A team of Chinese scientists achieved higher cellulosic ethanol yield from biodegradation of poplar wood chips pretreated with white rot fungus compared to non-treated control, reports the journal Biotechnology for Biofuels.

Biological pretreatment with white rot fungi has been recognized as a potential method of enhancing the degradation of lignocellulose feedstock prior to fermentation of released sugar molecules into ethanol. Lignocellulose is a major component of woody biomass used as second generation biofuel feedstock. The lignin polymer strongly intermesh with cellulose, and hemicellulose components of lignocellulose is a tough barrier that prevents access to target sugar during fermentation process. Biological agents like white rot fungi that aid in wood decay process are known to possess natural enzymes capable of opening the complex structure of lignin molecules.

The Chinese scientists pretreated the milled triploid poplar wood with the white rot fungal isolate designated as Trametes velutina D10149 and incubated the mixture for 4 to16 weeks. Ethanol production was measured following simultaneous saccharification and fermentation (SSF) wherein enzymatic breakdown of cellulose and fermentation of sugar into ethanol were run at the same time. While fungal pretreatment did not significantly degrade the lignin, the ethanol yield from SSF was higher (21 to 75 percent) for pretreated samples compared to the untreated control (18 percent). The poplar sample biodegraded for 16 weeks after 24-hour SSF yielded a conversion rate of 34.8 percent. The researchers assumed that the modification of lignin structure during fungal treatment had played a key role in improving cellulose bioconversion rates.

An international consortium of scientists published in the journal Bioenergy Research the first complete genetic maps of switchgrass (Panicum virgatum L.). Switchgrass is a potential biofuel feedstock crop, based on a mapping population derived from a cross between a lowland and an upland ecotype.

Switchgrass is a perennial grass species that has been the target of intensified research since 1992 when the U.S. Department of Energy selected this species as the herbaceous model for its Biofuels Feedstock Development Program. Switchgrass bioenergy research has been geared towards the improvement of its biomass yield and the reduction of recalcitrance - described as the unavailability of sugars trapped in the cellulosic biomass that hinders bioethanol production. Guided by these objectives, an international team of switchgrass researchers embarked on a genetic mapping study to further unlock the many secrets of switchgrass genome. These may hold the keys for both biomass yield and ethanol conversion efficiency.

The published genetic map was generated using a full-sib mapping population derived from a cross between two contrasting cultivars - the lowland ‘Alamo' (AP13) and the upland ‘Summer' (VS16). Comparative analyses between the AP13 and VS16 maps show high colinearity between the two maps with similar marker orders and recombination rates. This suggests that genetic exchanges between the two ecotypes should occur freely and hence genetic improvement through transfer of favorable traits from the higher biomass yielding lowlands into the more cold tolerant uplands and vice versa should be attainable.

The mapped genetic markers will provide useful information not only toward the advancement of switchgrass genome science but more practically for identifying the genes associated with biomass and quality traits for bioenergy utilization.

In the recent issue of Nature Genetics, a team of scientists comprising the International Peach Genome Initiative published the 265-million base genome sequence of the Lovell variety of peach (Prunus persica). In line with this development, scientists at the US Department of Energy Joint Genome Institute (DOE JGI) are now looking at how the peach sequence can be used to study genes found in related tree species that can be tapped as biofuel feedstocks.

Poplar tree, a potential source of second generation biofuel feedstock and one of the flagship species of the DOE JGI, has remarkable resemblance to peach in terms of DNA sequence similarity, according to Jeremy Schmutz, head of the Plant Program at the DOE JGI and member of the consortium that sequenced the peach genome. For this reason, researchers can use the peach sequence not only for peach genetics per se but also for deepening our understanding of the basic biology of the poplar tree toward greater efficiency in biofuel conversion. Peach can be used as a plant model for studying genes found in poplar and such knowledge can be applied for breeding efficient trees. For instance, as current studies show, the peach genome potentially provides insights into metabolic pathways that lead to lignin biosynthesis – the key barrier to conversion of wood biomass to bioethanol.

One of the traits the DOE JGI scientists are particularly interested in is the so-called "evergreen" gene in peach which prolongs the plant's growing season. The idea is to use the peach "evergreen" gene sequence as a hint to hunt a similar gene in poplar. According to Daniel Rokhsar, DOE JGI Eukaryotic Program head, the "evergreen" trait could be manipulated in poplar to increase its biomass yield for biofuel production.

Civil engineers at Kansas State University are testing the idea of using the byproducts of cellulosic ethanol production as partial replacement for cement to make concrete. They say that it can reduce the concrete's carbon footprint and make the concrete more rigid.

The researchers are exploring the use of leftover material from production of cellulosic ethanol, which is biofuel produced from non-food biomass such as wood chips, grass straw and other agricultural residue. The leftover from cellulosic ethanol process contains lignin and some cellulose and this material is typically burned to generate electricity or disposed as ash. The researchers found that high-lignin ash mixed with portland cement formed a chemical reaction that made the concrete more rigid. The experiment showed that replacing 20 percent of the cement with cellulosic leftover after burning increased the strength of the concrete by 32 percent.

According to the KSU engineers, the potential of cellulosic ethanol byproduct to increase the durability of concrete will not only reap value added benefits for both the ethanol and concrete industry but also for the environment. They say that concrete production is rampant and cement production requires lot of energy. While making concrete is less energy intensive than making steel or other building materials, it potentially contributes between 3 to 8 percent to global carbon dioxide emissions since it is the most widely used industrial material after water. By using alternative materials such as the leftover lignin ash, dependence on cement and hence the carbon footprint of concrete materials can be reduced.

US-based SG Biofuels, Inc. has confirmed significant genetic diversity in its Jatropha curcas germplasm collection based on the genetic analysis of over two million Single Nucleotide Polymorphism (SNP) markers.

In contrast to previous findings pointing to a narrow genetic base for Jatropha curcas germplasm, the present molecular studies suggest that its genetic variability could be comparable to that of corn and other domesticated crops and the genetically diverse materials would be suited for breeding toward significant yield improvement. Increasing the yield of Jatropha curcas can further boost its biofuel output. The finding also means that breeders could further exploit hybrid vigor by crossing genetically diverse parental materials in order to deliver elite hybrid planting materials. SGB has been generating hybrid varieties of Jatropha and current trials in Brazil, India and Central America have indicated promising results for its first-generation hybrids.

SGB is a bioenergy crop company that delivers high performance solutions for the renewable fuel, biomass and chemical markets. The company has been implementing high-throughput technologies for its molecular and genetic studies. It is currently embarking on a large-scale Jatropha genome sequencing program that will ultimately assign genetic markers to valuable agronomic traits and plant attributes in order to speed up the genetic improvement of its elite hybrid cultivars. In another technological feat, SGB scientists have developed a state of the art genotyping platform that enables rapid and precise DNA barcoding of parental and hybrid lines with unique digital sequence identifiers.