Effect of Additives on the Improvement of Mechanical and Degradable Properties of Photografted Jute Yarn with Acrylamide

The jute yarn was grafted with acrylamide monomer (AA) under ultraviolet (UV) radiation to modify its mechanical and degradable properties. A number of AA solutions of different concentrations in methanol (MeOH) along with photoinitiator Irgacure 907 [2-methyl-1-(4-methylthiophenyl)-2-morpholinopropanone-1] were prepared. The monomer concentration and irradiation time were optimized. Jute yarn grafted with 30% AA under UV radiation for 60 min showed of the highest polymer loading (PL) value of 22% with a enhanced tensile strength (TS) value of 195% and elongation at break (Eb) value of 256% compared to untreated jute yarn. To further improve the properties of jute yarn, a number of additives (1%) such as urea, polyvinylpyrrolidone, urethane acrylate, and urethane diacrylate were used in the AA (30%) solution. Among all the additives used, urea significantly influenced the PL (27%), TS (230%), and Eb (264%) values of the treated jute yarns. Water uptake and the degradation properties of treated and untreated jute yarn caused by simulated weathering and in soil (25% water) were also studied. The rate of degradation of grafted sample is lower then that of untreated sample. DSC studies showed the thermal stability of the AA plus urea grafted sample.     

High-Efficiency Production of Bioplastics from Biodegradable Organic Solids

Microbial polyhydroxyalkanoates (PHAs) have been extensively studied as environmentally friendly biodegradable thermoplastics. The major obstacle to wide acceptance of PHAs is their high price, mainly attributed to the costs of raw materials and polymer recovery. A large amount of organic solids are discarded from food production and consumption and may be used as carbonaceous raw materials for production of PHAs. A novel technology was investigated at bench-top scale to produce PHAs from food scraps. The harvested cell mass had a high PHA content (72.6% of dry cell mass), the same as obtained from pure glucose and organic acids. The organic solid was first digested in an acidogenic reactor in which about 60% solid was converted to fermentative products, including short-chain fatty acids. The four major acids were acetic, propionic, butyric, and lactic acids at concentrations of 6, 2, 27, and 33 g/L, respectively. The acids were transported through a membrane barrier via molecular diffusion to an airlift bioreactor, where the acids were utilized by an enriched culture of Ralstonia eutropha for PHA synthesis. Purification of fermentative acids was not performed in this molecular diffusion–based integration of acidogenesis and polymerization. By using a dialysis membrane as the barrier, the dry cell mass concentration and PHA content reached 22.7 g/L and 72.6%, respectively. The PHA was a copolymer of poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with 2.8 mole % of hydroxyvalerate.     

Functional Properties of Extruded Starch Acetate Blends

Starch acetate, with degree of substitution of 2, was blended with 0, 7.5 and 15% polylactic acid (PLA), Eastar Bio Copolyester 14766 (EBC) or Mater-Bi ZF03U (MBI) and 10%, 13%, or 16% (d.b.) ethanol and twin-screw extruded at 160°C barrel temperature. Physical characteristics of the extrudates, such as radial expansion ratio, unit and bulk densities, and of the mechanical properties, including unit spring index and bulk spring index, were measured. Type of polymer, polymer content, and ethanol content significantly affected the physical characteristics and mechanical properties. The sample extruded with 7.5% PLA and 13% ethanol had the highest expansion ratio and bulk spring index. The sample with 15% MBI and 16% ethanol had the lowest unit density, while the sample with 7.5% PLA and 16% ethanol had lowest bulk denisty. The highest unit spring index was expressed in the sample containing 7.5% PLA and 10% ethanol.     

