Ethanol Production from the Organic Fraction Obtained After Thermal Pretreatment of Municipal Solid Waste

In this work, the use of organic fraction from municipal solid waste (MSW) as substrate for ethanol production based on enzymatic hydrolysis was evaluated. MSW was subjected to a thermal pretreatment (active hygienization) at 160?°C from 5 to 50 min. The organic fiber obtained after 30 min was used as substrate in a simultaneous saccharification and fermentation (SSF) and fed-batch SSF process using cellulases and amylases. In a fed-batch mode with 25% (w/w) substrate loading, final ethanol concentration of 30 g/L was achieved (60% of theoretical). In these conditions, more than 160 L of ethanol per ton of dry matter could be produced from the organic fraction of MSW.     

Application of fentonś reaction to steam explosion prehydrolysates from poplar biomass

The application of Fenton’s reaction to enhance the fermentability of prehydrolysates obtained from steam explosion pretreatment of poplar biomass was studied. Reaction conditions of temperature and H₂O₂ and Fe(II) concentrations were studied. The fermentability of prehydrolysate treated by Fenton’s reaction was tested by using different inoculum sizes of thermotolerant strain Kluyveromyces marxianus CECT 10875. The highest percentages of toxic compound degradation (ranging from 71 to 93% removal) were obtained at the highest H₂O₂ concentration tested (50 mM). However, a negative effect on fermentability was observed at this H₂O₂ concentration at the lower inoculum loading. An increase in inoculum size to 0.6 g/L resulted in an enhanced ethanol fermentation yield of 95% relative to control.     

Comparison of the C1‐symmetric diastereoisomers of a zirconocene‐based catalyst in ethylene polymerization: A benzyl substituent as a regulator in branch formation

C₁‐symmetric diastereoisomers of a zirconocene dichloride, SiMe₂(3‐benzylindenyl)(indenyl)ZrCl₂, known as catalyst precursors used to produce polypropylenes with similar molecular weights and tacticities, have been investigated in ethylene polymerization. Activated by methylaluminoxane, they produce microstructurally different polymers: high‐density polyethylene and linear low‐density polyethylene, the latter characterized by the presence of ethyl branches. The formation of branches is relevant in the complex having a sterically more crowded (inward) site. A comparison with the complex without substituents, meso‐SiMe₂(indenyl)₂ZrCl₂, shows that the presence of a benzyl group on only one of the two indenyl moieties can regulate the number of branches and the molecular weight of the macromolecule. Actually, the unsubstituted complex is able to give double the number of branches and lower molecular weights, whereas the C₁‐symmetric disubstituted complexes previously reported generally give linear polyethylene. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3551–3555, 2006     

A New Application of Dimethyl Trithiocarbonate. Methylthiothiocarbonylation of 2,4-Pentanedione and Some β-Oxoesters

2,4-Pentanedione, ethyl acetoacetate, benzoyl acetate and diethyl malonate 1a-d react with sodium acetate and dimethyl trithiocarbonate in dimethylformamide to afford methyl-β,β′-dicarbonyldithiocarboxylate derivatives 2a-d in moderate yield.     

The Synthesis of 4-Alkyldithioate-5-hydroxy-3-methyl-1-phenylpyrazoles

The title pyrazoles (2)-(8) were obtained by the condensation of 3-methyl-1-phenyl-2-pyrazoline-5-one (1) with carbon disulfide and primary alkyl halides, in the presence of n-butyllithium.     

The effect of the alkyl chain length on the mesomorphic properties of new lactic acid derivatives

New series of lactic acid derivatives with alkyl terminal chain have been synthesised and their mesomorphic properties studied. We have varied the length of chiral and non-chiral terminal alkyl chains and found that prolonging both chains has a strong effect on the SmA*–SmC* phase transition. Most of the new materials exhibit only paraelectric SmA* phase; for homologues with a longer non-chiral chain (m ≥ 10), the ferroelectric (SmC*) phase appears below the SmA* on cooling and persists down to a room temperature. The role of the chiral terminal chain in the molecule is quite opposite – only its short length supports the existence of ferroelectric phase. Additionally, a hexatic phase appeared below the SmA*–SmC* phase sequence for several homologues at low temperatures. All materials have been studied using standard experimental techniques (differential scanning calorimetry (DSC), texture observations, polarisation and tilt angle measurements, etc.). Liquid crystalline properties of new materials have been compared with the previously prepared and studied lactic acid derivatives.     

