Catalytic two-step process for the production of propylene from bioethanol

Theoretical and Experimental Chemistry - On the basis of analysis and thermodynamic calculations of the reaction paths of the catalytic conversion of ethanol a two-step process is proposed for the...     

An evaluation of british columbian beetle-killed hybrid spruce for bioethanol production

The development of bioconversion technologies for production of fuels, chemicals, and power from renewable resources is currently a high priority for developed nations such as the United States, Canada, and the European Union as a way to improve national energy security and reduce greenhouse gas emissions. The widespread implementation of such technologies will require a sustainable supply of biomass from forestry and agriculture. Forests are a major source of feedstocks for biofuels production in Canada. Woody biomass includes residues from logging and forest thinning, and from wood processing and pulp production. More recently, damaged wood caused by beetle infestations has become available on a large scale in Western Canada. This study evaluates beetle-killed British Columbian hybrid spruce (HS) (Picea glauca x P. engelmannii) as a feedstock for the production of bioethanol. In the past 30 yr, attack by the beetle Dendroctonus rufipennis and associated fungi has resulted in estimated losses of more than three billion board feet in British Columbia alone. Here we describe the chemical and some physical characteristics of both healthy (HHS) and beetle-killed (BKHS) British Columbian HS and evaluate the technical feasibility of using these feedstocks as a source of biomass for bioethanol production. Untreated HHS and BKHS did not differ significantly in chemical composition except for the moisture content, which was significantly lower in BKHS (approx 10%) compared with HHS (approx 18%). However, the yields of carbohydrates in hydrolyzable and fermentable forms were higher at mild pretreatment conditions (H-Factor <1000) for BKHS compared with HHS. At medium (H-Factor 1000-2000) and severe (H-Factor >2000) pretreatment conditions HHS and BKHS behaved similarly. Organosolv pretreated HHS and BKHS demonstrated good ethanol theoretical yields, approx 70 and 80%, respectively.     

Availability of crop residues as sustainable feedstock for bioethanol production in North Carolina

The amount of corn stover and wheat straw that can be sustainably collected in North Carolina was estimated to be 0.64 and 0.16 million dry t/yr, respectively. More than 80% of these crop residues are located in the coastal area. The bioethanol potential from corn stover and wheat straw was estimated to be about 238 million L (63 million gal/yr) in North Carolina. The future location of ethanol plant in North Carolina was estimated based on feedstock demand and collection radius. It is possible to have four ethanol plants with feedstock demand of 400, 450, 500, and 640 dry t/d. The collection radii for these four ethanol plants are 46, 60, 42, and 67 km (28, 37, 26, and 42 miles), respectively. The best location for a bioethanol plant includes four counties (Beaufort, Hyde, Tyrrell, and Washington) with feedstock demand of 500 t/d and collection radius about 26 mile.     

Steam pretreatment of Salix with and without SO2 impregnation for production of bioethanol

In the wood-to-ethanol process, pretreatment of the material is necessary prior to enzymatic hydrolysis to obtain high overall yields of sugar and ethanol. Steam pretreatment of fast-growing Salix either with or without SO₂ impregnation has been investigated by varying different parameters. Overall glucose yields of above 90% and overall xylose yields higher than 80% were obtained both with and without impregnation. However, the most favorable pretreatment conditions for the separate yields of glucose and xylose differed to a lower degree using SO₂-impregnated wood chips, resulting in higher total sugar yield than that obtained with non-impregnated wood chips.     

Improvement of saccharification process for bioethanol production from Undaria sp. by gamma irradiation

Recently, many research works have reported on improvements to the saccharification process that increase bioethanol production from cellulosic materials. Gamma irradiation has been studied as an effective method for the depolymerization of complex polysaccharides. In this study, the effect of gamma irradiation on saccharification of Undaria biomass for bioethanol production was investigated. The Undaria biomass was irradiated at doses of 0, 10, 50, 100, 200 and 500 kGy and then hydrolyzed using sulfuric acid. The effects of gamma irradiation were measured through microscopic analysis to determine morphological changes and concentration of the reducing sugar of hydrolysates. Microscopic images show that gamma irradiation causes structure breakage of the Undaria cell wall. The concentration of reducing sugar of hydrolysates significantly increased as a result of gamma irradiation, with or without acid hydrolysis. These results indicate that the combined method of gamma irradiation with acid hydrolysis can significantly improve the saccharification process for bioethanol production from marine algae materials.     

