Perennial grasses as lignocellulosic feedstock for second-generation bioethanol production in Mediterranean environment.

In this paper the suitability of three perennial, herbaceous, lignocellulosic grasses ( Arundo donax , Saccharum spontaneous spp. aegyptiacum and Miscanthus x giganteus ) for the production of second-generation bioethanol in semi-arid Mediterranean environment was studied. Crops were established in spring 2002, supplying irrigation and nitrogen fertilization up to 2004/2005 growing season. Subsequently, crops were grown without any agronomic input and harvested annually. Data reported in this paper refers to 2008/2009 and 2009/2010 growing seasons. Aboveground dry matter (DM) yield was higher in Arundo (35.4±2.1 Mg ha –1 in 2009 and 32.2±1.9 Mg ha –1 in 2010 harvest) than in Saccharum (27.3±2.0 and 23.9±1.9 Mg ha –1 , respectively) and Miscanthus (19.6±2.8 and 17.2±1.6 Mg ha –1 , respectively). Structural polysaccharides of the raw material were higher in Miscanthus (63.4% w/w) followed by Saccharum (61.5% w/w) and Arundo (57.6% w/w). The same trend was identified for the cellulose content (41.0%, 36.8% and 34.6%, respectively). The highest values in the total hemicellulose complex were observed in Saccharum (24.7%), followed by Arundo (23.1%) and Miscanthus (22.4%). The composition of structural polysaccharides leads to a higher theoretical ethanol yield (TEY) from one dry ton of Miscanthus feedstock (kg DM Mg –1 ), followed by Saccharum and Arundo . On the other hand, the TEY per unit surface (Mg ha –1 ) was greater in Arundo than in Saccharum and Miscanthus . When compared to other lignocellulosic sources used in the second-generation bioethanol technology, such as agricultural residues, woody species and other herbaceous perennial crops, Arundo , Saccharum and Miscanthus showed a great potential in terms of TEY ha –1 . Given the high levels of biomass yield and composition of structural polysaccharides, the three species might be introduced into the Mediterranean cropping systems to supply lignocellulosic biomass for second-generation industrial plants or bio-refineries

Urodynamic effects of oxybutynin and tolterodine in conscious and anesthetized rats under different cystometrographic conditions

BACKGROUND: Antimuscarinic agents are the most popular treatment for overactive bladder and their efficacy in man is well documented, producing decreased urinary frequency and an increase in bladder capacity. During cystometry in rats, however, the main effect reported after acute treatment with antimuscarinics is a decrease in peak micturition pressure together with little or no effect on bladder capacity. In the present experiments we studied the effects, in rats, of the two most widely used antimuscarinic drugs, namely oxybutynin and tolterodine, utilising several different cystometrographic conditions. The aim was to determine the experimental conditions required to reproduce the clinical pharmacological effects of antimuscarinic agents, as seen in humans, in particular their ability to increase bladder capacity. RESULTS: Intravenous or oral administration of tolterodine or oxybutynin in conscious rats utilized 1 day after catheter implantation and with saline infusion at constant rate of 0.1 ml/min, gave a dose-dependent decrease of micturition pressure (MP) with no significant change in bladder volume capacity (BVC). When the saline infusion rate into the bladder was decreased to 0.025 ml/min, the effect of oral oxybutynin was similar to that obtained with the higher infusion rate. Also, experiments were performed in rats in which bladders were infused with suramin (3 and 10 μM) in order to block the non-adrenergic, non-cholinergic component of bladder contraction. Under these conditions, oral administration of oxybutynin significantly reduced MP (as observed previously), but again BVC was not significantly changed. In conscious rats with bladders infused with diluted acetic acid, both tolterodine and oxybutynin administered at the same doses as in animals infused with saline, reduced MP, although the reduction appeared less marked, with no effect on BVC. In conscious rats utilized 5 days after catheter implantation, a situation where inflammation due to surgery is reduced, the effect of tolterodine (i.v.) and oxybutynin (p.o.) on MP was smaller and similar, respectively, to that observed in rats utilized 1 day after catheter implantation, but the increase of BVC was not statistically significant. In anesthetized rats, i.v. administration of oxybutynin again induced a significant decrease in MP, although it was of questionable relevance. Both BVC and threshold pressure were not significantly reduced. The number and amplitude of high frequency oscillations in MP were unmodified by treatment. Finally, in conscious obstructed rats, intravenous oxybutynin did not modify frequency and amplitude of non-voiding contractions or bladder capacity and micturition volume. CONCLUSION: Despite the different experimental conditions used, the only effect on cystometrographic parameters of oxybutynin and tolterodine in anesthetized and conscious rats was a decrease in MP, whereas BVC was hardly and non-significantly affected. Therefore, it is difficult to reproduce in rats the cystometrographic increase in BVC as observed in humans after chronic administration of antimuscarinic agents, whereas the acute effects seem more similar

