Understanding Social–Ecological Systems using Loop Analysis

The sustainable management of social–ecological systems (SESs) requires that we understand the complex structure of relationships and feedbacks among ecosystem components and socioeconomic entities. Therefore, the construction and analysis of models integrating ecological and human actors is crucial for describing the functioning of SESs, and qualitative modeling represents an ideal tool since it allows studying dependencies among variables of diverse types. In particular, the qualitative technique of loop analysis yields predictions about how a system’s variables respond to stress factors. Different interaction types, scarce information about functional relationships among variables, and uncertainties in the values of the parameters are the rule rather than exceptions when studying SESs. Accordingly, loop analysis seems to be perfectly suitable to investigate them. Here, we introduce the key aspects of loop analysis, discuss its applications to SESs, and suggest it enables making the first steps toward the integration of the three dimensions of sustainability

Development and characterization of an environmentallyfriendly process sequence (autohydrolysis and organosolv) for wheat straw delignification

The present work describes the delignification of wheat straw through an environmentally friendly process resulting from sequential application of autohydrolysis and organosolv processes. Wheat straw autohydrolysis was performed at 180°C during 30 min with a liquid–solid ratio of 10 (v/w); under these conditions, a solubilization of 44% of the original xylan, with 78% of sugars as xylooligosaccharides of the sum of sugars solubilized in the autohydrolysis liquors generated by the hemicellulose fraction hydrolysis. The corresponding solid fraction enrichment with 63.7% of glucan and 7.55% of residual xylan was treated with a 40% ethanol and 0.1% NaOH aqueous solution at a liquid–solid ratio of 10 (v/w), with the best results obtained at 180°C during 20 min. The highest lignin recovery, measured by acid precipitation of the extracted lignin, was 3.25 g/100 ml. The lignin obtained by precipitation was characterized by FTIR, and the crystallinity indexes from the native cellulose, the cellulose recovered after autohydrolysis, and the cellulose obtained after applying the organosolv process were obtained by X-ray diffraction, returning values of 21.32%, 55.17%, and 53.59%, respectively. Visualization of the fibers was done for all the processing steps using scanning electron microscopy.The authors thank Professor Juan Carlos Parajo from University of Vigo, for the assistance in the materials preparation under autohydrolysis process as well as the ALBAN program for the PhD fellowship support

Processing of byproducts to improve nisin production by Lactococcus lactis

In the last years, disposal from dairy industries have received a special attention due its polluting power in the environment. For this reason, studies have obtained a positive support to develop different alternatives to recycle milk whey components. One of them is its utilization as culture media, aiming to produce biomolecules with noble applications. Nisin is an extracellular peptide, produced by Lactococcus lactis, this peptide has been applied as a natural additive once it presents broad antibacterial activity. Applications of this bacteriocin include dental care products, pharmaceutical products such as stomach ulcers and colon infection treatment and potential birth control. In batch cultures, L. lactis was performed in two different groups of assays. The first group milk whey was prepared in distilled water in four different concentrations: 100 g/l (S100); 50 g/l (S50); 30 g/l (S30); 10 g/l (S10). In the second group of assays, two supplements were added in milk whey with concentration 100 g/l (S100): (1) 5 g/l yeast extract (A1); (2) 5 g/l yeast extract and 10 ml (v/v) tomato extract. Nisin activity was assayed through agar diffusion utilizing Lactobacillus sakei. The results show that the utilization of powder milk whey with concentration of 100 g/l can be used as a culture medium with supplementation. This media is favorable to develop L. lactis cells and nisin production, reaching an activity of about 4 logAU. Biological processing of milk byproduct can be considered as one of the profitable utilization alternatives, generating high-value bioproducts and stimulates researches for its use.The authors wish to thank the Brazilian Committees for the Scientific Technology Research (CNPq, FAPESP, CAPES), for financial support and scholarship

Nisin biotechnological production : evaluation and perspectives in the development of new applications

