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Intensive poultry production generates over 100,000 t of litter annually in West Virginia and 9 × 10^6 t nationwide. Current available technological alternatives based on thermophilic anaerobic digestion for residuals treatment are diverse. A modification of the typical continuous stirred tank reactor is a promising process being relatively stable and owing to its capability to manage considerable amounts of residuals at low operational cost. A 40-m^3 pilot plant digester was used for performance evaluation considering energy input and methane production. Results suggest some changes to the pilot plant configuration are necessary to reduce power consumption although maximizing biodigester performance.

In this present article, genetic algorithms and multilayer perceptron neural network (MLPNN) have been integrated in order to reduce the complexity of an optimization problem. A data-driven identification method based on MLPNN and optimal design of experiments is described in detail. The non-linear model of an extractive ethanol process, represented by a MLPNN, is optimized using real-coded and binary-coded genetic algorithms to determine the optimal operational conditions. In order to check the validity of the computational modeling, the results were compared with the optimization of a deterministic model, whose kinetic parameters were experimentally determined as functions of the temperature.

The separation of lactic acid from lactose in the ultrafiltration permeate of cheese whey broth was studied using a cross-flow nanofiltration membrane unit. Experiments to test lactic acid recovery were conducted at three levels of pressure (1.4, 2.1, and 2.8 MPa), two levels of initial lactic acid concentration (18.6 and 27 g/L), and two types of nanofiltration membranes (DS-5DK and DS-5HL). Higher pressure caused significantly higher permeate flux and higher lactose and lactic acid retention ( p < 0.0001). Higher initial lactic acid concentrations also caused significantly higher permeate flux, but significantly lower lactose and lactic acid retention ( p < 0.0001). The two tested membranes demonstrated significant differences on the permeate flux and lactose and lactic acid retention. Membrane DS-5DK was found to retain 100% of lactose at an initial lactic acid concentration of 18.6 g/L for all the tested pressures, and had a retention level of 99.5% of lactose at initial lactic acid concentration of 27 g/L when the pressure reached 2.8 MPa. For all the tests when lactose retention reached 99–100%, as much as 64% of the lactic acid could be recovered in the permeate.

Countercurrent fermentation of rice straw and chicken manure to carboxylic acids was performed using a mixed culture of marine mesophilic microorganisms. To increase the digestibility of the biomass, rice straw, and chicken manure were pretreated with 0.1 g Ca(OH)_2/g biomass. Fermentation was performed for 80% rice straw and 20% chicken manure at various volatile solid loading rates (VSLR) and liquid residence times (LRT). The highest acid productivity of 1.69 g/(L·d) occurred at a total acid concentration of 32.4 g/L. The highest conversion (0.69 g VS digested/g VS fed) and yield (0.29 g total acids/g VS fed) were at a total acid concentration of 25 g/L. A Continuum Particle Distribution Model of the process predicted the experimental total acid concentration and conversion results with an average error of 6.41% and 6.15%, respectively. Results show how total acid concentrations, conversions, and yields vary with VSLR and LRT in the MixAlco process.

Polyhydroxyalkanoates (PHAs) are polyesters of hydroxyalkanoates synthesized by numerous bacteria as intracellular carbon and energy storage compounds and accumulated as granules in the cytoplasm of cells. In this work, we constructed two recombinant plasmids, pBE2C1 and pBE2C1AB, containing one or two PHA synthse genes, respectively. The two plasmids were inserted into Bacillus subtilis DB104 to generate modified strains, B. subtilis /pBE2C1 and B. subtilis /pBE2C1AB. The two recombinants strains were subjected to fermentation and showed PHA accumulation, the first reported example of mcl-PHA production in B. subtilis . Gas Chromatography analysis identified the compound produced by B. subtilis /pBE2C1 to be a hydroxydecanoate-co-hydroxydodecanoate (HD-co-HDD) polymer whereas that produced by B. subtilis /pBE2C1AB was a hydroxybutyrate-co-hydroxydecanoate-co-hydroxydodecanoate (HB-HD-HDD) polymer.

The use of microorganisms for biotransformations of monoterpenes has stimulated the biotechnological market. Aiming at the highest efficiency in the process of strains screening, the application of molecular biology techniques have been proposed. Based on these aspects, the objective of this work was to select different strains able to convert limonene using fermentative process and random amplified polymorphic DNA (RAPD) markers. The results obtained in the fermentative screening, from 17 strains tested, pointed out that four microorganisms were able to convert limonene into oxygenated derivatives. The RAPD study showed a polymorphism of 96.02% and a similarity from 16.02 to 51.51%. Based on this it was possible to observe a high genetic diversity, even among strains of same species, concluding that the RAPD was not able to correlate the genetic characteristics of the microorganism with the results obtained from the biotransformation process.

