Butanol production in a sugarcane biorefinery using ethanol as feedstock. Part I: Integration to a first generation sugarcane distillery

Butanol production from renewable resources has been increasingly investigated over the past decade, mostly for its use as a liquid biofuel for road transportation, since its energy density is higher than that of ethanol and it may be used in gasoline driven engines with practically no changes, but also for use as a feedstock in the chemical industry. Most of the research concerning butanol production focuses on the ABE process (fermentation of sugars into a mixture of acetone, butanol and ethanol), which has several drawbacks regarding microorganism performance and product inhibition. An alternative to ABE fermentation, ethanol catalytic conversion to butanol can produce a higher quality product with less retrofitting than ABE in existing ethanol producing facilities. There are different types of catalysts for the chemical conversion of ethanol to butanol being developed in laboratory scale, but their actual use in a sugarcane processing plant has never before been assessed. Butanol production from ethanol in a sugarcane biorefinery, using data from the literature, was assessed in this study; different technological alternatives (catalytic routes) were evaluated through computer simulation in Aspen Plus (including production of electricity, sugar, ethanol and other products) and economic and environmental impacts were assessed. Results indicate that vapor-phase catalysis presents higher potential for industrial implementation, and commercialization of butanol for use as a chemical feedstock has an economic performance similar to that of current, optimized first generation sugarcane distilleries, but can potentially contribute to cost reduction that will allow commercialization of butanol as a fuel in the future.     

Green Conversion of Agroindustrial Wastes into Chitin and Chitosan by Rhizopus arrhizus and Cunninghamella elegans Strains

This article sets out a method for producing chitin and chitosan by Cunninghamella elegans and Rhizopus arrhizus strains using a green metabolic conversion of agroindustrial wastes (corn steep liquor and molasses). The physicochemical characteristics of the biopolymers and antimicrobial activity are described. Chitin and chitosan were extracted by alkali-acid treatment, and characterized by infrared spectroscopy, viscosity and X-ray diffraction. The effectiveness of chitosan from C. elegans and R. arrhizus in inhibiting the growth of Listeria monocytogenes, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella enterica, Escherichia coli and Yersinia enterocolitica were evaluated by determining the minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC). The highest production of biomass (24.60 g/L), chitin (83.20 mg/g) and chitosan (49.31 mg/g) was obtained by R. arrhizus. Chitin and chitosan from both fungi showed a similar degree of deacetylation, respectively of 25% and 82%, crystallinity indices of 33.80% and 32.80% for chitin, and 20.30% and 17.80% for chitosan. Both chitin and chitosan presented similar viscosimetry of 3.79–3.40 cP and low molecular weight of 5.08 × 10³ and 4.68 × 10³ g/mol. They both showed identical MIC and MBC for all bacteria assayed. These results suggest that: agricultural wastes can be produced in an environmentally friendly way; chitin and chitosan can be produced economically; and that chitosan has antimicrobial potential against pathogenic bacteria.     

Bactericidal and Antioxidant Activity of Essential Oils from <Emphasis Type="Italic">Myristica fragrans</Emphasis> Houtt and <Emphasis Type="Italic">Salvia microphylla</Emphasis> H.B.K

This study chemically characterizes and evaluates the bactericidal and antioxidant activities of essential oils from Myristica fragrans and Salvia microphylla. The essential oils were obtained by steam distillation and were subsequently subjected to analysis by GC–MS and GC. The agar diffusion test was employed to evaluate the bactericidal activity, while the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and β-carotene/linoleic acid tests were used to determine the antioxidant activity. Terpin-4-ol (14.95%), sabinene (13.07%) and γ-terpinene (11.22%) were found to be the major constituents in the essential oil of M. fragrans by gas chromatography, whereas (E)-caryophyllene (15.35%), α-eudesmol (14.06%), β-eudesmol (8.74%) and γ-eudesmol (7.64%) were encountered in the essential oil of S. microphylla. Both essential oils showed bactericidal activity, with the essential oil of S. microphylla being more efficient. The antioxidant activity of the essential oils from M. fragrans and S. microphylla were demonstrated by the β-carotene/linoleic acid test, with IC₅₀ 976 and IC₅₀ 770 μg/mL, respectively.     

Seismic evaluation of old masonry buildings. Part I: Method description and application to a case-study

This paper describes a method developed to evaluate the seismic performance of old masonry buildings, which allows identifying the expected structural collapse mechanism of the structure. The collapse mechanism is identified by the accumulation of several damaged structural elements in specific points of the structure. The methodology allows simulating the non-linear behaviour of masonry buildings by making use of an iterative procedure, where the structure is changed at each step according to the cracking, yielding or collapse of structural elements at the previous steps. The method was applied to an old masonry building from the city of Lisbon that includes a three-dimensional timber structure enclosed in masonry walls aimed at providing seismic resistance. Discussion is made regarding the advantages of the iterative procedure for the identification of the expected structural collapse mechanism of old masonry buildings. The method limitations will also be discussed.     

