News and Trends

"Helioculture" is a recent buzzword that is creating ripples of curious interest in the biofuels world. The technology was recently launched by an American start-up company, Joule Biotechnologies. An interesting innovation in the technology is its capability to convert solar energy directly into biofuels without any intermediate processing steps in between. In conventional biofuels processing, solar energy is first utilized to cultivate a bioenergy feedstock (i.e. a crop or algae). The feedstock is then converted into the target biofuel, through a long series of biological (microbial/enzymatic) or thermo-chemical processing steps. These intermediate steps contribute substantially to the cost of the biofuel. The direct conversion process in helioculture does away with the intermediate steps, and is therefore seen to substantially reduce biofuel processing costs and improve sustainability of biofuel production. The system essentially consists of a solar converter (in a solar panel configuration) that is filled with brackish water, nutrients and an "engineered" photosynthetic organism which directly converts solar energy and CO2 into liquid biofuels (schematic diagram in related information URL below). Among the attractive features of the "direct-to-fuel-conversion" of helioculture are: (1) no freshwater requirement, (2) minimal land use needed for production, (3) "avoids costly intermediate processing" steps that are usually present in other biofuel production processes, and (4) "enables the scale, unlimited quantities and pricing required for energy independence".

Related information: How Heliotechnology Works (schematic diagram)
(full article in provisional pdf version during time of access)

In the development of "second generation biofuel ethanol" from lignocellulosic biomass, scientists are actively finding ways to break the "recalcitrance" in plant cell walls which is considered as a major barrier against cost-effective "cellulose-ethanol" production. This "recalcitrance" is attributed to the tight lignin wrapping surrounding the well-ordered, crystalline arrangement of cellulose molecules (together with hemicelluloses and pectins) in the plant cell wall. "The chemical and structural characteristics of these plant cell wall constituents remain largely unknown today". Understanding these characteristics can open new doors for the development of better pretreatment methods to break recalcitrance. Scanning probe microscopy techniques can be a powerful tool for understanding the plant wall characteristics which contribute to recalcitrance. John Yarbrough and colleagues in the Chemical and Biosciences Center, National Renewable Energy Center (Colorado, USA) recently reviewed some tools in scanning probe microscopy which can be applied for the characterization of plant cell wall structures in lignocellulosic bioenergy feedstocks. They also discussed "future developments based on scanning probe microscopy techniques that combine linear and nonlinear optical techniques to characterize plant cell wall nanometer-scale structures, specifically aperture-less near-field scanning optical microscopy and coherent anti-Stokes Raman scattering microscopy". A full copy of the review can be accessed in the open access journal website, Biotechnology for Biofuels (URL above)..

The Scottish government website reports the official opening of the Scottish European Green Energy Center (SEGEC). A 1.6 million investment for the center by the European Regional Development Fund was also announced. The center "aims to help the Scottish green energy sector secure maximum benefits from engagement with Europe through developing partnerships with businesses and institutions, designing collaborative projects and identifying and accessing European funding". Based at the University of Aberdeen, research and development projects will focus on: "marine energy, offshore wind, long distance super grid development and smart distribution grids, carbon capture and storage, renewable heat and energy efficiency". According to First Minister Alex Salmond, the center would strengthen Scotland's position as a leader in sustainable energy demonstration and deployment..

Energy Crops and Feedstocks for Biofuels Production
(full article in provisional pdf version during time of access)

Researchers from the Southern Central Agricultural Research Laboratory of the United States Department of Agriculture Agricultural Research Service (USDA-ARS) have found that "reject" watermelon juice can be used as a direct feedstock, or as a nitrogen supplement for the production of ethanol by fermentation. Certain economic scenarios are said to contribute to the potential of waste watermelon juice as a valuable resource for ethanol production. About 20% of the annual watermelon crop become "rejects" (due to surface blemishes present or the fruit is out of shape). Lycopene and L-citrulline (value-added "nutraceuticals" for health) can be potentially extracted from the "reject" watermelon juice, resulting in the generation of about 500 liters of "cull watermelon wastewater" per ton of "reject" watermelon processed. The wastewater is said to contain 7% to 10% (w/v) of fermentatble sugars and 15 micromole/L to 35 micromole/L of free amino acids. The sugar content makes the wastewater a good saccharine feedstock for ethanol fermentation, and the amino acid content also makes it a good nitrogen supplement for ethanol fermentation. The researchers found that lycopene-free watermelon juice with the residual amino acids were "readily fermentable as the sole feedstock or as diluent, feedstock supplement, and nitrogen supplement to granulated sugar or molasses". "Utilizing watermelon juice as diluent, supplemental feedstock, and nitrogen source for fermentation of processed sugar or molasses allowed complete fermentation of up to 25% (w/v) sugar concentration at pH 3 (0.41 to 0.46 g ethanol per g sugar) or up to 35% (w/v) sugar concentration at pH 5 with a conversion to 0.36 to 0.41 g ethanol per g sugar". The full paper can be accessed in the open access journal website, Biotechnology for Biofuels (URL above)..

