Terminal double bonds in the alkenes and acetates of defensive secretion from the thrips Suocerathrips linguis Mound & Marullo, 1994 (Thysanoptera: Phlaeothripidae)

Defensive secretions of adult males and females of the subsocial thrips Suocerathrips linguis were examined using gas chromatography–mass spectrometry (GC–MS). The samples contained six long-chain acetates and five aliphatic alkanes and alkenes. Whole-body extracts yielded six methyl esters of fatty acids as well as hexadecyl acetate. Structures of the two main components, (11Z)-icosa-11,19-dienyl acetate and octadecyl acetate, were confirmed. The third most abundant substance was identified as octadec-17-enyl acetate, which is a new natural product. In addition, (9Z)-octadec-9-enyl acetate was identified along with other acetates. Pure icosadienyl acetate was found to remain liquid down to −15°C, and is the solvent for the solid components of the secretion cocktail. A tentative biosynthetic pathway for all of the 12 acetates, alkanes and alkenes is discussed, considering especially the components with terminal double bonds that are uncommon in Thysanoptera and other insects.     

Predicting bioavailability of PAHs in field-contaminated soils by passive sampling with triolein embedded cellulose acetate membranes

Triolein embedded cellulose acetate membrane (TECAM) was used for passive sampling of the fraction of naphthalene, phenanthrene, pyrene and benzo[a]pyrene in 18 field-contaminated soils. The sampling process of PAHs by TECAM fitted well with a first-order kinetics model and PAHs reached 95% of equilibrium in TECAM within 20 h. Concentrations of PAHs in TECAM (C_TECAM) correlated well with the concentrations in soils (r² = 0.693-0.962, p < 0.001). Furthermore, concentrations of PAHs determined in the soil solution were very close to the values estimated by C_TECAM and the partition coefficient between TECAM and water (K_TECAM-w). After lipid normalization nearly 1:1 relationships were observed between PAH concentrations in TECAMs and earthworms exposed to the soils (r² = 0.591-0.824, n = 18, p < 0.01). These results suggest that TECAM can be a useful tool to predict bioavailability of PAHs in field-contaminated soils.     

Linking Cellulose Fiber Sediment Methyl Mercury Levels to Organic Matter Decay and Major Element Composition

Methylation of mercury (Hg) to highly toxic methyl Hg (MeHg), a process known to occur when organic matter (OM) decomposition leads to anoxia, is considered a worldwide threat to aquatic ecosystems and human health. We measured temporal and spatial variations in sediment MeHg, total Hg (THg), and major elements in a freshwater lagoon in Sweden polluted with Hg-laden cellulose fibers. Fiber decomposition, confined to a narrow surface layer, resulted in loss of carbon (C), uptake of nitrogen (N), phosphorus (P), and sulfur (S), and increased MeHg levels. Notably, fiber decomposition and subsequent erosion of fiber residues will cause buried contaminants to gradually come closer to the sediment–water interface. At an adjacent site where decomposed fiber accumulated, there was a gain in C and a loss of S when MeHg increased. As evidenced by correlation patterns and vertical chemical profiles, reduced S may have fueled C-fixation and Hg methylation at this site.     

茅草添加与温度变化对餐厨垃圾厌氧水解产酸的影响简

比较了茅草添加在温度变化条件下对餐厨垃圾厌氧水解过程小分子有机酸产量的影响,提出一种新型餐厨垃圾的资源化方式。研究结果显示,餐厨垃圾在55℃条件下厌氧水解主要产物为乳酸,达到25.7 g/L,其干物质转化率可以达到32.1% （g TS）,而餐厨+茅草处理在同样条件下的乳酸产量为20.1 g/L,干物质转化率为25.1%。温度下降为37℃后继续进行的的厌氧水解,得到的主要产物是乙酸、丙酸和丁酸,餐厨处理和餐厨+茅草处理这两者的峰值分别为6.5、2.8、8.0和6.1 g/L、2.7 g/L和5.9 g/L。结果显示茅草添加可以在一定程度上调节水解产物的比例,而温度变化可以调控小分子有机酸的产量。本研究结果表明,厌氧水解是一种有潜力的小分子有机酸生产与餐厨垃圾资源化处理途径。     

含硫芳香族化合物降解酶的定域及胞内产物的鉴定

为研究含硫芳香族化合物的生物降解途径 ,采用静息细胞技术提取假单胞杆菌 (Pseudomonas sp.)不同部位的酶 .结果表明 ,对硝基苯砜基乙酸异丁酯降解酶主要定域在细胞膜周及膜内 .被试化合物在膜内酶的作用下 ,发生碳硫键断裂 ,降解产物是对硝基苯磺酸 .在膜周酶的作用下 ,发生碳硫键和酯的烷氧键 2种方式的断裂 ,生成对硝基苯磺酸和对硝基苯砜基乙酸 .     