MnO2纳米粒子固载纤维素酶用于高效水解农业废弃物制备生物乙醇

纤维素酶是一种有效的纤维质类物质水解催化剂,工业应用时可通过固定化纤维素酶来降低其成本。本文将烟曲霉原变种JCF产生的纤维素酶固定在MnO2纳米颗粒上。 MnO2可提高纤维素酶的活性,并充当一个更好的载体。采用扫描电镜表征了所制MnO2纳米粒子及其负载纤维素酶的表面性质,以傅里叶变换红外光谱分析了固定在MnO2纳米粒子上纤维素酶的官能团性质。纤维素酶在MnO2纳米粒子上最大的固定化效率为75%。考察了固定化纤维素酶的活性、操作pH值、温度、热稳定性和重复使用性等性质。结果表明,所制固定化酶的稳定性比游离酶更高。固定于MnO2纳米粒子上的纤维素酶可用于纤维质类物质的水解反应,且能在较宽的温度和pH值范围内使用。表征结果证实了该催化剂具有非常高的催化纤维素类物质水解的活性。     

The potential in bioethanol production from waste fiber sludges in pulp mill-based biorefineries

Industrial production of bioethanol from fibers that are unusable for pulp production in pulp mills offers an approach to product diversification and more efficient exploitation of the raw material. In an attempt to utilize fibers flowing to the biological waste treatment, selected fiber sludges from three different pulp mills were collected, chemically analyzed, enzymatically hydrolyzed, and fermented for bioethanol production. Another aim was to produce solid residues with higher heat values than those of the original fiber sludges to gain a better fuel for combustion. The glucan content ranged between 32 and 66% of the dry matter. The lignin content varied considerably (1-25%), as did the content of wood extractives (0.2-5.8%). Hydrolysates obtained using enzymatic hydrolysis were found to be readily fermentable using Saccharomyces cerevisiae. Hydrolysis resulted in improved heat values compared with corresponding untreated fiber sludges. Oligomeric xylan fragments in the solid residue obtained after enzymatic hydrolysis were identified using matrix-assisted laser desorption ionization-time of flight and their potential as a new product of a pulp mill-based biorefinery is discussed.     

Brazilian bioethanol program

Brazil is the largest producer of bioethanol, and sugarcane is the main raw material. Bioethanol, is produced by both batch and continuous processes, and in some cases, flocculating yeast is use. This article analyzes the Bracilian Ethanol Program. for the 1996–1997 havest, Brazil produced 14.16 billion L of ethanol and 13.8 million metrict of sugar, from 286 million metrict of sugarcane. These products were produced by 328 industries inactivity, with 101 autonomousethanol plants producing only ethanol, and 227 sugar mills producing sugar and ethanol. The sugar-ethanol market reaches about 7.5 billion US$/yr, accounting for direct and indirect revenues.     

Enhanced enzymatic hydrolysis of poplar bark by combined use of gamma ray and dilute acid for bioethanol production

Pretreatment of poplar bark with a combination of sulfuric acid (3%, w/w, H₂SO₄) and gamma irradiation (0–1000 kGy) was performed in an attempt to enhance enzymatic hydrolysis for bioethanol production. The yields of reducing sugar were slightly increased with an increasing irradiation dose, ranging from 35.4% to 51.5%, with a 56.1% reducing sugar yield observed after dilute acid pretreatment. These results clearly showed that soluble sugars were released faster and to a greater extent in dilute acid-pretreated poplar bark than in gamma irradiation-pretreated bark. When combined pretreatment was carried out, a drastic increase in reducing sugar yield (83.1%) was found compared with individual pretreatment, indicating the possibility of increasing the convertibility of poplar bark following combined pretreatment. These findings are likely associated with cellulose crystallinity, lignin modification, and removal of hemicelluloses.     