Biofuels Processing

Butanol is a 4-carbon alcohol, which is considered a better biofuel than its 2-carbon counterpart, ethanol. It is usually produced by ABE (acetone-butanol-ethanol) fermentation using agricultural feedstocks, by bacteria called, Clostridia. Among butanol's better biofuel characteristics (relative to ethanol) are: (1) higher energy density, (2) higher hydrophobicity (doesn't attract water, therefore, can be shipped in existing fuel piepelines; also less corrosive and blends better with gasoline at higher levels). However, the barriers which hinder commercialization of butanol production are its low yield, low productivity and low titer, due to the product toxicity of the fermenting microorganisms. Low titers are said to increase the cost of separating butanol from the fermentation broth. Scientists from the Ohio State University attempted to improve butanol productivity and titer using a single-path continuous fermentation operation in a fibrous bed bioreactor (FBB). They immobilized a non-spore-forming mutant strain of Clostridium beijerinckii in the fibrous bed bioreactor (FBB), and optimized the process (in terms of culture medium and operating conditions) for increased butanol production. The scientists also mentioned that the "mutator strain in combination with the FBB-based adaptation method, will help more rapid evolution of the [butanol]-producing Clostridium beijerinckii towards higher butanol tolerance..

In temperate countries, grain is often harvested with high moisture content, and then dried to extend storage life. Drying is an intensive energy-consuming process. If the grain is to be utilized for ethanol production, the drying process would contribute significantly to the cost of production. Scientists from the Swedish University of Agricultural Sciences investigated the use of an airtight storage method of moist wheat grain with the addition of a biocontrol agent (a yeast called, Pichia anomala), and its impact on ethanol production was assessed. As a biocontrol agent, the antifungal property of P. anomala is said to effectively prevent mold infestation on the grains. The results showed that the "ethanol yield from moist wheat [obtained from the alternative storage method] was enhanced by 14% compared with the control obtained from traditionally (dry) stored grain". The researchers also found that the addition of the biocontrol agent (P. anomala) did not affect the improvement in ethanol yield. Furthermore, the pre-treated moist grain had a better saccharification (i.e. starch-to-sugar-conversion) after enzyme (amylase) addition, compared to dry grain. The findings indicate that the alternative storage method of moist wheat grain can substantially reduce energy costs attributed to drying. The scientists said that this "provides a new opportunity to increase the sustainability of bioethanol production". The full paper can be accessed in the open access journal website, Biotechnology for Biofuels (URL above).

Biofuels Policy and Economics

An international team of scientists have joined together in a collaborative effort, "to seek resolution of issues related to sustainable production of energy from biomass". The project is called "Global Sustainable Bioenergy: Feasibility and Implementation Paths". The project was launched "in response to the substantial confusion and uncertainty about whether the world should look to bioenergy (biofuels and electricity) to play a prominent role in the future". The project will proceed in 3 phases. Phase 1 will consist of public meetings to map out the project visions, plans to attain the objectives, examine issues within a regional and continental context, form the project team, and recruit support. Phase 2 will attempt to answer the question: "Is it physically possible for bioenergy to meet a substantial fraction of future world mobility and/or electricity demand while our global society also meets other important needs: feeding humanity, providing fiber, maintaining and where possible improving soil fertility, air and water quality, biodiversity and wildlife habitat, and achieving very large greenhouse gas emission reductions that are not substantially negated by land use changes?" In Phase 3 (given an affirmative answer to the question in Phase 2), the analysis will be broadened and teams will be set up as necessary, "to address desirable transition paths and policies, ethical and equity issues, and local-scale analysis including rural economic development". Details of the project can be obtained from the project website (URL above)..