Luminescence-Based Optical Fiber Chemical Sensors

A scheme for the simultaneous determination of temperature and analyte concentration for application in luminescence-based chemical sensors is proposed. This scheme is applied to an optical oxygen sensor, which is based on the quenching of the fluorescence of a ruthenium complex. Temperature measurement is performed using the excitation radiation and an absorption long-pass filter. Preliminary results are presented that show the viability of an oxygen measurement that is independent of temperature and optical power level. The possibility of self-referenced temperature measurements with semiconductor nanoparticles is also investigated. In order to optimize the sensor design, several different optical fiber probe geometries for oxygen sensing are tested and compared, including different methods of coupling radiation into the optical fiber system. Polyvinyl alcohol (PVA) and polyacrylamide membranes are tested as supports for sensor immobilization in fiber-optical pH sensing devices in aqueous solution. Some results are presented that show the feasibility of using fiber-optical pH indicators for remote monitoring.     

Remodeling of the Fibrillation Pathway of α-Synuclein by Interaction with Antimicrobial Peptide LL-III

Liquid-liquid phase separation (LLPS) has emerged as a key mechanism for intracellular organization, and many recent studies have provided important insights into the role of LLPS in cell biology. There is also evidence that LLPS is associated with a variety of medical conditions, including neurodegenerative disorders. Pathological aggregation of α-synuclein, which is causally linked to Parkinson's disease, can proceed via droplet condensation, which then gradually transitions to the amyloid state. We show that the antimicrobial peptide LL-III is able to interact with both monomers and condensates of α-synuclein, leading to stabilization of the droplet and preventing conversion to the fibrillar state. The anti-aggregation activity of LL-III was also confirmed in a cellular model. We anticipate that studying the interaction of antimicrobial-type peptides with liquid condensates such as α-synuclein will contribute to the understanding of disease mechanisms (that arise in such condensates) and may also open up exciting new avenues for intervention.     

Pilot Study on Exhaled Breath Analysis for a Healthy Adult Population in Hawaii

Fast diagnostic results using breath analysis are an anticipated possibility for disease diagnosis or general health screenings. Tests that do not require sending specimens to medical laboratories possess capabilities to speed patient diagnosis and protect both patient and healthcare staff from unnecessary prolonged exposure. The objective of this work was to develop testing procedures on an initial healthy subject cohort in Hawaii to act as a range-finding pilot study for characterizing the baseline of exhaled breath prior to further research. Using comprehensive two-dimensional gas chromatography (GC×GC), this study analyzed exhaled breath from a healthy adult population in Hawaii to profile the range of different volatile organic compounds (VOCs) and survey Hawaii-specific differences. The most consistently reported compounds in the breath profile of individuals were acetic acid, dimethoxymethane, benzoic acid methyl ester, and n-hexane. In comparison to other breathprinting studies, the list of compounds discovered was representative of control cohorts. This must be considered when implementing proposed breath diagnostics in new locations with increased interpersonal variation due to diversity. Further studies on larger numbers of subjects over longer periods of time will provide additional foundational data on baseline breath VOC profiles of control populations for comparison to disease-positive cohorts.     

Inulin-containing biomass for ethanol production

The use of stalks instead of tubers as a source of carbohydrates for ethanol production has been investigated. The inulin present in the stalks of Jerusalem artichoke was extracted with water and the effect of solid-liquid ratio, temperature, and acid addition was studied and optimized in order to attain a high-fructose fermentable extract. The maximum extraction efficiency (corresponding to 35 g/L) of soluble sugars was obtained at 1/6 solidliquid ratio. Fermentations of hydrolyzed extracts by baker's yeast and direct fermentation by an inulinease activity yeast were also performed and the potential to use this feedstock for bioethanol production assessed. The results show that the carbohydrates derived from Jerusalem artichoke stalks can be converted efficiently to ethanol by acidic hydrolysis followed by fermentation with Saccharomyces cerevisiae or by direct fermentation of inulin using Kluyveromyces marxianus strains. In this last case about 30 h to complete fermentation was required in comparison with 8–9 h obtained in experiments with S. cerevisiae growth on acid extracted juices.