Comparison of different procedures for the detoxification of eucalyptus hemicellulosic hydrolysate for use in fermentative processes

Eucalyptus (Eucalyptus grandis) shavings were submitted to an acid hydrolysis process with the aim of obtaining a hemicellulosic hydrolysate rich in fermentable sugars. However, the hydrolysate obtained contained, in addition to sugars, several compounds that are toxic to microorganisms, namely furfural, hydroxymethylfurfural, acetic acid and phenolics. In order to produce a hydrolysate suitable for use in fermentative processes, several procedures were evaluated for hydrolysate detoxification, including concentration by vacuum evaporation and adsorption on activated charcoal, diatomaceous earths, ion‐exchange resin or adsorbent resin. Hydrolysate concentration was especially effective for furfural removal, whereas the adsorbent resin was efficient in removing hydroxymethylfurfural, phenolics and acetic acid. Combination of this resin with activated charcoal was better than with diatomaceous earths for removal of acetic acid and phenolics. The best detoxification procedure evaluated was based on hydrolysate concentration followed by adsorption on activated charcoal and adsorbent resin. By this treatment, removal rates of 82.5, 100, 100 and 94% were attained for acetic acid, furfural, hydroxymethylfurfural and phenolics, respectively. Copyright © 2005 Society of Chemical Industry     

铬革屑脱铬提取胶原蛋白的研究进展

随着胶原蛋白应用领域的不断拓展,胶原蛋白的需求不断增长,尤其是高附加值的产品。综合论述国内外从铬革屑中提取胶原蛋白脱铬的研究方法,并对存在的一些问题提出改进措施,以期进一步高值转化皮革废料,为胶原蛋白的开发利用奠定理论基础。     

废铬革屑胶原蛋白与壳聚糖复合成膜的研究(续)

从废弃蓝皮屑中提取出胶原蛋白,对甲壳素脱乙酰制备壳聚糖,然后将两者与甘油共混制成复合膜,并对膜的机械性能、透水气率、吸水率进行了测定。试验研究了胶原蛋白分子质量、甘油用量、胶原蛋白与壳聚糖质量比、成膜溶液pH值及成膜温度对膜性能的影响。试验结果表明:甘油用量的质量浓度(相对于成膜溶液的总体积) 0 0 2 0kg/L ,胶原蛋白与壳聚糖质量比为0 1 6,成膜溶液pH值为3 81 ,成膜温度为5 0℃时,复合膜的抗拉强度和延伸率均为最大,分别为8 1 4MPa和5 1 6%。     

铬革屑的高值利用研究

采用分段从铬革屑中提取胶原蛋白的方法 ,制得铬含量和灰分含量分别低于 2mg/kg和 2 % ,平均分子量为 85kD的胶原蛋白。以此胶原蛋白为主要成分制备了胶原基创伤敷料 ,该敷料的物理机械性能、透气性以及与创伤的贴附性能良好 ,功能性评价结果表明 :该敷料与动物皮肤相容性好 ,无刺激反应 ,有明显的保护伤口、防止感染和促进伤口愈合的作用。这为含铬废弃物的高值利用 ,开辟了一个新的领域     

碱法水解脱铬革屑制备胶原蛋白水解物的研究

采用碱法水解脱铬革屑制备胶原水解产物 ,研究了影响胶原水解产物收获率的各种因素 ,得出的结论为 :碱法水解的最佳条件为CaO用量 4% (w/w)、反应时间lh、反应温度 60℃、水 -渣比 7,在此条件下 ,胶原水解产物的收获率为 5 5 .0 3 % ,分子量分布在 1 6.1 0kDal左右。本文还测定了胶原水解产物的理化性质     

铬革屑制备蛋白填充剂

对从铬革屑中提取胶原产物制备蛋白填充剂的方法进行了探讨。结果表明用碱处理铬革屑从中提取胶 原产物.用乙醇胺和己二酸对胶原产物进行酰胺化改性,可得到一种性能良好的蛋白填充剂。     

胶原基絮凝剂对中段废水的沉淀特性研究

采用以废皮屑为原料制备的胶原基絮凝剂(CF)处理造纸厂的中段废水,考察了在不同用量和不同pH值下对废水脱色率、CODCr去除率和TS去除率的影响,并对该废水的絮凝曲线进行了研究.结果表明,CF对中段废水具有显著的絮凝作用,它能有效地降低废水的色度和污染负荷.在CF(阳离子度1.55 mmol/g)用量为0.8 g/L,pH值为6 0的条件下,废水的脱色率、CODCr去除率和TS去除率分别为92.0％、47.8％和13.4％,且絮凝物沉降速度快,最终污泥体积小.     

Combined effect of sand grain size and contents of wood and filler on the physicomechanical properties and the microstructure of lightweight sand concrete

This paper attempts to model the main physicomechanical properties of a wood sand concrete using the ‘design of experiments’ method. The limestone filler content (F), the maximum diameter of sand grain (D), and the wood content (B) were taken as independent variables; while the dry density (d), the thermal conductivity (C), and the compressive strength (Rc) were taken as responses. For this study, experimental tests were performed and the above method was applied. The obtained results showed that the most significant variable that affects all the studied responses is ‘B.’ The effect of the other factors is relatively weaker with very clear domination of the factor ‘D’ compared to the factor ‘F’ which seems to be very negligible. Although it is also lower than those of ‘B’ and ‘D,’ the effect of the binary and ternary interactions (D×B, F×B, F×D and F×D×B) seems to be slightly higher than that of (F). In addition, the SEM analysis highlighted the more or less homogeneous aspect of the studied composite as well as the good adherence ‘wood-matrix’ and confirmed the dominant effect of the factor ‘B’ on the microstructure evolution of sand concrete. Moreover, according to ‘B’ it is possible to develop both structural concretes and structural-insulating concretes.     

蛋白鞣剂的研制与应用

本文对铬革屑水解后的残渣－－铬泥的利用进行了研究,采用碱水解和酶水解的方法将铬泥进一步水解提取胶原蛋白,用甲醛对胶原蛋白进行改性制备蛋白鞣剂回用于制革生产中,实验结果表明,用12％的甲醛（以胶原重计）改性得到的蛋白鞣剂用于猪皮鞣制,坯革收缩温度可达85℃,其填充性能好,且革坯色白,存放过程中基本不变色。     

Enhanced dark fermentative hydrogen production under the effect of zero-valent iron shavings

Dark fermentative hydrogen production under the effect of zero-valent metal shavings (iron, aluminum and copper) was studied by using a sucrose medium and a mixed bacterial consortium. The iron shavings were found to be unique to promote the hydrogen production, the hydrogen yield obtained from an optimal dose of 8–16 g/L reached 4.2 mol/mol hexose, doubled compared with that obtained from the control without addition of the iron shavings. The effect was more obvious in low pH buffered medium than in higher buffered medium. The aluminum and copper shavings were either inert or toxic to the cultivation. It is evident that the addition of the zero-valent iron helped maintaining the pH to an optimal range for hydrogen production and drove more reducing equivalents to the production of hydrogen. A microbial corrosion system mediated by the hydrogen producing bacteria was proposed to be responsible for the improvement of hydrogen production.