• Energy Research

AbstractBiodiesel is a low‐carbon‐intensity renewable fuel with up to 99% lower greenhouse gas emissions than petroleum‐based diesel. The use of oil crops for biodiesel is under critical examination. It is expensive and suffers from the food versus fuel risk/benefit problem. Consequently, many countries (e.g. Malaysia and countries in the EU) are scaling back the use of oil crops as feedstock for biofuel production. The limitations of these traditional crops are leading the renewable fuels industry to consider innovative, sustainable, and profitable biomass‐based platforms. Plant genetic engineering and other new breeding technologies are essential for developing such biomass‐based platforms because they enhance plant tolerance to abiotic and biotic stresses, resulting in higher feedstock yields, greater net energy gain, and the generation of high‐value co‐products. We review and summarize the recent improvements of oil crops through plant genetic engineering that may increase widespread and cost‐effective production of biodiesel and value‐added co‐products for green chemistry applications. © 2017 Society of Chemical Industry and John Wiley & Sons, Ltd

The extraction and transesterification of soil lipids into fatty acid methyl esters (FAMEs) is a useful technique for studying soil microbial communities. The objective of this study was to find the best solvent mixture to extract soil lipids with a pressurized solvent extractor system. Four solvent mixtures were selected for testing: chloroform:methanol:phosphate buffer (1:2:0.8, v/v/v), chloroform:methanol (1:2, v/v), hexane:2-propanol (3:2, v/v) and acetone. Soils were from agricultural fields and had a wide range of clay, organic matter and microbial biomass contents. Total lipid fatty acid methyl esters (TL-FAMEs) were the extractable soil lipids identified and quantified with gas chromatography and flame ionization detection. Concentrations of TL-FAMEs ranged from 57.3 to 542.2 nmole g(-1) soil (dry weight basis). The highest concentrations of TL-FAMEs were extracted with chloroform:methanol:buffer or chloroform:methanol mixtures than with the hexane:2-propanol or acetone solvents. The concentrations of TL-FAMEs in chemical groups, including saturated, branched, mono- and poly-unsaturated and hydroxy fatty acids were assessed, and biological groups (soil bacteria, mycorrhizal fungi, saprophytic fungi and higher plants) was distinguished. The extraction efficiency for the chemical and biological groups followed the general trend of: chloroform:methanol:buffer> or =chloroform:methanol>hexane:2-propanol=acetone. Discriminant analysis revealed differences in TL-FAME profiles based on the solvent mixture and the soil type. Although solvent mixtures containing chloroform and methanol were the most efficient for extracting lipids from the agricultural soils in this study, soil properties and the lipid groups to be studied should be considered when selecting a solvent mixture. According to our knowledge, this is the first report of soil lipid extraction with hexane:2-propanol or acetone in a pressurized solvent extraction system.

Earthworm distribution in global soils Earthworms are key components of soil ecological communities, performing vital functions in decomposition and nutrient cycling through ecosystems. Using data from more than 7000 sites, Phillips et al. developed global maps of the distribution of earthworm diversity, abundance, and biomass (see the Perspective by Fierer). The patterns differ from those typically found in aboveground taxa; there are peaks of diversity and abundance in the mid-latitude regions and peaks of biomass in the tropics. Climate variables strongly influence these patterns, and changes are likely to have cascading effects on other soil organisms and wider ecosystem functions. Science , this issue p. 480 ; see also p. 425

AbstractThere is an urgent need to develop viable, renewable, sustainable energy systems that can reduce global dependence on fossil fuel sources of energy. Biofuels such as ethanol are being utilized as blends in surface transportation fuels and have the potential to improve sustainability and reduce greenhouse gas emissions in the short term. Bioethanol, the most widely used liquid biofuel, is currently produced by converting sugars or starches from feed crops into ethanol. Use of this fuel source displaces and draws water consumption away from agricultural crops, increases soil erosion by shifting land from perennial grasses to annual crops, and increases use of fertilizers and insecticides. In contrast, bioethanol made from lignocellulosic biomass feedstocks does not have these limitations and in addition, offers a larger resource base: the amount of cellulosic material available for potential use vastly outweighs the amount of available starch‐based feedstock. Therefore, bioethanol from lignocellulosic biomass has attracted considerable interest from biofuel developers. This review is an update of some developments to optimize cellulose extraction from feedstock crops and to improve crop yields and logistics. It concludes that agricultural and forestry systems that incorporate lignocellulosic biomass crops can be designed for improved ecological function and energy use efficiency. Development of crops that have both desirable cell‐wall traits and high biomass productivity under sustainable low‐input conditions can significantly enhance the economics and efficiency of the conversion process. Optimizing the logistics of moving feedstock from field or forest to bio‐refinery can significantly reduce costs of using lignocellulosic feedstocks. © 2013 Society of Chemical Industry and John Wiley & Sons, Ltd