Electrosynthesis of κ-Carrageenan Complexes with Gelatin

Electrosynthesis at pH 9, 12, and 11 of -carrageenan–gelatin complexes from electrolytes containing the components at proportions varying from 1:5 to 5:1 provided complexes in the composition varying in a range from 1:10 to 1:1.8. Components were bound mainly electrostatically, although partial insolubility of complexes in 7 M aqueous urea pointed to a part of the complexes bound covalently. None of the performed tests except solubility could confirm formation of covalent complexes. The complexation of -carrageenan to gelatin significantly increased the thermal stability of carrageenan, whereas the thermal stability of gelatin increased rather insignificantly.     

Effect of the composting substrate on biodegradation of solid materials under controlled composting conditions

Biodegradability under composting conditions is assessed by test methods, such as ASTM D 5338-92, based on the measurement of CO₂ released by test materials when mixed with mature compost and maintained in a controlled composting environment. However, in real composting, biodegradation occurs in fresh waste. To clarify this point, the biodegradation of paper and of a starch-based biodegradable thermoplastic material, Mater-Bi ZI01U, was followed by measuring the weight loss of samples introduced either into a mature compost or into a synthetic waste. The weight loss in mature compost was higher at the beginning but tended to decrease; in synthetic waste a first lag phase was followed by an exponential phase. Complete degradation of paper was noticed simultaneously in the two substrates (after 25 days). The bulkier Mater-Bi samples were fully degraded after 20 days in fresh waste, but after 45 days in mature compost. Therefore, the test methods using mature compost as a substrate can possibly underestimate the biodegradation rate occurring in fresh waste, i.e., in real composting plants, and have to be considered as conservative test methods. The test procedure described in this paper seems very suitable as a screening method to verify the compostability of plastic materials in a composting environment.     

Bark salicylates and condensed tannins reduce vole browsing amongst cultivated dark-leaved willows (<Emphasis Type="Italic">Salix myrsinifolia</Emphasis>)

Summary. Vole feeding amongst herbal willows that have a high concentration of salicylates in their bark and leaves, and may therefore be cultivated for use as raw material for herbal medicine was tested in the field and in laboratory conditions. Eight clones of dark-leaved willow (Salix myrsinifolia Salisb.) were cultivated for two years with six different methods combining three fertilisation levels (none, low and high), black plastic mulch applied for suppressing weed competition and unmulched control. Samples for the laboratory feeding trial were taken from the unfertilised plants during willow winter dormancy and twigs were fed to 16 voles as a multi-choice experiment. The bark area removed was calculated from image analysis of the material left by the voles. The diameter and the bark thickness of the twigs were measured. Concentrations of salicin, salicortin, HCH-salicortin, picein, triandrin, triandrin derivative, gallocatechin, (+)-catechin, luteolin-7-glucoside, hyperin, total condensed tannins and total nitrogen were measured from the twigs fed to voles in the laboratory. Browsing by a natural population of voles amongst winter-dormant willows was measured in the field. In the laboratory, voles browsed on 80% of the twigs and in the field voles browsed on 33% of the twigs. Vole feeding followed similar patterns in the field and in the laboratory experiment; feeding was clearly higher amongst the plants grown in unmulched control compared to those in plastic mulch. The same clones, 1, 2 and 6 were preferred in both experiments. Voles preferred thin twigs to thick ones. Feeding correlated negatively with concentrations of salicylates and tannins. As vole feeding seems to be highly affected by willow cultivation method and plant genotype, careful selection of cultivated clones and cultivation methods can enhance the reliability of herbal willow cultivation.     