Nisin is a commercially available bacteriocin of the lantibiotic group produced by Lactococcus lactis ATCC 11454. The importance of nisin as an effective preservative is the fact that its spectrum of inhibitory activity includes almost all Gram-positive, Gram-negative and spoilage bacteria. With several favorable characteristics, this compound has been widely used as a natural food biopreservative. On the other hand, biotechnological production of fuel ethanol from different raw materials (sucrose-containing feedstocks - mainly sugar cane, starchy materials and lignocellulosic biomass) has led to the increase in the researches with trends for improving the bio-ethanol production. During these processes of bio-ethanol production antibiotic agents are added to the pre-fermented broth to prevent unwanted microbial growth. Thus, different questions have been made in relation to performance of the application of the nisin as a natural antibiotic to the ethanol production, as well as their beneficial effects about the yield and productivity in this process. However, the solution to this problematic depends firstly on how the development and implementation of technologies based on nisin production will be undertaken. Perspectives towards the development of modern procedures of nisin production are still needed. In this work the main proposal that has been discussed is the applicability of a novel micro-reactor operated under oscillatory flow mixing envisaged for parallel screening and/or development of industrial bioprocesses in the nisin production. For this reason, initially the objective of this study was to investigate the milk whey, a byproduct from dairy industries, in nisin production aiming to evaluate the growth conditions for L. lactis. In batch cultures, L. lactis was performed in raw milk whey and the nisin activity was assayed through agar diffusion utilizing Lactobacillus sakei ATCC 15521. The results showed that milk whey media is propitious to develop L. lactis cells and produce nisin, reaching activity around 105 AU.mL-1. Biological processing of milk sub-products (milk whey) can be considered one of profitable utilization alternatives, generating high-value bioproducts and contributing to decrease rivers disposal. The use of these sub-products as substrate together with further studies related to application of batch or continuous oscillatory flow reactor would take the more efficient nisin production and finally to a possibility of its evaluation and use in bio-ethanol production.Fundação para a Ciência e a Tecnologia (FCT)FAPESP/BrasilCAPES/Brasi

Hybrid Impedance-Admittance Control for Upper Limb Exoskeleton Using Electromyography

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Xylanase and β‐xylosidase production: alternatives for the autohydrolysis liquor application

Fundação para a Ciência e a Tecnologia (FCT)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP

Production of xylanolytic enzymes by Aspergillus terricola in stirred tank and airlift tower loop bioreactors

Fungi producing high xylanase levels have attracted considerable attention because of their potential industrial applications. Batch cultivations of Aspergillus terricola fungus were evaluated in stirred tank and airlift bioreactors, by using wheat bran particles suspended in the cultivation medium as substrate for xylanase and b-xylosidase production. In the stirred tank bioreactor, in physical conditions of 30°C, 300 rpm, and aeration of 1 vvm (1 l/min), with direct inoculation of fungal spores, 7,475 U/l xylanase was obtained after 36 h of operation, remaining constant after 24 h. In the absence of air injection in the stirred tank reactor, limited xylanase production was observed (final concentration 740 U/l). When the fermentation process was realized in the airlift bioreactor, xylanase production was higher than that observed in the stirred tank bioreactor, being 9,265 U/l at 0.07 vvm (0.4 l/min) and 12,845 U/l at 0.17 vvm (1 l/min) aeration rate.Fundação para a Ciência e a Tecnologia (FCT)CNPq (Brasil)FAPESP (Brasil

A new strategy for xylanase production using wheat straw autohydrolysis liquor as substrate

Agro-industrial residues are lignocellulosic materials with a high content of cellulose, hemicellulose and lignin. If such residues can be produced in bioprocesses (e.g. xylanase production) there is an attractive possibility of their integral use in biotechnological processes. In general, xylanase biosynthesis is induced by its substrate – xylan, but the high xylan content of some wastes such as corn cobs and wheat bran makes them an accessible and cheap source of inducers. Another alternative to improve the xylanase production, which is the main goal of this work, is the treatment of lignocellulosic materials in autohydrolysis processes which, under optimized conditions, lead to the solubilization of hemicelluloses (liquid phase, liquor) that may be favorable to xylanase production. The inclusion of these components in the nutrient medium composition can be a strategy to optimize the microbial xylanase biosynthesis. The best conditions for xylanase production were observed when the microorganism was cultivated in birchwood xylan for 6 days; however, satisfactory results were obtained using a combination of 1% wheat bran with 2% or 10% autohydrolysis liquor, for 5 days fermentation, once the xylanase production was around 86-87% of production with xylan. Besides, the obtained production with 100% wheat straw autohydrolysis liquor was also interesting, once after 7 days of cultivation, the xylanase production was higher than the ones obtained with wheat bran or by the combination of wheat bran and liquor.Biota FAPESP (Brazil)Fundação para a Ciência e a Tecnologia (FCT

Production of xylanases by Aspergillus terricola using wheat bran as carbon source : comparative studies between different bioreactors and influence of aeration and inoculum conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (Biota-FAPESP/Brazil )Fundação para a Ciência e a Tecnologia (FCT