Will Washington Provide Its Own Feedstocks for Biofuels?

The study finds that Washington State’s field corn, sugar beet and canola production could satisfy only a small percentage of the State’s annual gasoline or diesel consumption. Linear programming projections for 2008 showed a relatively close match between projected and actual production. Projections for 2009-2011 showed no increase in the State’s capacity to increase biofuel crop feedstocks. In comparison to crop feedstocks, Washington’s total annual lignocellulosic biomass is abundant. However, only a fraction of the biomass could be converted to biofuel due to high costs of collection and processing, competing markets for some biomass, and limitations in current technology.biofuels, biofuel feedstocks, canola, cellulosic inventories, grain corn, linear programming, Washington State

Mechanism, kinetics and microbiology of inhibition caused by long-chain fatty acids in anaerobic digestion of algal biomass

BACKGROUND: Oleaginous microalgae contain a high level of lipids, which can be extracted and converted to biofuel. The lipid-extracted residue can then be further utilized through anaerobic digestion to produce biogas. However, long-chain fatty acids (LCFAs) have been identified as the main inhibitory factor on microbial activity of anaerobic consortium. In this study, the mechanism of LCFA inhibition on anaerobic digestion of whole and lipid-extracted algal biomass was investigated with a range of calcium concentrations against various inoculum to substrate ratios as a means to alleviate the LCFA inhibition. RESULTS: Whole algal biomass of Nannochloropsissalina represents high lipid content algal biomass while lipid-extracted residue represents its low lipid counterpart. The anaerobic digestion experiments were conducted in a series of serum bottles at 35 °C for 20 days. A kinetic model, considering LCFA inhibition on hydrolysis, acidogenesis as well as methanogenesis steps, was developed from the observed phenomenon of inhibition factors as a function of the LCFA concentration and specific biomass content or calcium concentration. The results showed that inoculum to substrate ratio had a stronger effect on biogas production than calcium, and calcium had no effect on biogas production when inoculum concentration was extremely low. The microbial community analysis by high-throughput Illumina Miseq sequencing indicated that diversity of both bacterial and methanogenic communities decreased with elevation of lipid concentration. Hydrolytic bacteria and aceticlastic methanogens dominated bacterial and archaea communities, respectively, in both high and low LCFA concentration digesters. CONCLUSIONS: This study demonstrated that inoculum concentration has a more significant effect on alleviating LCFA inhibition than calcium concentration, while calcium only played a role when inoculum concentration met a threshold level. The model revealed that each functional microbial group was subject to different levels of LCFA inhibition. Although methanogens were the most susceptible microbes to LCFA inhibition, the inhibition factor for hydrolytic bacteria was more highly affected by inoculum concentration. The microbial community analysis indicated that the bacterial community was affected more than the methanogenic community by high LCFAs concentration. Syntrophic acetogens were sensitive to high LCFA concentrations and thus showed a decreased abundance in such an environment. [Figure: see text

Setting the Theoretical Foundations of Importing Research: Past Evaluation and Future Perspectives

Although prior efforts have been made to review research on importing, an updated, integrated, and chronological assessment of its theoretical evolution is lacking. This study critically investigates the theoretical foundations of importing research using a comprehensive review of 321 importing-related articles published during the 1960–2010 period. The analysis reveals that, although in general this research adopts a certain theoretical perspective, a notable part of it is not theoretically anchored. Of those studies that rely on theories, the most commonly used are the neoclassical microeconomic model, the behavioral model, and transaction cost economics. These theories were mainly associated with international buying behavior, importer–exporter relationships, and strategic aspects of importing. The study also identifies a range of other important topics that could be investigated using extant theories. In addition, the authors propose several other theories not previously employed, such as the institutional, stakeholder, and resource dependence theories, to be used in the study of new research issues. Finally, the authors suggest several actions toward theory advancement, including the need to integrate multiple theoretical paradigms, adjust theory to different environments, combine quantitative and qualitative inputs, cross-fertilize ideas from various disciplines, and periodically assess developments in the importing literature