碱法麦草浆木聚糖酶处理后木质素及碳水化合物的变化

采用UV光谱、凝胶色谱、X—射线衍射及扫描电镜等技术对碱法麦草浆的酶解浆和酶解液进行分析,探讨了木聚糖酶对碱法麦草浆处理后浆中木质素和碳水化合物的变化情况。研究认为,木聚糖酶对碱法麦草浆漂白作用主要是因为木聚糖酶降解了浆中部分木聚糖和残余木质素中的LCC结构,从而使后序漂白中漂液更易渗透,木质素的溶出更多、更易。     

高粱秆制取草酸新工艺研究

研究了以高粱秆为原料用水解-氧化-水解法制取草酸的工艺方法.最佳反应条件是:质量分数为70%的硫酸,物料浸泡时间3 h,m(硝酸):m(高梁秆):m(催化剂)为2.1:1:0.002,氧化水解反应时间5 h,反应温度65℃.此条件下,草酸二水合物收率可达76.0%.     

微波在植物纤维漂白中的应用研究

采用微波辐射技术，建立了次氯酸钠漂白麦草浆工艺。影响微波辐射漂白纸浆的因素有三项：微波辐射时间、辐射功率和次氯酸钠用量。当微波辐射功率为352w，辐射时间为2min，次氯酸钠用量为10mL时，2g绝干浆的白度达77％ISO以上。此外，通过与水浴的对比实验，发现微波加热2min纸浆达到的白度相当于水浴加热40min，这对于能源的节省是非常有意义的。     

麦草浆黑液降粘消除硅干扰的研究

针对麦草浆黑液蒸发难的问题，采用补加烧碱消除硅干扰从而降低粘度的方法改善其蒸发性能。实验结果表明：补加烧碱能降低黑液粘度60％左右，基本上消除了硅干扰。     

酶水解小麦秸秆纤维素研究

对小麦秸秆纤维素的生物降解进行了探索。考察了酶的用量、底物浓度、pH值及其在线控制、反应时间诸因素对酶解反应的影响。实验结果表明最适宜反应条件为:酶/小麦秸秆=0 04、秸秆浓度为5%、反应时间3天、在线控制pH值4 8,在此条件下,酶解率可达60 4%。     

一株里氏木霉产纤维素酶的条件及酶系的优化

对一株里氏木霉突变株液体发酵产纤维素酶的培养条件进行了优化,确定培养基的最适碳源和氮源种类及添加量(g/L)分别为:小麦秸秆15,小麦麸皮5,尿素10～15,(NH4)2SO412,NH4NO35;最适培养条件为:接种种龄72h,接种孢子悬液浓度2×107个/mL,培养温度30～32℃,pH值5 0,培养时间144h,摇瓶转速180r/min,装液量75mL/250mL三角瓶.在培养里氏木霉的培养基中同时接种黑曲霉(二者孢子数比为60∶1)进行混合培养,β 葡萄糖苷酶的产量是对照试验的2 9倍,明显改善了纤维素酶系的比例,提高了它们之间的协同作用效果,在最适培养条件下,粗酶液的β 葡萄糖苷糖活和FPA酶活分别达到127 6U/mL和84 8U/mL.     

纺织机械并条机数显与控制装置

本文给出了纺织机械并条机数显与控制装置的硬件原理图和工作过程软件框图，介绍了装置的功能、特点及抗干扰措施。该装置的功能齐全、可靠性高、使用方便、性能优良，是纺织机械实现机电一体化过程中值得推广的一种电子产品。     

Efficiency of acetic acid and formic acid as a catalyst in catalytical and mechanocatalytical pretreatment of barley straw

In this study, the potential of organic acids (formic acid, acetic acid) in a catalytical and mechanocatalytic conversion of lignocellulosic barley straw to valuable sugars is explored using sulfuric acid as a reference. Acid-catalyzed hydrolysis has been carried out with acid-impregnated samples as well as unmodified barley straw. In the mechanocatalytical approach, pretreatment consists of impregnation with the acid catalyst and mechanical treatment by ball milling following chemical hydrolysis. Straw samples and residues were analyzed by Fourier transform infrared spectrometry (FT-IR) whereas hydrolysate analysis was based on total reducing sugar (TRS) determination following the DNS method and capillary electrophoresis (CE) analysis. The results indicated that acetic acid and formic acid are rather mild acids yielding low TRS levels compared to the reference acid. Mechanocatalytical pretreatment slightly increased TRS yields, but not significantly. Strikingly, sulfuric acid showed an efficient conversion efficiency yielding almost 45% of TRS. Furthermore, this study provided evidence for the acetylation of straw components when acetic acid was used as catalyst. Alkali hydrolysis induced the de-esterification, but revealed no significant increase of TRS yields.     

Assessment of the structural factors controlling the enzymatic saccharification of rice straw cellulose

In this study, the structural factors controlling the enzymatic saccharification of rice straw cellulose were examined by preparing structure-modified rice straw samples such as dewaxed, alkali-treated, oxidized, and swollen rice straw. It was found that the initial enzymatic saccharification rate of the various structure-modified samples was largely controlled by the initial cellulose surface area of the cellulose unit. Although the presence of lignin limited the cellulose surface area, there was no strong relationship between the lignin content and the initial reaction. On the other hand, the long-term enzymatic saccharification of rice straw cellulose highly depended on the lignin removal rate (lignin content). It was also found that silica is not a crucial factor in controlling the enzymatic saccharification.     

Mesophilic biohydrogen production from calcium hydroxide treated wheat straw

The use of Ca(OH)₂ pre-treatment to improve fermentative biohydrogen yields, from wheat straw was investigated. Wheat straw was pre-treated with 7.4% (w/w) Ca(OH)₂ at ambient temperature (20 °C) for 2, 5, 8, and 12 days, prior to 35 °C fermentation with sewage sludge inoculum. Biohydrogen yields were evaluated during dark fermentation and simultaneous saccharification fermentation (SSF) of total pre-treated straw material and compared to those from separated solid and hydrolysate fractions. Ca(OH)₂ pre-treatment followed by SSF, exhibited a synergetic relationship. On average, 58.78 mL-H₂ g-VS⁻¹ was produced from SSF of pre-treated and filtered solids. This was accompanied by approximately a 10-fold increase in volatile fatty acid production, compared to the untreated control. By omitting pre-treatment hydrolysate liquors from SSF, H₂ production increased on average by 35.8%, per VS of harvested straw. Additional inhibition studies indicated that CaCO₃, formed as a result of pre-treatment pH control, could promote homoacetogenesis and reduce biohydrogen yields.