News and Trends

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A policy paper by Humberto S. Brandi, Romeu J.Daroda, and Taynah L. Souzastaff, of the National Institute of Metrology, Quality and Technology (Inmetro) (Brazil) describes the importance of standardization for transforming biofuels into an international commodity. The paper is published in the journal, Clean Technology and Environmental Policy (URL above). Recent reports indicate a global shifting scenario toward more investments in renewable energy, and this has been steadily growing at a steady pace. Many countries have instituted national policies to stimulate the production and use of biofuels (particularly bioethanol and biodiesel as transport biofuels). Some biofuel-producing countries like Brazil, are also taking steps toward transforming biofuels into a ‘full-fledged world commodity". However, actions by some countries to protect their domestic markets are reported to be "distorting the international market of commodities."

Domestic standards and domestic conformity assessment procedures are generally set up to improve production and promote international trade relations. However, these domestic standards could also act as "unnecessary barriers to trade".   In the biofuels sector, for example, some domestic standards are based on lack of information, such as in the case of ethanol, where stringent standards for beverage ethanol (for human consumption) are also imposed on biofuel ethanol (which is not for human consumption). There is also a "problem of lack of confidence in the analyses conducted by the laboratories. In order to overcome/reduce these obstacles, the authors recommend "the definition and implementation of world wide harmonized technical standards"  for biofuel products. These technical standards within an international system of metrology, could serve as "reference for safety, quality and compatibility", and may also be a "pivotal instrument for international trade.

The standardization process is said to be based on the complementarities of three "spheres": (1) a regulatory agency (which defines parameters and limits), (2) a technical standardization forum (which defines the needed analytical methods), and (3) a national metrology institute (which provides confidence and guarantee on measurements). More information can be obtained from their policy paper (URL above).

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Researchers from Duke University, Arizona State University, Stanford University (United States) propose a new method for labelling socio-environmental impacts of consumer products which can be considered as an improvement to the currently used "ecolabelling" method. Biofuels could also have this type of labeling. The proposed method (which uses a "multi-attribute"approach) is called, "sustainability product indexing".

The production of consumer products are reported to have associated socio-environmental impacts, some of which are (1 ) emission of greenhouse gas (GHG) emissions due to production, (2) pesticide pollution, water depletion and deforestation (from production of some agricultural consumer products), and (3) concern about "opportunism" by manufacturing companies against workers in developing countries.

"Ecolabelling" of products certifies that a particular product meets a certain standard (with respect to environmental and social impact) and this has been used for many years to assess sustainability of production of many consumer products. The researchers noted from previous reports, however, that ecolabelling policies generally focus on a single impact area, i.e., a single attribute (for example, greenhouse gases), and may "create unexpected shifts in the behavior of the resource users that render the policy ineffectual at best and damaging at worst".

Using a multi-attribute approach, a sustainable product index could "capture " the socio-environmental impacts from a complex supply chain of production of a particular product, by having one or only a few labels that cover all impacts of production on the environment." The researchers provide an overview of this approach by contrasting the traditional single-attribute label versus the proposed multi-attribute sustainable indexing approach. Details are found in their published paper in the "Ecology and Society" journal (URL above).

Energy Crops and Feedstocks for Biofuels Production

Mixed-prairie species (MPS, containing grass and legume plant species) have been reported to grow well on agriculturally degraded lands with minimal fertilization and low agricultural inputs. Such "species mixtures"  have also been found to exhibit high levels of biodiversity (notably those including legumes) which "benefit from a self-supply of nitrogen, potentially reducing or eliminating the need for nitrogen fertilizer". These features (i.e., thriving on marginal lands, low agricultural inputs) make MPS as good biofuel feedstocks. Cultivation of these bioenergy crops do not compete with agriculturally productive land. The performance of mixed MPS  feedstocks to release ethanol-fermentable sugars (after pretreatment) is not yet well studied.

Scientists from the University of California, Riverside (United States) evaluated the sugar release of some dominant species in an MPS-plot after hydrothermal pretreatment (heating with water at 180oC) and enzymatic saccharification. Hydrothermal pretreatment "deconstructs" the plant cell walls, exposing the carbohydrate polymers, while enzymatic saccharification breaks-down the carbohydrates into simple sugars for ethanol fermentation. The following plants from an MPS plot were studied: (1) a C3 grass (Poapratensis), (2) a C4 grass (Schizachyrium scoparium), and (3) a legume (Lupinus perennis).

The researchers found that the two grasses "contained higher levels of sugars than did the legume, and also exhibited higher sugar yields as a percentage of the maximum possible from combined pretreatment and enzymatic hydrolysis. They also found that the stems of the two grasses and the legume exhibited higher "recalcitrance" (resistance to plant cell wall deconstruction) compared to other parts of the plant. Thus, plant anatomy was concluded to be an important factor for both glucan digestibility and glucose mass release in the MPS plants studied. The full paper is published in the open access journal, Biotechnology for Biofuels (URL above).