Evaluation Of The Methanogenic Potential Of Two Lignocellulosic Crops

Biogas production can be considered an important technology for the sustainable use of agricultural biomass as a renewable energy source even more when the substrates for anaerobic digestion are crop residues, livestock residues or energy crops that don’t compete with food crops for land use. The aims of this study were to evaluate the production of biogas and biomethane from two lignocellulosic crops suitable for the Mediterranean environment (Arundo donax L. and Saccharum spontaneum subsp. aegyptiacum (Willd.) Hack) and the efficiency of a thermal pretreatment to increase the biomethane production. The purpose of the pretreatment is to break the recalcitrant lignin layer, so that the cellulose and hemicellulose present in the biomass are hydrolyzed by microorganisms and converted into simple sugars to achieve greater energy yield

Future yields assessment of bioenergy crops in relation to climate change and technological development in Europe

Bioenergy crops are expected to play an important role in reducing CO2 emission, in energy supply and in European energy policy. However, a sustainable bioenergy supply must be resilient to climate change and the impacts on agriculture at both global and regional scale. The purpose of this study was to forecast the potential distribution of several bioenergy crops based on agronomic and environmental constrains under current conditions and future scenarios (2020 and 2030) in European Union. Potential biomass yield, according to the category end use product achievable in each environmental zone of Europe at present and in the future available land have been also studied. Future yields were assessed according to two factors: technological development and climate change: the former was based on prospect of DG-Agriculture for conventional crops and expert judgments for bioenergy crops, while the latter based on relevant research papers and literature reviews which used site-specific crop growth models. Yields are expected to increase in northern Europe due to climate change and technological development, while in southerneastern Europe the negative effect of climate change will be mitigated by the technological development. The estimated total biomass production in Europe, on the basis of future yields and surplus land made available for energy crops, may not be sufficient to meet the needs of bioenergy supply as claimed in the European directive 2009/28/EC

Physiological responses of Arundo donax ecotypes to drought: a common garden study

Genetic analyses have suggested that the clonal reproduction of Arundo donax has resulted in low genetic diversity. However, an earlier common garden phenotyping experiment identified specimens of A. donax with contrasting biomass yields (ecotypes 6 and 20). We utilized the same well-established stands to investigate the photosynthetic and stress physiology of the A. donax ecotypes under irrigated and drought conditions. Ecotype 6 produced the largest yields in both treatments. The A. donax ecotypes exhibited identical high leaf-level rates of photosynthesis (PN) and stomatal conductance (Gs) in the well-watered treatment. Soil drying induced reductions in PN and Gs, decreased use of light energy for photochemistry, impaired function of photosystem II and increased heat dissipation similarly in the two ecotypes. Levels of biologically active free-abscisic acid (ABA) and fixed glycosylated-ABA increased earlier in response to the onset of water deficit in ecotype 6; however, as drought progressed, the ecotypes showed similar increases in both forms of ABA. This may suggest that because of the low genetic variability in A. donax the genes responding to drought might have been activated similarly in the two ecotypes, resulting in identical physiological responses to water deficit. Despite the lack of physiological ecotypic differences that could be associated with yield, A. donax retained a high degree of PN and biomass gain under water deficit stress conditions. This may enable utilization of A. donax as a fast growing biomass crop in rain-fed marginal lands in hot drought prone climates

leaf appearance rate and final main stem leaf number as affected by temperature and photoperiod in cereals grown in mediterranean environment

In the present study, a two-year field trial was carried out with the aim to evaluate daylength and air temperature effects on leaf appearance and related rates in two durum wheat (Triticum durum Desf.), two bread wheat (Triticum aestivum L.) and two barley (Hordeum vulgare L.) cultivars, using six different sowing dates (SD). Significant effects of SD on final main stem leaf number (FLN), thermal leaf appearance rate (TLAR), daily leaf appearance rate (DLAR) and phyllochron (PhL) were found. Cultivars resulted inversely correlated to mean air temperature in the interval emergence - fifth leaf full expansion (E-V). Linear response of leaf number over days after sowing was shown for all SD and cultivars, with R2 higher than 0.95. FLN linearly decreased from the first to the last SD for durum wheat, while more variable behaviour was observed in bread wheat. TLAR and DLAR showed a linear increment of the rate from the first to the last SD in durum wheat, while did not for bread wheat and barley. PhL in durum wheat decreased from the first to the last SD. Barley and bread wheat showed the highest values on those SDs which did not reach flowering. The increase of TLAR was affected by photoperiod and photothermal units in durum wheat, while by temperatures only in barley and bread wheat. Present results might find practical application in the improvement of phenology simulation models for durum wheat, bread wheat and barley grown in Mediterranean area in absence of water and nutrient stress