Biorefining of wheat straw:accounting for the distribution of mineral elements in pretreated biomass by an extended pretreatment–severity equation

BACKGROUND: Mineral elements present in lignocellulosic biomass feedstocks may accumulate in biorefinery process streams and cause technological problems, or alternatively can be reaped for value addition. A better understanding of the distribution of minerals in biomass in response to pretreatment factors is therefore important in relation to development of new biorefinery processes. The objective of the present study was to examine the levels of mineral elements in pretreated wheat straw in response to systematic variations in the hydrothermal pretreatment parameters (pH, temperature, and treatment time), and to assess whether it is possible to model mineral levels in the pretreated fiber fraction. RESULTS: Principal component analysis of the wheat straw biomass constituents, including mineral elements, showed that the recovered levels of wheat straw constituents after different hydrothermal pretreatments could be divided into two groups: 1) Phosphorus, magnesium, potassium, manganese, zinc, and calcium correlated with xylose and arabinose (that is, hemicellulose), and levels of these constituents present in the fiber fraction after pretreatment varied depending on the pretreatment-severity; and 2) Silicon, iron, copper, aluminum correlated with lignin and cellulose levels, but the levels of these constituents showed no severity-dependent trends. For the first group, an expanded pretreatment-severity equation, containing a specific factor for each constituent, accounting for variability due to pretreatment pH, was developed. Using this equation, the mineral levels could be predicted with R(2) > 0.75; for some with R(2) up to 0.96. CONCLUSION: Pretreatment conditions, especially pH, significantly influenced the levels of phosphorus, magnesium, potassium, manganese, zinc, and calcium in the resulting fiber fractions. A new expanded pretreatment-severity equation is proposed to model and predict mineral composition in pretreated wheat straw biomass

Gender and HIV-associated pulmonary tuberculosis: presentation and outcome at one year after beginning antituberculosis treatment in Uganda

BACKGROUND: Tuberculosis is responsible for more female deaths around the earth than any other infectious disease. Reports have suggested that responses to tuberculosis may differ between men and women. We investigated gender related differences in the presentation and one year outcomes of HIV-infected adults with initial episodes of pulmonary tuberculosis in Uganda. METHODS: We enrolled and followed up a cohort of 105 male and 109 female HIV-infected adults on treatment for initial episodes of culture-confirmed pulmonary tuberculosis between March 1993 and March 1995. A favorable outcome was defined as being cured and alive at one year while an unfavorable outcome was not being cured or dead. Subjects were followed-up by serial medical examinations, complete blood counts, serum β(2) microglobulin, CD4+ cell counts, sputum examinations, and chest x-rays. RESULTS: Male patients were older, had higher body mass indices, and lower serum β(2) microglobulin levels than female patients at presentation. At one year, there was no difference between male and female patients in the likelihood of experiencing a favorable outcome (RR 1.02, 95% CI 0.89–1.17). This effect persisted after controlling for symptoms, serum β(2) microglobulin, CD4+ cell count, and severity of disease on chest x-ray (OR 1.07, 95% CI 0.54–2.13) with a repeated measures model. CONCLUSIONS: While differences existed between males and females with HIV-associated pulmonary tuberculosis at presentation, the outcomes at one year after the initiation of tuberculosis treatment were similar in Uganda. Women in areas with a high HIV and tuberculosis prevalence should be encouraged to present for screening at the first sign of tuberculosis symptoms

Biological and Non-Biological Methods for Lignocellulosic Biomass Deconstruction

Owing to their abundance and cost-effectiveness, lignocellulosic materials have attracted increasing attention in clean energy technologies over the last decade. However, the complex polymer structure in these residues makes it difficult to extract the fermentable sugars. Therefore, various pretreatment regimes have been used resulting in the breaking of lignocelluloses’ physical and chemical structures, thereby enhancing the availability of the polysaccharides which are subsequently hydrolysed into different biocommodities. This chapter provides an evaluation of some of the latest exploited methodologies that are used in the pretreatment of lignocellulosic materials. Moreover, the chapter discusses the advantages and disadvantages of each method

A techno-economic evaluation of the effects of centralized cellulosic ethanol and co-products refinery options with sugarcane mill clustering

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)This work compares the calculated techno-economic performance for thermochemical and biochemical conversion of sugarcane residues, considering future conversion plants adjacent to sugarcane mills in Brazil. Process models developed by the National Renewable Energy Laboratory were adapted to reflect the Brazilian feedstock composition and used to estimate the cost and performance of these two conversion technologies. Models assumed that surplus bagasse from the mill would be used as the feedstock for conversion, while cane trash collected from the field would be used as supplementary fuel at the mill. The integration of the conversion technology to the mill enabled an additional ethanol production of 0.033 m(3) per tonne of cane for the biochemical process and 0.025 m(3) t(-1) of cane plus 0.004 m(3) t(-1) of cane of higher alcohols for the thermochemical process. For both cases, electricity is an important co-product for the biorefinery, but especially for biochemical conversion, with surpluses of about 50 kWh t(-1) of cane. The economic performance of the two technologies is quite similar in terms of the minimum ethanol selling price (MESP), at 318 $m(-3) (United States 2007 dollars) for biochemical conversion and 329$ m(3) for thermochemical conversion. (C) 2010 Elsevier Ltd. All rights reserved.34810651078Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)U.S.-Brazil Bilateral Colaboration in Advanced Biofuels and Strategic Analysis NRELU.S. Department of Energy Biomass ProgramConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CNPq [201362/2008-2

A comparison of commercial ethanol production systems from Brazilian sugarcane and US corn

