Abstract Background: In mezcal industry, Agave salmiana leaves are a crop residue and a potential source of fructans. Agave fructans are a soluble fiber that can act as prebiotic in gut microbiota. Questions and Hypotheses: The molecular weight distribution of agave fructans extracted from leaves of Agave salmiana depends on the region where agaves growth and on the subspecies. Studied species: Agave salmiana Otto ex Salm Dyck, spp. salmiana and Agave salmiana spp. crassispina. Study site: Twelve municipalities from Guanajuato México were sampled: Ocampo, San Felipe, San Diego de la Unión, Victoria, Xichú, Atarjea, Dolores Hidalgo, Doctor Mora, Santa Catarina, Tierra Blanca, San Miguel Allende and Comonfort. Methods: The base of the leaf close to the stem of Agave salmiana ssp. salmiana and A. salmiana ssp. crassispina plants, six years old, were harvested. Water soluble carbohydrates were extracted, the content and molecular weight distribution of fructans was determined by HPLC-SEC. Results: An average of 0.7 % of soluble carbohydrates was recovered from the leaves. The molecular weight distribution of Agave salmiana fructans was: number average molecular weight: 3,209 g/mol; average molecular weight: 5,046 g/mol; number average degree of polymerization: 19; weight average degree of polymerization: 30. High polymerization degree fructans content was greater in Agave salmiana spp. salmiana (55 %) than in Agave salmiana spp. crassispina (47 %). Conclusions: The leaves of Agave salmiana contain a low proportion of high-molecular-weight fructans, compared to commercial agave fructans. The results demonstrated the technical feasibility to obtain fructans from Agave salmiana leaves.

Resumen Antecedentes: Las hojas de Agave salmiana, como residuo de la industria mezclaera, podrían ser fuente de fructanos. Los fructanos de agave son fibras solubles prebióticas. Hipótesis: La distribución de tamaños de fructanos extraídos de hojas de Agave salmiana será distinta en función de la región y de la subespecie. Especies estudiadas: Agave salmiana Otto ex Salm Dyck, spp. salmiana and Agave salmiana spp. crassispina. Lugar de estudio: Doce municipios de Guanajuato: Ocampo, San Felipe, San Diego de la Unión, Victoria, Xichú, Atarjea, Dolores Hidalgo, Doctor Mora, Santa Catarina, Tierra Blanca, San Miguel Allende and Comonfort. Métodos: Se muestreó la base de hojas de Agave salmiana ssp. salmiana y A. salmiana ssp. crassispina de seis años. Se extrajeron los carbohidratos solubles en agua y se determinó contenido y distribución de tamaños de los fructanos por HPLC-SEC. Resultados: Se extrajeron en promedio 0.7 % de carbohidratos solubles. La distribución de tamaños de los fructanos de Agave salmiana fue: peso molecular promedio en número: 3,209 g/mol; peso molecular promedio en masa: 5,046 g/mol; grado de polimerización promedio en número: 19; grado de polimerización promedio en masa: 30. El contenido de fructanos con alto grado de polimerización fue mayor en Agave salmiana spp. salmiana (55 %) que en Agave salmiana spp. crassispina (47 %). Conclusiones: Las hojas de Agave salmiana contienen baja cantidad de fructanos de alto peso molecular comparados con fructanos de agave comerciales. Se demostró la factibilidad técnica de obtener fructanos a partir de hojas de Agave salmiana.

Resumen El presente artículo analiza dos dinámicas clave en las experiencias de vídeo participativo con colectivos indígenas: 1) la autonomía de los grupos participantes, que aparece como el horizonte necesario hacia el que deben caminar estos proyectos para generar la apropiación de la tecnología en sus formas de uso e imprimir un auténtico valor político a las actividades desarrolladas, y 2) la sostenibilidad, que actúa como base material de dicha acción en el tiempo. A través del estudio de La Marabunta Filmadora, el texto examina críticamente desde esta perspectiva aspectos como la relación con los financiadores externos, el papel de la facilitación, la relación con la comunidad o dinámicas de sostenibilidad en este tipo de propuestas.

Abstract The text examines key dynamics underpinning participatory video experiences with indigenous collectivities: (1) Autonomy appears here as a very specific and necessary goal, particularly if these projects aim to achieve empowerment and a real political impact within indigenous communities, and (2) Sustainability represents the material ground in order to maintain these actions over time. Taking La Marabunta Filmadora as a case-study, we analyze aspects such as the role played by external funders, facilitation as a process, community dynamics or how sustainability is achieved in these kind of participatory video experiences.

ABSTRACT To select the best biosurfactant producer, Pseudomonas putida, Bacillus megatherium, Bacillus licheniformis and Bacillus subtilis were cultured in flasks on media with different salinity [low salinity (LS), Bushnell-Haas (BH) and artificial sea water (SW) media] supplemented or not with toluene as a model pollutant. Toluene inhibited the growth of all microorganisms and stimulated the biosurfactant production. B. subtilis exhibited the best performance, being able to lower the surface tension (ST) in the LS medium to 65.5 mN/min in the absence of toluene, and to 46.5 mN/min in the BH medium in the presence of toluene, corresponding to ST reductions of 13.0 and 27.5 mN/m, respectively. Scaling up the process to a bench-scale fermentor, the best results were obtained in the LS medium, where B. subtilis was able to reduce the toluene concentration from 26.0 to 4.3 g/L within 12 h and ST by 17.2 mN/m within 18 h. The results of this study point out that B. subtilis is an interesting biosurfactant producer, which could be used in the bioremediation of toluene-contaminated water.

