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In light of climate change and the increasingly limited availability of energy resources, any form of renewable raw materials that can be used for energy production should be accounted for. One of the most promising renewable sources is considered to be that of lignocellulosic feedstock. In urban forestry and greening, millions of tons of lignocellulosic waste is produced every year but that biomass mostly goes unused. The aim of this research project was to investigate the utilisation potential of this very form of waste biomass using a medium-sized town as a sample for the work (Tartu in Estonia, with a population circa 100,000). Woody and non-woody vegetation representing greening waste from different seasons was investigated: spring and autumn leaves, and mixed waste from urban greening which contained grass, twigs, and leaves. BMP assays were conducted to estimate the biogas production potential and the three step bio-ethanol production process was used to estimate the bio-ethanol production potential. In the bio-ethanol production process, an N2 explosion pre-treatment was used, followed by enzymatic hydrolysis and fermentation. Map analysis was used to assess the area that was manageable by urban forestry and greening in the city of Tartu in order to estimate the amount of greening and forestry waste that was available for bioconversion and the volumes of biofuel that could be produced. 相似文献
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通过对虉草的热值和灰分进行测定,探讨虉草热值和灰分的动态变化及二者之间相关性.结果表明,虉草干重热值呈现双峰的变化趋势,峰值分别出现在孕穗期和成熟期;虉草灰分含量随物候期呈现先降低后升高的变化趋势,成熟期灰分含量最低;去灰分热值随着生育时期推迟呈现逐渐降低的变化趋势,其顺序为孕穗期＞抽穗期＞盛花期＞成熟期＞果后营养期＞枯黄期;各生育期干重热值与灰分含量之间均表现为负相关关系,其中抽穗期表现为极显著线性负相关(P＜0.01),孕穗期和果后营养期表现为显著线性负相关(P＜0.05),盛花期、成熟期和枯黄期相关性不显著. 相似文献
3.
Short-term responses of soil decomposer and plant communities to stump harvesting in boreal forests 总被引：2，自引：0，他引：2
Recently, in addition to logging residues, stumps have become an important component in energy production since there is growing global interest in the use of renewable energy sources in order to decrease anthropogenic carbon emissions. Harvesting of stumps influences the forest floor by changing vegetation and soil organic layers and exposing mineral soil across large areas. We studied whether stump harvesting after clear felling poses further short-term changes in boreal forest soil decomposer community (microbes and mesofauna) and vegetation when compared to the traditional site preparation practice (mounding). In general, stump harvesting caused decline in enchytraeid abundance but did not induce further major changes in decomposer community otherwise nor in vegetation of each soil micro-habitat (intact soil and exposed mineral soil). However, the abundances of almost all decomposer animals were lower in the exposed mineral soil than in the intact soil. Stump removal increased the area of exposed mineral soil in the clear felled areas, leading to lower amount of high quality habitat for most decomposer organisms. Hence, it is obvious that there are (or will be) differences in the decomposer community dynamics between the treatments at the forest stand level. Both species richness and coverage of plants benefitted from large-scale exposure of mineral soil. Because the stump removal procedure disturbs soil organic layers and negatively affects the decomposer community, it has the potential to alter nutrient dynamics in forests. 相似文献
4.
The rise in global population has led to explorations of alternative sources of energy and food. Because corn and soybean are staple food crops for humans, their common use as the main source of dietary energy and protein for food-producing animals directly competes with their allocation for human consumption. Alternatively, de-fatted marine microalgal biomass generated from the potential biofuel production may be a viable replacement of corn and soybean meal due to their high levels of protein, relatively well-balanced amino acid profiles, and rich contents of minerals and vitamins, along with unique bioactive compounds. Although the full-fatted (intact) microalgae represent the main source of omega-3 (n-3) polyunsaturated fatty acids including docohexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the de-fatted microalgal biomass may still contain good amounts of these components for enriching DHA/EPA in eggs, meats, and milk. This review is written to highlight the necessity and potential of using the de-fatted microalgal biomass as a new generation of animal feed in helping address the global energy, food, and environmental issues. Nutritional feasibility and limitation of the biomass as the new feed ingredient for simple-stomached species are elaborated. Potential applications of the biomass for generating value-added animal products are also explored. 相似文献
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Sweet sorghum (Sorghum bicolor (L.) Moench) is particularly suitable as a feedstock for a variety of bioprocesses, largely because of its high yields of both lignocellulosic biomass and fermentable saccharides. Sweet sorghum is less economically important for refined sugar production than other sugar crops, e.g., sugar beet and sugarcane, but can produce more raw fermentable sugar under marginal conditions than those crops. In this review, the agronomic requirements of sorghum (viz., water, soil, and nutrient requirements), cultural practices, and plant morphology are discussed from a bioprocessing perspective. Historically, sugar extraction from the plant in the form of juice has been of primary interest; these methods, along with modern developments are presented. Recently, the direct yeast fermentation of sorghum juice for ethanol production has been studied. Additionally, the bagasse resulting from the juice extraction has been used for a variety of potential products: forage, silage, combustion energy, synthesis gas, and paper. The bagasse contains high levels of relatively low crystallinity cellulose, along with relatively labile lignin, and so is itself of interest as a fermentation feedstock. Whole sorghum stalk, and its bagasse, have been subjected to studies of a wide array of pretreatment, enzymatic hydrolysis, and fermentation processes. The potential fermentation products of sweet sorghum are wide ranging; those demonstrated include ethanol, acetone, butanol, various lipids, lactic acid, hydrogen, and methane. Several potential native products of the plant, in addition to cellulose for paper production, are also identified: waxes, proteins, and allelopathic compounds, such as sorgoleone. 相似文献
7.