Accumulation of poly(3-hydroxybutyric acid-co-3-hydroxyvaleric acid-co-4-hydroxyvaleric acid) by mutants and recombinant strains ofAlcaligenes eutrophus

Alcaligenes eutrophus accumulated a terpolyester of 3-hydroxybutyric acid (3HB), 3-hydroxyvaleric acid (3HV), and 4-hydroxyvaleric acid (4HV) during cultivation with 4HV as carbon and energy source under nitrogen starvation. The polyester accumulated by wild-type strains under these conditions contained 4HV at a molar fraction of approximately 5 mol% only. A catabolic pathway of 4HV was postulated, which included the activation of 4HV to 4HV-CoA and a conversion of 4HV-CoA to 3HV-CoA. Tn5::mob-induced mutants were isolated fromA. eutrophus HF39, which were affected in 4HV and/or valeric acid catabolism. Among 83 mutants were 27 4HV-negative or 4HV-leaky mutants; two mutants were identified which accumulated a terpolyester with a molar fraction of 10.1 to 22.7 mol% 4HV. In addition, a further increase in the molar fraction of 4HV in poly(3HB-co-3HV-co-4HV) and a two- to fourfold increase in the PHA synthase activity were monitored in these mutants or others and also in HF39, if the cells were complemented with the hybrid plasmid pHP1014::PP1, which contained the PHA biosynthesis genes ofA. eutrophus H16. Application of mutagenesis plus recombinant DNA techniques resulted in the accumulation of a terpolyester with up to 30 mol% 4HV and with approximately equimolar fractions of 3HB, 3HV, and 4HV.     

Jute bioblanket as a soil rehabilitation strategy in Sorocaba,Brazil: Soil chemistry and SWOT approaches

Soil erosion and the invasion of exotic plant species are major constraints to achieve sustainable development around the world. Currently, we find few products devoted concomitantly to combatting soil erosion as well as the establishment of unwanted exotic plants. In this paper, we introduce a new product, called herein a bioblanket, that protects the soil and impedes the establishment of exotic plant species. This product is of simple design, and to manufacture it, we use two biodegradable materials: jute tissue and grass wastes. We designed this product to combat soil erosion and the germination and establishment of new, unwanted, invasive plant species. In this paper, we describe our evaluation of how successful this product was in terms of improving the chemical attributes of soil. We also identified the product's potentialities and weaknesses by means of strengths, weaknesses, opportunities, and threats (SWOT) analysis. The bioblanket ameliorated the chemical attributes of the soil, as evidenced especially by the neutralization of acidity (8.5%) and aluminum toxicity (33%), and by an increment in nutrients concentration. We argue that after adequate treatment and management, the residues of plants that are normally considered unwanted materials can be transformed into a raw material to control the propagation of unwanted plant species, and concomitantly control soil erosion while improving the chemical conditions of the soil. The improvement of the soil chemical attributes was one of the main positive effects reported through the SWOT analysis. In addition, the SWOT analysis revealed some features that need improvement in future generations of the product, but we argue that these features do not impede the benefits for the use of the product in its present form.     

以聚羟基脂肪酸酯为固体碳源去除地下水中的硝酸盐

研究了可降解聚合物聚羟基脂肪酸酯（PHA）作为固体碳源和生物膜载体去除地下水中硝酸盐的影响因素。结果表明,低温反硝化有较大影响,5℃和10℃时的反硝化速率分别只有30℃时的5%和13%。反硝化对进水pH有较强的适应性,在pH4.5-9.5条件下,反硝化速率介于11.2-15.8mg/（Loh）之间。pH为4.5-8.5时,出水亚硝酸盐的浓度相差不大。DO对以反硝化速率影响不大,当进水DO为0.9mg/L-5.0mg/L时,反硝化速率介于12.6-15.8mg/（Loh）之间,出水NO2-N浓度的最大值为0.15 mg/L。     

Extraction of copper from sewage sludge using biodegradable chelant EDDS

[S,S]-Ethylenediaminedisuccinic acid(EDDS),a biodegradable chelant,was used to separate the heavy metals from the sewage sludge based on chemical extraction technology.Under various conditions,the extraction experiments were carried out for the sewage sludge from Shanghai Taopu Municipal Wastewater Plant,China.The influences ofpH and the concentration of EDDS on the extraction efficiency for copper(Cu)were discussed.The results showed that EDDS had higher extraction efficiency for Cu from the sewage slud...