Valencia orange (Citrus sinensis) peel was employed in this work as raw material for the production of citric acid (CA) by solid-state fermentation (SSF) of Aspergillus niger CECT-2090 (ATCC 9142, NRRL 599) in Erlenmeyer flasks. To investigate the effects of the main operating variables, the inoculum concentration was varied in the range 0.5·10³ to 0.7·10(8) spores/g dry orange peel, the bed loading from 1.0 to 4.8 g of dry orange peel (corresponding to 35-80 % of the total volume), and the moisture content between 50 and 100 % of the maximum water retention capacity (MWRC) of the material. Moreover, additional experiments were done adding methanol or water in different proportions and ways. The optimal conditions for CA production revealed to be an inoculum of 0.5·10(6) spores/g dry orange peel, a bed loading of 1.0 g of dry orange peel, and a humidification pattern of 70 % MWRC at the beginning of the incubation with posterior addition of 0.12 mL H2O/g dry orange peel (corresponding to 3.3 % of the MWRC) every 12 h starting from 62 h. The addition of methanol was detrimental for the CA production. Under these conditions, the SSF ensured an effective specific production of CA (193 mg CA/g dry orange peel), corresponding to yields of product on total initial and consumed sugars (glucose, fructose and sucrose) of 376 and 383 mg CA/g, respectively. These results, which demonstrate the viability of the CA production by SSF from orange peel without addition of other nutrients, could be of interest to possible, future industrial applications.

This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid.

The 'Ibermedia' program, launched in 1997 on the V Cumbre Iberoamericana de Jefes de Estado y de Gobierno, has laid the foundations for future and effective audiovisual collaboration in the region, an effort that could have been much more fruitful had it been designed with better resources and more ambitious aims in mind. Today, a total number of thirteen countries interact through 'Ibermedia', using a multilateral fund scheme in order to promote not only co-productions but also initiatives in sectors such as film distribution, advertising campaigns for concrete films or professional training. This paper will undertake an exhaustive assessment of the program s first functioning years (1998-2007), analysing comments and opinions on 'Ibermedia', as well as making an evaluation of its impact in the region.

Pese a deficiencias en el funcionamiento y a su falta de ambición económica, la creación del programa Ibermedia ha sido un punto de inflexión para crear un espacio audiovisual común para la región iberoamericana. A través de un fondo financiero multilateral, el programa ha intentado estimular la coproducción de productos para el cine y la televisión, el montaje inicial de proyectos cinematográficos, la distribución de películas dentro del mercado regional y la formación de recursos humanos para la industria audiovisual. Realizar una primera evaluación exhaustiva de sus primeros años de funcionamiento (1998-2007), analizar las opiniones que se han vertido sobre el mismo, así como realizar una primera valoración de su impacto en la región es el objetivo central de este trabajo.

A quantitative methodology to determine formation constants that takes into consideration the 27Al-NMR signals of Al(III)-H2O systems has been analyzed, where area fractions beneath the peaks recorded were associated with the corresponding species fractions. The values of the formation constants were compared with the model obtained by potentiometric studies. In agreement with previous reports, the -log*β values obtained by NMR and potentiometry, at 0.020 M ≤ [Al(III)]total ≤ 0.500 M are 12.96 ± 0.02 for Al(OH)3, 13.50±0.02 for Al3(OH)4(5+), and 109.70±0.09 for Al13(OH)32(7+), by assuming that Al(OH)²+ has a value of 5.29. Additionally the equilibrium constant values obtained allowed fitting of the conductimetry titrations in the 6.00(10-³) M ≤ [Al(III)]total ≤ 0.120 M. The algorithm presented in this work gives a support to establish that the area fractions of NMR signals are proportional to the species concentration fractions.

Una metodología para determinar constantes de formación por medio de señales de 27Al-NMR para sistemas Al(III)-H2O se aplicó, en donde las fracciones de área bajo los picos se asoció con las fracciones de las especies correspondientes. Los valores de constantes de formación obtenidos de esta forma se compararon con los obtenidos con estudios potenciométricos. Los valores obtenidos de -log*β obtenidos por NMR y potenciometría a partir de sistemas con 0.020 M ≤ [Al(III)]total ≤ 0.500 M son 12.96 ± 0.02 para Al(OH)3, 13.50 ± 0.02 para Al3(OH)4(5+), y 109.70 ± 0.09 para Al13(OH)32(7+), considerando que Al(OH)2+ tiene un valor de 5.29, y concuerdan con reportes previos. Además, estos valores de constantes de equilibrio permiten ajustar curvas de valoración conductimétricas, en las cuales 6.00(10-³) M ≤ [Al(III)]total ≤ 0.120 M. Este algoritmo da fundamento para establecer que las fracciones de área de las señales de NMR son proporcionales a las fracciones de concentración de las especies.