The macrobenthic community along a mercury contamination in a temperate estuarine system (Ria de Aveiro, Portugal)

Mercury is a widely distributed environmental pollutant and a toxic element to all living organisms. This study represents an attempt to evaluate its correlation with the macrobenthic community structure in a temperate estuarine system, the Ria de Aveiro (Portugal). The macrobenthic community structure showed significant differences along the mercury gradient. Overall, the increase of mercury contamination was associated with reduced total abundance, lower species richness, and dominance of tolerant taxa. The polychaetes Hediste diversicolor and Alkmaria romijni, and the isopod Cyathura carinata were associated with high levels of mercury in sediment, while the bivalves Scrobicularia plana, Cerastoderma edule and Abra alba showed higher density in lesser contaminated sites. Furthermore, highly contaminated sites showed substantially lower abundances of surface-deposit feeders and herbivores, and higher abundances of subsurface-deposit feeders and omnivores. Salinity was also a significant factor affecting the community, being responsible for seasonal variations in the macrobenthic assemblages.     

Cooling slope casting to obtain thixotropic feedstock I: observations with a transparent analogue

New Rheocasting (the NRC process) is a recently developed semisolid processing route. There are two versions of this route. In one, molten alloy is poured directly into a tilted mould and through careful temperature control during cooling a spheroidal semisolid microstructure is achieved, before the material in the mould is upended into a shot sleeve and hence forced into a die. Alternatively, the molten alloy is poured onto a cooling slope and thence into a mould before processing. The aim of the work described in this article, and its companion, was to develop understanding of the microstructural development during the initial stages of this process i.e. in the mould before processing and with the cooling slope/mould combination. In this first article, an analogue system based on aqueous ammonium chloride has been used to visualise what happens when an alloy is poured into a tilted mould with a chill wall. In the companion article, the results for pouring A356 aluminium alloy directly into a mould, and also via a cooling slope into a mould are presented.     

Production of macroporous resins for heavy‐metal removal. I. Nonfunctionalized polymers

The aim of this work was the synthesis of macroporous resins with large specific surface areas through the use of organic solvents (known as porogens or pore‐forming agents) for applications in hexavalent chromium (Cr⁺⁶) removal operations. The synthesis of these materials by suspension polymerization allowed the generation of macroporous structures. The comonomers 4‐vinylpyridine and divinylbenzene were considered in different ratios. Poly(vinyl alcohol) was used as a suspension agent in a mixture of toluene and hexane. The materials produced were characterized with Fourier transform infrared spectroscopy, elemental analysis, thermogravimetry, nitrogen adsorption, and scanning electron microscopy. The macroporous resin with the largest surface area (130 m²/g) was thermally stable up to 300°C and had a structure that included spherical domains with a mean diameter of 68 μm, uniform porosity, and expected high sorption capability. The sorption properties of the resins were evaluated for applications in water‐treatment operations to eliminate Cr⁺⁶ ions at a pH near 7. The advantages of these materials were their high removal capability, high selectivity, and fast adsorption kinetics at a pH 6.5. An aqueous solution of 4 ppm K₂Cr₂O₇ was used to quantify the Cr⁺⁶ content by ultraviolet–visible spectroscopy. A remarkable sorption level (94%) of chromate ions (Cr⁺⁶) was obtained during a 15‐h period for the resin with the highest pyridine group content. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2008     

Effect of enzymatic aroma release on the volatile compounds of white wines presenting different aroma potentials

Wines from Maria Gomes (Fernão Pires) and Bical varieties were treated with an enzymatic preparation, Lallzyme de Lalvin, with β‐glucosidase, pectinase, arabinosidase and rhamnosidase activity. The reference and enzyme‐treated wines were submitted to a process of continuous liquid–liquid extraction with dichloromethane and analysed by GC‐MS. The volatile contents of the wines were 199 and 188 mg l^?1, respectively, for Maria Gomes and Bical. Both varieties contained aliphatic and aromatic alcohols, terpenoids, esters, aliphatic acids and lactones. Enzymatically treated wines showed an increase of 9% in the total amount of volatile compounds of Maria Gomes, due, mainly, to the increase of geraniol (67%), terpendiols (96%), phenols and aromatic alcohols (26%) and esters (32%). Some of them were within their perception limits and may have a contribution to the floral and fruity notes. Conversely, no significant modifications were introduced by enzymatic treatment in the total amount of volatile compounds of Bical wine. The presence of aromatic alcohols in significant amounts, which may represent an interesting characteristic in Bical wines, was not increased by the treatment used. This study with two white varieties grown in the same Appellation shows that the effectiveness of aroma release by enzymatic treatment, using a broad range of enzymatic activities, is closely dependent on the varietal aroma potential, knowledge of which is a key determinant for full exploitation of wine qualities. Copyright © 2004 Society of Chemical Industry     

Effect of light on the concentration of ethyl carbamate in cachaça stored in glass bottles

This study sought to evaluate the influence of natural light on the concentration of ethyl carbamate (EC) in cachaças aged in wooden barrels and stored in glass bottles for a period of 6 months. The quantification of EC was achieved by HPLC using a fluorescence detector after previous derivation of the samples and standards with 9‐xanthydrol. All of the samples presented an EC concentration below the limit established by Brazilian legislation. The highest concentration found was 79.70 µg L^?1. As for the influence of light and storage period, 70% of the samples exhibited an influence of these parameters. Copyright © 2015 The Institute of Brewing & Distilling