添加半乳甘露寡糖对刺参生长、消化、体壁营养组成及免疫力的影响。以基础饲料(E0)为对照组, 在基础饲料中分别添加0.2% (E1)、0.4% (E2)、0.8% (E3)、1.2% (E4)和1.6% (E5)的半乳甘露寡糖, 共配制5种实验饲料。结果表明: (1) 饲料中添加不同浓度的半乳甘露寡糖对幼参增重率及特定生长率具有显著影响, 各处理组均显著高于对照组(P<0.05), 而对脏壁比及肠壁比无显著影响(P>0.05), 1.2%(E4组)添加水平下, 刺参增重率及特定生长率最高。(2) 饲料中添加不同浓度的半乳甘露寡糖对幼参肠道蛋白酶、淀粉酶、纤维素酶活力均无显著影响(P>0.05)。(3) 饲料中添加不同浓度的半乳甘露寡糖对幼参体壁酸性黏多糖及糖醛酸含量无显著影响(P>0.05)。添加半乳甘露寡糖比例0.2%(E1)、0.4%(E2)、0.8%(E3)、1.2%(E4)的处理组, 刺参体壁氨基酸总量及谷氨酸、甘氨酸、精氨酸含量显著高于对照组(P<0.05), 而1.6%(E5)组体壁氨基酸总量及Glu、Gly、Arg含量与对照组无显著差异(P>0.05)。(4) 饲料中添加半乳甘露寡糖对体壁及体腔液超氧化物歧化酶、碱性磷酸酶及溶菌酶活性具有显著影响(P<0.05), 同时对体腔细胞溶菌酶活性影响显著(P<0.05)。实验可以得到以下结论: (1) 饲料中添加半乳甘露寡糖不仅可以提高刺参免疫力, 并且可以提高特定生长率, 并改善体壁氨基酸组成; (2) 刺参饲料中半乳甘露寡糖的合适添加比例为1.2%。     

微粒化固体鱼油加工新工艺——喷雾定型固化法

本文介绍了微粒化固体鱼油加工新工艺——喷雾定型固化法的主要操作要点和注意事项,该工艺以食用褐藻酸钠作为鱼油的壁囊材料,用氯化钙溶液作为定型液,将均质的鱼油褐藻酸钠混合液用喷雾法喷入氯化钙溶液中定型,经水洗、烘干后得到微粒化固体鱼油。     

Alginate coarse/nanoemulsions containing Zataria multiflora Boiss essential oil as edible coatings and the impact on microbial quality of trout fillet

In this study, the effect of edible coarse/nanoemulsions of alginate as coating containing Zataria multiflora Boiss essential oil (ZEO) on the microbial quality of fish fillets was investigated at three concentrations (i.e. 0.25%, 0.5% and 1% [w/v]) in 16 days of storage at 4°C. Moreover, a comparison was made between the fabricated coarse emulsion and nanoemulsion coatings by particle size and polydispersity index analyses. Sample analysis was performed with regard to total viable count (TVC), total psychrophilic count (TPC), hydrogen sulphide‐producing bacteria count (HSC) and Enterobacteriaceae count (ENC) on days 0, 4, 8, 12 and 16. According to the findings, all the samples showed increased microbial counts during the storage periods. The highest reduction rates of TVC (about 2 log CFU/g), TPC (about 1 log CFU/g), HSC (about 1.5 log CFU/g) and ENC (about 3 log CFU/g) were observed in the nanoemulsion of alginate containing 1% w/v ZEO (NE 1%) samples, compared with alginate and control samples. The microbial growth was significantly inhibited in all treatments, compared with that in the control (p < .05). Accordingly, it can be concluded that nanoemulsion coating was more effective than coarse emulsion to prolong the durability of fish fillets and revealed a faster and greater inhibition of microbial flora, compared with coarse emulsions during the storage time.     

牛至精油-介孔纳米二氧化硅/海藻酸钠复合膜对双孢蘑菇保鲜效果研究

为了研究牛至精油-介孔纳米二氧化硅/海藻酸钠复合膜对双孢蘑菇保鲜效果的影响,本研究以海藻酸钠、介孔纳米二氧化硅(mesoporous silica nanoparticles,MSNPs)和牛至精油(oregano,OEO)为原料制备抑菌复合膜,对双孢蘑菇进行包装,以未添加OEO-MSNPs的纯海藻酸钠膜为对照组,未经...     

茶多酚-海藻酸钠涂膜处理对草鱼储藏品质的影响

对茶多酚-海藻酸钠复合涂膜提升储藏过程中草鱼品质的可行性进行了研究。在1.5%海藻酸钠溶液中分别加入0、1%、2%、3%(m/m)的茶多酚,制成茶多酚与海藻酸钠复合涂膜剂处理草鱼片,并以不作涂膜处理为对照组（CK）,考察草鱼储藏过程中鱼肉的持水性、pH、菌落总数、挥发性盐基氮（TVB-N）、硫代巴比妥酸值（TBARS）及质构特性的变化。结果表明：与对照组相比,茶多酚-海藻酸钠涂膜组草鱼品质变化程度明显较低,并且涂膜中茶多酚含量越高,鱼肉品质保持越好。由此说明,茶多酚-海藻酸钠涂膜能够有效控制鱼肉品质的劣变,保鲜效果良好,且以3.0%茶多酚+海藻酸钠涂膜组处理保鲜效果最佳,能够有效延长鱼肉的储藏期6 d左右。