Antioxidant Potential and Cytotoxic Effect of Isoflavones Extract from Thai Fermented Soybean (Thua-Nao)

Thua-nao, or Thai fermented soybeans, is a traditional Lanna fermented food in Northern Thailand. It is produced by using a specific bacterial species called Bacillus subtilis var. Thua-nao. We investigated the antioxidant activity and cytotoxic effect of isoflavones from Thua-nao. The phenolic compound contents and total flavonoid contents were determined by spectrophotometry. The antioxidant activity was examined using the ABTS, FRAP, and DPPH assays. The isoflavone contents and phenolic compositions were examined by the high-performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS) techniques. The ability of isoflavones to inhibit human cancer cell growth was assessed by the MTT assay. The total phenolic content, total flavonoid content, and antioxidant activities of the isoflavones were 49.00 ± 0.51 mg GAE/g of dry extract (DE), 10.76 ± 0.82 mg QE/g of DE, 61.03 ± 0.97 µmol Trolox/g of DE, 66.54 ± 3.97 µM FeSO₄/g of DE, and 22.47 ± 1.92% of DPPH inhibition, respectively. Additionally, the isoflavone extracts from Thua-nao had high isoflavone contents and polyphenolic compound compositions, especially daidzein and genistein. The isoflavone demonstrated a weak inhibition of MCF-7 and HEK293 cancer cell growth. It has a high antioxidant component, which is beneficial and can be developed for new therapeutic uses. However, further studies on the benefits of Thua-nao should be performed for realizing better and more effective uses soon.     

Thermogravimetric analysis of forest understory grasses

Forest understory grasses are of significance in the initiation, establishment and maintenance of fire, whether used as a management tool or when occurring as wildfire. The fundamental thermal properties of such grasses are critical to their behavior in fire situations and have been investigated in the current work by the application of thermogravimetric analysis (TGA). TGA was performed in nitrogen and air, over a range of heating rates, allowing for the determination of activation energies and temperatures associated with the degradation of hemicelluloses and cellulose. Of particular interest is the behavior of Imperata cylindrica (cogongrass) an invasive species in the southern United States, which has been found to result in elevated temperatures during fires in forested ecosystems. The results from TGA for this species are in accord with these observations from the field.     

Towards a green bulk-scale biobutanol from bioethanol upgrading

Biobutanol is attracting increasingly interest as a source of renewable energy and biofuels because of its many advantages over bioethanol that include higher energy density, fuel efficiency, and reduced engine damages. Currently, there is a growing interest in producing biobutanol from bioethanol, in view of the tremendous potential benefits of this transformation for the bulk production of biobutanol in a target specific manner. This perspective paper describes recent progress for the ethanol to butanol process. The different catalysts, including homogeneous and heterogeneous catalytic systems, for ethanol to butanol are outlined and compared, and the key issues and requirements for future developments are highlighted.A major challenge for further development and application of ethanol to butanol process is to find an optimal balance between different catalytic functions and to suppress the formation of side products that has plagued most catalytic bioethanol upgrading systems.     

Potential of using a single fermenter for biomass build-up,starch hydrolysis,and ethanol production

Data on conversion of starch on biomass and ethanol bySchwanniomyces castellii in an aerobic-anaerobic solid state fermentation is reported.Schwanniomyces castellii grew exponentially in the aerobic phase (12 h) and simultaneously hydrolyzed nearly half (55%) of the starch initially present. The accumulation of glucose increased up to 12 h, whereas maltose was nearly absent beyond 7 h. Shift of metabolism from oxidative to fermentative pattern was observed about 10 h as a result of the build-up of CO₂ level and faster utilization of O₂. The ethanol production in the anaerobic phase reached the level of 89.3 mg ethanol/g initial dry matter by the end of 30 h. A total of 92.9% of the starch is utilized during the fermentation. The overall ethanol conversion yields are 57.8% of the theoretical value, whereas in the anaerobic phase it was found to be 94.4%. The cell shape, its morphology, and the type of attachment to the solid support were found to be similar in aerobic and anaerobic phases of fermentation. Data given in this work indicate the feasibility of using one single fermenter for aerobic growth to generate inoculum as well as to simultaneously hydrolyze the starch and subsequent anaerobic fermentation to produce ethanol.     