Biofuels Processing

Researchers from the Chinese Academy of Sciences and the University of Science and Technology in China report the use of an organic electrolyte solution (OES) for treating microcrystalline cellulose,  in an attempt to destroy its crystal structure before enzymatic saccharification. Enzymatic saccharification converts cellulose into simple sugars, which can be fermented into biofuel ethanol. Destruction of the cellulose crystalline structure might increase the sugar conversion during enzymatic saccharification. This study in a model system could provide insights into what might happen to cellulose in actual plant lignocellulosic biomass.

The organic electrolyte solution was composed of an ionic liquid (1-allyl-3- methylimidazolium chloride ([AMIM]Cl) and an organic solvent (dimethyl sulfoxide; DMSO). Results showed that the OES rapidly dissolved the cellulose, to achieve a glucose yield of 51.4%, which was only slightly lower than the glucose yield obtained from a pure ionic liquid (59.6%). The researchers concluded that OES pretreatment can be a cost effective and environmentally friendly technique for cellulose hydrolysis due to 1) its lower cost when compared to the use of pure ionic liquids, (2) short dissolution time, (3) lower energy requirements for stirring and transporting, and (4) recyclability. The full results are published in the open access journal, Biotechnology for Biofuels (URL above).

In the production of cellulose-ethanol (orethanol from plant cellulosic biomass), cellulolytic enzymes (collectively called, "cellulases") are used to convert the cellulose molecules in the biomass into simple sugars that can be fermented to ethanol. The search for more effective cellulolytic enzymes from novel sources is an area of active research, as these new enzymes might lower the production cost of cellulose ethanol.

A collaborative team of scientists from different universities and research institutes in Brazil, are looking at Brazilian termites and screening termite-gut extracts for good cellulolytic activities which might find potentially useful and commercial applications. They noted however, that in the determination of cellulotyic enzyme activities using commercially available substrates (such as carboxymethyl cellulose), the reported activities do not always correspond to activities against natural lignocellulosic substrates. They also noted that the ‘macroscopic characteristics of the raw material, such as insolubility and heterogeneity, hinder its use for high throughput screenings". Thus, they attempted to develop a more"natural" substrate with better macroscopic homogeneity, for use in determining cellulolytic enzyme activities, as a possible replacement to commercial (non-natural) cellulose-based substrates. They tried to use "colloidal sugar cane bagasse" (CSCB) as the substrate for enzyme activity measurements, in their high throughput screenings of Brazilian termites. The researchers mentioned that the preparation of CSCB involved "minimal chemical change in the lignocellulosic material".

The results of their study showed that "important differences between the use of the natural substrate and commercial cellulase substrates, such as carboxymethyl cellulose or crystalline cellulose, were observed". They were also able to demonstrate that CSCB can be a useful substrate in high throughput assays. Based on their screening studies using CSCB, they found that wood feeding termites (in contrast to litter feeding termites) "may not be the best source for enzymes which can degrade sugarcane biomass". The full paper is published in the open access journal, Biotechnology for Biofuels (URL above).

Biofuels Policy and Economics

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Researchers from the Iowa State University (United States) report the use of a slightly different approach to the Life Cycle Assessment (LCA) study on biofuel production from corn. In their study, they looked at the "per-unit-land-area"-based (rather than "per-unit-energy"-based) LCA for the production of two types of biofuel production pathways from corn: (1) bioethanol from the processing of corn starch and (2) a refinable "bio-oil" for biogasoline production (with a "biochar" solid by-product) from the thermal (pyrolytic) processing of cornstover (stalks/leaves after harvest). Here, not one, but two biofuel feedstocks from a single bioenergy crop (the corn plant) are utilized for biofuel production:  (1) the starchy corn grains for bioethanol, and (2) the lignocellulosic cornstover for pyrolytic "bio-oil" production.

The motivation behind the use of the "per-unit-land-area" basis in LCA stems from the observation that the common LCA method using the "per-unit-energy"basis has some limitations. According to the authors, "a significant shortcoming of this approach to current LCAs is that they do not allow emissions measurement for a biofuel pathway that utilizes more than one feedstock. In agriculture, specifically, it makes sense to consider the possibility of utilizing more than one feedstock for biofuel production given that land is a scarce resource". The results of their study showed that the "two biofuels-one energy crop" pathway for biofuels production from corn achieves a 52.1% reduction in GHG emissions, and that this production pathway could qualify as an "advanced biofuel". The complete study is published in the journal, Fuel (URL above).