醋酸纤维素包埋非水溶性介体催化强化生物反硝化特性

利用醋酸纤维素包埋法固定非水溶性醌类介体,研究其催化强化Paracoccus versutus菌株GW1的反硝化作用。结果表明,醌浓度在26.7 mmol/L时,固定化蒽醌(AQ)、1-氯蒽醌(1-AQ)、2-氯蒽醌(2-AQ)、1,5-二氯蒽醌(1,5-AQ)、1,8-二氯蒽醌(1,8-AQ)和1,4,5,8-四氯蒽醌(1,4,5,8-AQ)催化反硝化效率依次为:1,5-AQ1,8-AQ1,4,5,8-AQAQ1-AQ空白对照2-AQ。反应10 h时,1,5-AQ可使硝酸盐去除率比空白对照提高1.84倍;硝酸盐氮反硝化动力学拟合为零级反应,其速率常数Kx随1,5-AQ浓度的增加均呈线性增加(Kx=0.1885C1,5-AQ+8.378);水中溶解氧会降低GW1菌反硝化的效果;投加1,5-AQ的反硝化体系中亚硝酸盐积累的最大值比不投加介体的低48.3%;醋酸纤维素介体小球经过4次的重复利用,催化效果始终是空白对照的1.5倍以上。醋酸纤维素固定化非水溶性醌可以有效加速生物反硝化,表明其是一种较优的醌固定化方法,具有良好的应用价值。     

苯砜基化合物溶解度和分配系数的测定与估算

本文应用线溶剂化能相关法研究了３２种类砜基化合物的溶解度及分配系数与溶剂化显色参数之间的相关性，结果表明，溶解度和分配系数与溶剂化显色参数呈良好的线性关系，测定值与估算值吻合得很好。     

The effect of clay catalyst on the chemical composition of bio-oil obtained by co-pyrolysis of cellulose and polyethylene

Cellulose/polyethylene (CPE) mixture 3:1, w/w with and without three clay catalysts (K10 – montmorillonite K10, KSF – montmorillonite KSF, B – Bentonite) addition were subjected to pyrolysis at temperatures 400, 450 and 500 °C with heating rate of 100 °C/s to produce bio-oil with high yield. The pyrolytic oil yield was in the range of 41.3–79.5 wt% depending on the temperature, the type and the amount of catalyst. The non-catalytic fast pyrolysis at 500 °C gives the highest yield of bio-oil (79.5 wt%). The higher temperature of catalytic pyrolysis of cellulose/polyethylene mixture the higher yield of bio-oil is. Contrarily, increasing amount of montmorillonite results in significant, almost linear decrease in bio-oil yield followed by a significant increase of gas yield. The addition of clay catalysts to CPE mixture has a various influence on the distribution of bio-oil components. The addition of montmorillonite K10 to cellulose/polyethylene mixture promotes the deepest conversion of polyethylene and cellulose. Additionally, more saturated than unsaturated hydrocarbons are present in resultant bio-oils. The proportion of liquid hydrocarbons is the highest when a montmorillonite K10 is acting as a catalyst.     

Bioinspired cellulose-based membranes in oily wastewater treatment

• Cellulose-based membrane separates oily wastewater mimicking the living things. • The three central surface mechanisms were reviewed. • Preparation, performance, and mechanism are critically evaluated. • First review of wettability based cellulose membrane as major material. • The current and future importance of the research are discussed. It is challenging to purify oily wastewater, which affects water-energy-food production. One promising method is membrane-based separation. This paper reviews the current research trend of applying cellulose as a membrane material that mimics one of three typical biostructures: superhydrophobic, underwater superoleophobic, and Janus surfaces. Nature has provided efficient and effective structures through the evolutionary process. This has inspired many researchers to create technologies that mimic nature’s structures or the fabrication process. Lotus leaves, fish scales, and Namib beetles are three representative structures with distinct functional and surface properties: superhydrophobic, underwater superoleophobic, and Janus surfaces. The characteristics of these structures have been widely studied and applied to membrane materials to improve their performance. One attractive membrane material is cellulose, which has been studied from the perspective of its biodegradability and sustainability. In this review, the principles, mechanisms, fabrication processes, and membrane performances are summarized and compared. The theory of wettability is also described to build a comprehensive understanding of the concept. Finally, future outlook is discussed to challenge the gap between laboratory and industrial applications.     

Cellulose Fiber/Bentonite Clay/Biodegradable Thermoplastic Composites

Adding cellulose fiber reinforcement can improve mechanical properties of biodegradable plastics, but fiber must be well dispersed to achieve any benefit. The approach to dispersing fiber in this study was to use aqueous gels of sodium bentonite clay. These clay-fiber gels were combined with powdered compostable thermoplastics and calcium carbonate filler. The composite was dried, twin-screw extruded, and injection molded to make thin parts for tensile testing. An experimental design was used to determine the effect of fiber concentration, fiber length, and clay concentration. Polybutylene adipate/terephthalate copolymer (PBAT) and 70/30 polylactic acid (PLA)/PBAT blend were the biodegradable plastics studied. The composite strength decreased compared to the thermoplastics (13 vs. 19 MPa for PBAT, 27 vs. 38 MPa for the PLA/PBAT blend). The composite elongation to break decreased compared to the thermoplastics (170% vs. 831% for PBAT, 4.9% vs. 8.7% for the PLA/PBAT blend). The modulus increased for the composites compared to the thermoplastic standards (149 vs. 61 MPa for PBAT, 1328 vs. 965 MPa for the PLA/PBAT blend). All composite samples had good water resistance.