Global biofuels production grew rapidly from 2007 to 2012, led by the United States and Brazil, the world's two largest fuel-ethanol-producing systems. In this paper we provide insights into the characteristics of mature Brazilian sugarcane and maturing US dry mill corn ethanol industries. Both systems continue to improve as measured by life cycle data such as total renewable energy produced per unit of fossil energy consumed [renewable energy ratio (RER)]. Sugarcane self-benchmarking systems showed RER values of 7.0 in 2002 to 9.4 in 2009 as the industry started to switch to mechanized harvesting. The average US RER improved from 1.1 to 1.7 from 2000 to 2010. RERs of 4.4 to 5.5 are observed in corn ethanol plants employing natural gas or corn stover combined heat and power. Ethanol systems configured to produce ethanol and electricity had similar net energy balances (a ratio of net energy produced to energy contained in the fuel). One measure of greenhouse gas (GHG) emissions reductions (biomass use efficiency) compares the effectiveness of displacing carbon from combustion of fossil fuels with renewable carbon. Advanced corn ethanol systems reach higher GHG emission reduction levels compared to sugarcane ethanol by displacing coal-based electricity. Sugarcane systems achieve double the GHG emissions reductions per unit of harvested land relative to corn ethanol because sugarcane and corn are grown as perennial and annual crops in tropical and temperate climatic zones, respectively. Carbon dioxide capture and storage systems could offer additional GHG emission reductions for both corn and sugarcane ethanol systems. (c) 2013 Society of Chemical Industry and John Wiley & Sons, Ltd8220522

Life cycle assessment of Brazilian sugarcane products: GHG emissions and energy use

Sugarcane is currently the main renewable energy source in Brazil. Due to the importance of the cane industry and its contribution to a wide range of biobased energy and other products, LCA studies regarding cane-derived products are needed to assess their environmental benefits. The main objective of this work was the assessment of life cycle energy use and greenhouse gas (GHG) emissions related to cane sugar and ethanol, considering bagasse and electricity surpluses as coproducts. We performed an overall balance for the Brazilian Center-South Region, adopting different methods to evaluate sugar and ethanol production separately. The GREET 1.8c.0 model was used for the 'well-to-wheels' calculations but adapted to the comprehensive set of Brazilian parameters that best represent the Center-South Region. For the reference case, fossil energy use and GHG emissions related to sugar production were evaluated as 721 kJ/kg and 234 g CO(2)eq/kg, respectively. For the ethanol life cycle, these values were 80 kJ/MJ and 21.3 g CO(2)eq/MJ. Special attention was paid to the variation of some parameters among producing units based on data collected by industry. The consequent uncertainties in ethanol life cycle emissions were assessed through a Monte Carlo analysis based on assigned distribution of probability curves for eleven selected parameters and informed by partial statistical data available from industry for distribution generation. Projections were also made for 2020 scenario parameters based on the best in current class technologies and technological improvements deemed commercially possible today. Published in 2011 by John Wiley & Sons, Ltd55519532Office of the Biomass Program of the U.S. Department of Energy as part of the Brazil-USA Memorandum of Understanding to Advance Biofuels Cooperatio

Economic performance and GHG emission intensity of sugarcane- and eucalyptus-derived biofuels and biobased chemicals in Brazil

Biomass feedstock can be used for the production of biofuels or biobased chemicals to reduce anthropogenic greenhouse gas (GHG) emissions. Earlier studies about the techno-economic performance of biofuel or biobased chemical production varied in biomass feedstock, conversion process, and other techno-economic assumptions. This made a fair comparison between different industrial processing pathways difficult. The aim of this study is to quantify uniformly the factory-gate production costs and the GHG emission intensity of biobased ethanol, ethylene, 1,3-propanediol (PDO), and succinic acid, and to compare them with each other and their respective fossil equivalent products. Brazilian sugarcane and eucalyptus are used as biomass feedstock in this study. A uniform approach is applied to determine the production costs and GHG emission intensity of biobased products, taking into account feedstock supply, biobased product yield, capital investment, energy, labor, maintenance, and processing inputs. Economic performance and net avoided GHG emissions of biobased chemicals depend on various uncertain factors, so this study pays particular attention to uncertainty by means of a Monte Carlo analysis. A sensitivity analysis is also performed. As there is uncertainty associated with the parameters used for biobased product yield, feedstock cost, fixed capital investment, industrial scale, and energy costs, the results are presented in ranges. The 60% confidence interval ranges of the biobased product production costs are 0.64–1.10 US$kg −1 ethanol, 1.18–2.05 US$ kg −1 ethylene, 1.37–2.40 US$kg −1 1,3-PDO, and 1.91–2.57 US$ kg −1 succinic acid. The cost ranges of all biobased products partly or completely overlap with the ranges of the production costs of the fossil equivalent products. The results show that sugarcane-based 1,3-PDO and to a lesser extent succinic acid have the highest potential benefit. The ranges of GHG emission reduction are 1.29–2.16, 3.37–4.12, 2.54–5.91, and 0.47–5.22 CO 2eq kg −1 biobased product for ethanol, ethylene, 1,3-PDO, and succinic acid respectively. Considering the potential GHG emission reduction and profit per hectare, the pathways using sugarcane score are generally better than eucalyptus feedstock due to the high yield of sugarcane in Brazil. Overall, it was not possible to choose a clear winner, (a) because the best performing biobased product strongly depends on the chosen metric, and (b) because of the large ranges found, especially for PDO and succinic acid, independent of the chosen metric. To quantify the performance better, more data are required regarding the biobased product yield, equipment costs, and energy consumption of biobased industrial pathways, but also about the production costs and GHG emission intensity of fossil-equivalent products.BT/Biotechnology and Societ