pH and electrolytic conductivity as parameters to characterize bioethanol

To guarantee the quality of bioethanol and avoid damage to the fuel system in a car, the determination of acidity, water content, as well as chloride, sulfate, alkali metal and alkaline earth metal content are important. Electrochemical quantities like pH and electrolytic conductivity are frequently used in biofuel analysis as sum parameters mainly to indicate the risk of corrosion. Many standards and measurement methods used today in the analysis of biofuel are adopted from specifications and test methods originally developed for fossil-based fuels and commercial alcohol. This results from the rapid expansion of the biofuel production. There are efforts to solve remaining metrological and regulatory issues on a regional and international basis on a short term. In the following an overview on the fundamentals for the measurement of pH in bioethanol blends is given. It will be discussed if the electrolytic conductivity of the bioethanol could be a reliable measure of corrosion causing ionic contaminations in biofuel. State of the art, limitations and future tasks for metrology will be discussed.     

The synthesis and characterisation of masked phosphonioalkyl selenoates: Potential ligands for the production of functionalised gold nanoparticles

Two new masked phosphonioalkylselenoate ligands, bis(3-triphenylphosphoniopropyl)diselenide- and 6-(selenocyano)hexyl-triphenylphosphonium-selenocyanates, have been prepared. The molecular structure of the bis(3-triphenylphosphoniopropyl)diselenide diselenocyanate has been determined by X-ray crystallography. The structure reveals an overall stoichiometry of {[Ph₃P⁺(CH₂)₃Se]₂(SeCN⁻)₂ · KOH}, with the bis(3-triphenylphosphoniopropylselenium)diselenocyanate units arranged in pairs around an inversion centre. The potassium ion is disordered over several positions but its main component forms a near linear K?Se contact to one of the selenium atoms in the diselenide bond. The hexyl derivative, 6-(selenocyano)hexyl-triphenylphosphonium selenocyanate forms as a yellow oil that was characterised spectroscopically. Both phosphonioalkylselenide cations undergo reductive cleavage to form phosphonioalkylselenoate zwitterions. Attempts to prepare phosphonioalkylselenoate-functionalised gold nanoparticles in situ through the NaBH₄-promoted reduction of tetrachloroaurate salts in a water/dichloromethane biphasic system are also described.     

Lignocellulosic biomass for bioethanol: Recent advances,technology trends,and barriers to industrial development

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Potential use of gamma irradiation in the production of mussel and oyster reference materials for paralytic shellfish poisoning toxins

Bivalve shellfish samples containing paralytic shellfish poisoning toxins were subjected to gamma irradiation dosage trials in order to assess the potential suitability of the technique in the production of toxin reference materials. Two candidate reference materials of tissue homogenates, mussels (Mytilus sp.) and native oysters (Ostrea edulis), were prepared in-house. Both were subjected to gamma irradiation at four different dose levels, 3.0, 6.0, 13.0 and 18.1 kGy. Bacterial levels were shown to be eliminated in the mussels and significantly reduced in the oysters following irradiation at all four dose levels. Paralytic shellfish poisoning (PSP) toxin concentrations were not significantly reduced in any of the samples indicating the treatment had no adverse affect on the initial stability of any of the PSP toxins monitored. Chromatographic results showed near-identical profiles for treated and non-treated samples inferring that no fluorescent toxin degradation products or matrix interferences were produced during the irradiation process. Results therefore proved that gamma irradiation treatment reduced bacterial levels within paralytic shellfish poisoning reference materials without compromising analyte content, with the subsequent potential to enhance the stability of future candidate reference materials treated in this manner.