Degradación de residuos vegetales por Coprinus truncorum usando dos métodos de cultivo / Degradation of plant waste by Coprinus truncorum using 2 culture methods

Degradation of yard wastes by Coprinus truncorum growing in a vertical aereated bioreactor or in flasks was studied. There was a constant decay of reducing sugars in the medium that avoided their accumulation and their possible repression of degradative enzymes. Endoxylanase activity at first showed a similar pattern in both culture conditions, with maximal activity on the 12th day, but flasks maintained a high activity thereafter. Flasks also showed a higher endoglucanase activity with a peak on the 18th day, whereas the maximal value in the bioreactor was reached on the 26th day. No Mn-peroxidase and only low values of laccase activity were found. The measurements of pH and soluble proteins during the incubation period were suitable indicators of the degradation process by C. truncorum.

Efecto de las condiciones de cultivo sobre la actividad ligninolÝtica de Stereum hirsutum / Influence of culture conditions on ligninolytic activity of Stereum hirsutum

Stereum hirsutum BAFC 2234 was tested for growth kinetics and ligninolytic enzyme production. The strain showed weak coincidences with widely studied organisms (Phanerochaete chrysosporium, Pleurotus ostreatus) when the response to nitrogen sources was assayed. This could be interpreted as a different regulation to nitrogen metabolism for S. hirsutum BAFC 2234. Alternative carbon sources and the addition of veratryl alcohol and wood extracts were also tested showing partial correspondence with other ligninolytic fungi. On the basis of the high enzymatic activities observed, S. hirsutum BAFC 2234 could be a suitable source of lignin degrading system aiming techological processes.

Evaluación de la capacidad celulolítica de Ascobolus furfuraceus (Fungi, Ascomycotina) / [Evaluation of the cellulolytic capacity of Ascobolus furfuraceus (Fungi, Ascomycotina)]

Growth kinetic variables (dry weight, mycelial protein, extracellular protein and pH evolution) were measured in Ascobolus furfuraceus cultures either with soluble cellulose (CMC) or crystalline cellulose as only carbon sources. When growing on CMC the mycelial protein production reached a maximum at 14 days, while the extracellular protein was maximal at 17 days. On crystalline cellulose more delay was observed (4 and 14 days, respectively). Straight lineal correspondence (r = 0.9883) was observed between the extracellular protein production and enzymatic activity kinetics, showing parallel behavior of these variables. When the biomass and extracellular protein production rates were analysed, the maxima were observed at diverse growth stages. For CMC, the dry weight production rythm precedes the cellulolytic system liberation rythm (maxima at 9 and 14 days, respectively). When crystalline cellulose was the substrate, the maximal rates were inverse, 16th day for biomass production rythm and 12th day for enzyme release rythm. On the basis of such tests and analyses, a model to explain cellulose degration by A. furfuraceus, is proposed.

Efecto de la administración de aceite de maíz sobre la composición en ácidos grasos de los fosfolípidos del plasma de lactantes normales y desnutridos alimentados con leche de vaca / Effect of the administration of corn oil on the composition of fatty acids of plasma phospholipids in normal and malnutrition infants fed with cow's milk

Se estudió el efecto de la administración de aceite de maíz con la dieta sobre el metabolismo de los ácidos grasos esenciales (AGE) en lactantes normales y desnutridos alimentados solamente con leche de vaca desde el nacimiento. Se seleccionó también un grupo de lactantes alimentados con leche materna. Se usó como parámetro bioquímico para evaluar las condiciones en que se encontraban los AGE la composición en ácidos grasos de los fosfolípidos del plasma. Se observó un cuadro consistente con una carencia en AGE tanto en lactantes normales como desnutridos alimentados con leche de vaca, es decir, una disminución de la proporción de los ácidos grasos de la serie n6 y un aumento de los ácidos grasos saturados. Calculando la relación precursor-productos de los ácidos polietilénicos se observó una alteración del metabolismo del ácido linoleico. La administración del aceite de maíz restauró el perfil de los ácidos grasos a valores normales aun en los lactantes desnutridos a pesar de que el síndrome clínico de la desnutrición no había sido corregido

Ensayos de nutrición en Ascobolus furfuraceus. Fuentes de nitrógeno / [Assays of nutrition in Ascobolus furfuraceus. Sources of nitrogen]

The effect of various nitrogen sources on growth and efficiency parameters of Ascobolus furfuraceus was investigated. As nitrogen sources, sodium nitrate and nitrite, inorganic ammonium salts and nitrated organic compounds have been used. The results showed that all of them could be used by the fungus, with the exceptions of sodium nitrite and ammonium oxalate. Good correlation was observed among the growth parameters, the ’economic coefficients’ of uptake and internal conversion of sources, and the specific respiration rates. The best nitrogen source - estimated as growth and efficiency parameters - was ammonium carbonate in the culture conditions used. The possibility of heterotrophic carbon fixation is discussed.

Cinetica de incorporacion de glucosa y variacion morfologica del micelio de Ascobolus furfuraceus. / Kinetics of glucose uptake and morphological changes of the mycelium of Ascobulus furfuraceus

La cinetica de incorporacion de glucosa por el micelio de Ascobolus furfuraceus de 13 dias de crecimiento y realimentado con glucosa o con medio fresco total, esta en correlacion con la diferenciacion progresiva de estructuras vesiculares que funcionarian como reservorio de glucogeno