Proteases constitute one of the most important groups of industrial enzymes, accounting for at least 25% of the total enzyme sales, with two-thirds of the proteases produced commercially being of microbial origin ( 1 ). Immobilized enzymes are currently the subject of considerable interest because of their advantages over soluble enzymes or alternative technologies, and the steadily increasing number of applications for immobilized enzymes. The general application of immobilized proteins and enzymes has played a central role in the expansion of biotechnology and synthesis-related industries. Proteases have been immobilized on natural and synthetic supports ( 2 , 3 ). In the present work, a protease from Bacillus polymyxa was partially purified with 80% ammonium sulfate precipitation followed by dialysis and chromatography using a diethylaminoethyl (DEAE)-cellulose ion exchange column. Immobilizaiton was evaluated by using different adsorbents (chitin, chitosan, alginate, synthetic zeolite, and raw zeolite) and the storage stability and recycle of the immobilized protease determined. Immobilization yields were estimated to be 96% and 7.5%, by using alginate and chitosan, respectively, after 24 h. The yield of the immobilization was 17% for alginate at 16 h and the enzyme did not adsorb on the chitin, chitosan, synthetic zeolite, and raw zeolite.

In this work, a simulation procedure of a supercritical extraction process was developed through the use of the commercial simulator HYSYS™ (Hyprotech Ltd.), adapting the existing units to the operating conditions typical of the supercritical extraction process. The objective is to recover provitamin A (β-carotene) from palm oil (esterified) using carbon dioxide/ethanol as the supercritical mixed solvent. This example characterizes the problem for recovering high added value product from natural sources, as the palm oil, which is desired by the market. Owing to the fact that esterified palm oil is a complex mixture, made by several components, in order to characterize this system in the simulator, it was necessary to create hypothetical components using the UNIFAC (universal function-group activity coefficients model) group contribution, because they are not present in a conventional database and, then, their physical properties must be estimated and/or predicted before the simulation. The optimization was carried out in each simulation for each equipment, in terms of operating conditions (temperature and pressure), in order to obtain the maximum recovery of carotenes. According to the results, it was possible to concentrate carotenes through two cycles of supercritical extraction with high yield. Furthermore, ethyl esters (biodiesel) were also obtained, as a byproduct of the proposed process, which can also be used as an alternative fuel, with the important characteristic that it is renewable.

Cellulase could not be selectively collected from fermentation broth by simple foam fractionation, because of the presence of other more surface-active compounds. A new approach of affinity foam fractionation was investigated for improvement. A hardwood hydrolysate (containing cellulose oligomers, substrates to cellulase) and two substrate analogs, i.e., carboxymethyl cellulose (CMC) and xylan hydrolysate, were added before the foaming process. The substrates and substrate analogs were indeed found to bind the cellulase selectively and form more hydrophobic complexes that partition more readily onto bubble surfaces. In this study, the effects of the type and concentration of substrate/analog as well as the presence of cells at different growth stages were examined. The foam fractionation properties evaluated included foaming speed, foam stability, foamate volume, and enrichment of filter paper unit (FPU) and individual cellulase components (i.e., endoglucanases, exoglucanases, and β-glucosidases). Depending on the broth and substrate/analog employed, the foamate FPU could be more than fourfold higher than the starting broth FPU. Addition of substrate/analog also deterred the enrichment of other extracellular proteins, resulting in the desired cellulase purification in the foamate. The value of E/P (enzyme activity-FPU/g/L of proteins) in the foamate reached as high as 18, from a lactose-based fermentation broth with original E/P of 5.6. Among cellulase components, exoglucanases were enriched the most and β-glucosidases the least. The study with CMC of different molecular weights (MW) and degrees of substitution (DS) indicated that the CMC with low DS and high MW performed better in cellulase foam fractionation.

Molecular distillation was studied for the separation of tocopherols from soya sludge, both experimentally and by simulation, under different operating conditions, with good agreement. Evaporator temperatures varied from 100°C to 160°C and feed flow rates ranged from 0.1 to 0.8 kg/h. The process pressure was maintained at 10^−6 bar, the feed temperature at 50°C, the condenser temperature at 60°C, and the stirring at 350 rpm. For each process condition, samples of both streams (distillate and residue) were collected and stored at −18°C before tocopherols analyses. Owing to the differences between molecular weights and vapor pressures of free fatty acids and tocopherols, tocopherols preferentially remained in the residue at evaporator temperatures of 100°C and 120°C, whereas for higher temperatures (140°C and 160°C) and lower feed flow rate, tocopherols tended to migrate to the distillate stream.