Lacustrine and fluviolacustrine deposits of the Charo sequence crop out extensively along tens of kilometres, and they overlie the Miocene volcanic sequences of the Mil Cumbres Complex in an E-W oriented basin. Eastwards of Morelia city (central Mexico), layers of non lithified clayey sediments of about 3 m in thickness are overlaid by massive diatomite deposits developed during the Miocene-Pliocene in the Cuitzeo palaeolake. Major outcrops are located south and east of the village of Charo at the Las Pulgas, Lomas Blancas and Tzitzimeo sites; all having similar mineralogical facies and strati graphic correlation. Field studies, petrography and X-ray fluorescence spectrometry (XRF) indicated that the parent rock was mainly of andesitic composition with minor daciticrhyolitic components. The source of the raw material was located in the upper topographic levels of the present horst-graben system. The diagenetic clays were identified as smectites. The central part of the Las Pulgas column shows a beidellite-nontronite (B-N) association. Likewise, 27A1-NMR and Móssbauer spectroscopies confirm the B-N character. Interlaid and overlying diatomite strata indicate a lacustrine environment, favourable to the development of secondary clays. The stability of lacustrine conditions gave place to an incipient stratification (smectite-illite), better developed in the middle part of the clayey levels.

Depósitos lacustres y fluviolacustres de la secuencia de Charo afloran a lo largo de decenas de kilómetros y sobreyacen las secuencias volcanicas del Mioceno del Complejo de Mil Cumbres en una cuenca orientada Este-Oeste. Al oeste de la ciudad de Morelia (centro oeste de Mexico), los estratos arcillosos no litificados con espesores de 3 m son sobreyacidos por depósitos de diatomita masiva que se desarrollaron durante el Mioceno-Plioceno en el paleolago de Cuitzeo. Los mas grandes afloramientos están localizados al sur y este del poblado de Charo en Las Pulgas, Lomas Blancas y Tzitzimeo, todas conformando facies mineralógicas y correlación estratigrqfica similares. Estudios de campo, petrografía y espectrometría de rayos X (XRF) indican que la roca parental fue principalmente de composición andesítica con componentes menores de tipo dacitico y riolítico. La fuente de este material se localiza en los niveles estratigráficos del actual sistema regional de horst y grabens. Las arcillas diagenéticas fueron identificadas como esmectitas. La parte central de la columna de Las Pulgas muestra una asociación de beidellita-nontronita (B-N). Igualmente la 27Al-NMR y la espectrometría Móssbauer confirman el carácter B-N. Las diatomitas intercaladas y que sobreyacen estos depósitos arcillosos indican un ambiente lacustre que favoreció la incipiente estratificación (esmectitaillita), que se desarrolla favorablemente en la parte media de los estratos arcillosos.

Micélios liofilizados de Aspergillus oryzae CBS 10207, A. oryzae MIM, Rhizopus oryzae CBS 11207, R. oryzae CBS 39134, R. oryzae CBS 26028 e R. oryzae CBS 32847 foram testados neste estudo com vista à seleção do melhor biocatalisador para efetuar a acilação de etanol com ácidos fenilacético e 2-fenilpropiônico. As atividades carboxilesterásicas de A. oryzae MIM e R. oryzae 11207, que resultaram ser os melhores biocatalisadores, foram investigadas tanto em tampão fosfato 0,1 M como em n-heptano para catalisar a hidrólise ou a síntese dos ésteres etílicos destes ácidos. A. oryzae pareceu ser mais eficaz que R. oryzae, provavelmente devido a condições micro-ambientais e a um cenário termodinâmico mais favoráveis. Os resultados obtidos em termos de formação do produto e consumo dos substratos em função do tempo foram usados para a estimativa dos rendimentos de conversão máximos, as constantes de equilíbrio e os tempos necessários para alcançar metade da conversão máxima, fornecendo desta forma suficientes informações sobre esses equilíbrios.

To select the best biocatalysts for ethanol acylations with phenylacetic and 2-phenylpropionic acids, lyophilized mycelia of Aspergillus oryzae CBS 10207, A. oryzae MIM, Rhizopus oryzae CBS 11207, R. oryzae CBS 39134, R. oryzae CBS 26028 and R. oryzae CBS 32847 were tested in this study. The carboxylesterase activities of A. oryzae MIM and R. oryzae 11207, which revealed to be the best biocatalysts, were investigated either in 0.1 M phosphate buffer or in n-heptane to catalyze the hydrolysis or the synthesis of ethyl esters of these acids, respectively. A. oryzae proved more effective than R. oryzae, probably due to more favorable microenvironment conditions and thermodynamic scenario. The results in terms of product formation and substrate consumption versus time were used to estimate the maximum conversion yields, the equilibrium constants and the times needed to reach half maximum conversion, thus providing sufficient information about these equilibria.