Robert V. ParsonsKari A.L. Parsons John L. Sorensen 《Industrial Crops and Products》2011,34(1):1245-1249
This work investigated the yield and nature of solvent-soluble organic compounds extracted from flax shive using a room temperature reaction (20 °C) with sodium ethoxide catalyst at four different concentrations (0.2, 0.5, 0.7, and 1.0 M) in anhydrous ethanol. Results were compared with the use of aqueous sodium hydroxide (1.0 M) at two different reaction temperatures (20 °C and 100 °C). Quantitative yield from flax shive varied linearly with sodium ethoxide concentration and averaged 54.5 mg/g on a dry-mass basis (db) at 1.0 M. In contrast, the quantitative yield using 1.0 M sodium hydroxide was much lower, averaging 2.2 mg/g (db). Yield did not differ significantly due to changes of particle size in either case, or due to changes of temperature over the range considered in the case of sodium hydroxide.Analyses using proton nuclear magnetic resonance (1H NMR) confirmed all extracts to contain aromatic compounds, thus likely lignin derived, but found differences in chemical characteristics between the two extraction methods. One key difference was the presence of compounds with methyl ether groups in sodium hydroxide extracts that were absent in the case of sodium ethoxide extracts. Given that flax contains a mixed guaiacyl-syringyl lignin, methyl ether groups would be expected to be present. Control reactions on three model compounds were carried out to confirm that transesterification occurred with sodium ethoxide. These control reactions also demonstrated that methyl ether groups would be expected to remain intact under the extraction conditions reported here. In light of the higher yield of solvent soluble compounds recovered by extraction with basic ethanol, flax shive may represent a source of value-added phenolic constituents. This processing method may also represent a useful pre-treatment prior to the production of biofuels by cellulose degrading organisms. 相似文献
8.
Jessica L. Sarauer 《Scandinavian Journal of Forest Research》2018,33(8):781-792
Conversion of agricultural fields to bioenergy crops can affect greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Soil GHG emissions were measured seasonally in poplar bioenergy and agricultural fields at three Northwestern US locations. A forest stand was also used at one location for comparison. A portable gas analyzer was used to measure CO2 efflux and CH4 and N2O fluxes were first measured with chambers and later with gradients. Agricultural soil had 17% larger CO2 efflux rates than poplar soil. Chamber fluxes showed no differences in CH4 uptake but did show higher N2O fluxes in poplar than agricultural soil. Gradient CH4 uptake rates were highest in agricultural soil in the summer but showed no N2O flux differences. Forest soils had smaller quarterly CO2 efflux rates than agricultural soils and greater CH4 uptake rates than poplar soils. The largest GHG contributor to soil GHG flux was CO2, with those being ～1000 times larger than CH4 flux rates and ～500 times larger than N2O flux rates based on CO2 equivalences. Converting conventional agricultural cropland to poplar bioenergy production does not have adverse effects on soil greenhouse gas flux and these results could be useful for modeling or life cycle analysis of land use conversion. 相似文献
9.
The increasing demand for biofuel may decrease the dead wood supply in managed forests, and hence the amount of substrate available for dead wood dependent species. Slash is already being harvested for biofuel purposes, and stumps are an even bigger potential source of wood fuel. Both substrates constitute a major component of dead wood in managed forests, but have been poorly studied in terms of lichen diversity. We compared lichen species diversity between the lateral surface of slash and the cut surface of stumps of Norway spruce in planted boreonemoral Swedish forests of four age classes; 4-5, 8-9, 12-13, and 16-18 years. We also estimated the amounts of the two substrates, and discriminated between slash with bark and decorticated slash. There were no differences in species number per surface area, but slash had more species when equal volumes were compared. We found compositional differences between slash and stumps throughout the decay process. The majority of species found on both substrates were more frequent on stumps, which also had a higher number of unique species and species in the literature indicated as nationally rare or uncommon. The volume per hectare of stumps was ten times greater than that of slash but conversely, the lateral surface area of slash was five times greater than the cut surface area of stumps. Few dead wood specialist lichen species were, however, strictly associated with slash, whereas stumps offer a more heterogeneous environment and may provide important habitats for rare lichens in the managed forest landscape. 相似文献
10.
《Scandinavian Journal of Forest Research》2012,27(8):734-745
Abstract Stump harvesting as a way to increase wood biomass production in order to meet the European Union targets for reduced CO2 emissions is starting up in Sweden. The knowledge about if and how Collembola species can use low stumps as a substrate is very limited. Stumps of three different ages (4, 14 and 75 years) were sampled to see if Collembola used the dead wood during the whole rotation period of a forest. Stumps of spruce, pine and birch were compared. Both the bark and the splint wood of the stumps were sampled. To determine whether the stump also influenced the nearby soil, the soil close to the stump were sampled as well as the soil further away. In total, five Collembola species that are known to prefer dead wood as a substrate were found in the stumps. Wood specialists were more dominating in young stumps, but occurred also in the oldest stumps. No preference was found for any specific tree species. Wood-living Collembola seem to be able to survive in low stumps for a whole rotation period, at least in low numbers. There is, however, a risk for extinction debt due to their low capacity for active long-distance dispersal. 相似文献