Estudio de las ectomicorrizas en una trufera cultivada situada en Olóriz (Navarra).

En el presente trabajo se aportan los resultados obtenidos en el estudio de las ectomicorrizas presentes en una trufera cultivada situada en Olóriz (Navarra), plantada con árboles (encinas, robles y avellanos) micorrizados por la trufa negra Tuber melanosporum Vitt, a partir de los muéstreos realizados estacionalmente en primavera y otoño durante los años 1996 y 1997. Se han clasificado un total de 7 tipos micorrícicos, en 5 de los cuales se ha identificado el simbionte fúngico a nivel de especie. Se analiza también la evuloción de la micorriza de T. melanosporum, así como las diferencias entre los tres tipos de árboles y la influencia de los tratamientos de acolchado

Self-sufficient flow-biocatalysis by coimmobilization of pyridoxal 5′-phosphate and ω-transaminases onto porous carriers

We expanded the application of self-sufficient heterogeneous biocatalysts containing coimmobilized w-transaminases and pyridoxal 5´-phosphate (PLP) to efficiently operate packed-bed reactors in continuous flow. Using a w-transaminase from Halomonas elongata co-immobilized with PLP onto porous methacrylate-based carriers coated with polyethyleneimine, we operated a packed-bed reactor continuously for up to 50 column volumes at 1.45 mL x min-1 in the enantioselective deamination of model amines (α-methylbenzyl amine), yielding > 90% conversion in all cycles without exogenous addition of cofactor. In this work, we expanded the concept of self-sufficient heterogeneous biocatalysts to other w-transaminases such as the ones from Chromobacterium violaceum and Pseudomonas fluorescens. We found that enzymes with lower affinities towards PLP present lower operational stabilities in flow, even when coimmobilizing PLP. Furthermore, w-transaminases co-immobilized with PLP were successfully implemented for the continuous synthesis of amines and the sustainable metrics were assessed. These results give some clues to exploit PLP-dependent w-transaminases under industrially relevant continuous operations in a more cost-effective and environmentally friendly process

Graphene Materials to Remove Organic Pollutants and Heavy Metals from Water: Photocatalysis and Adsorption

Since graphene was isolated from graphite, different researches have been developed around it. The versatility of graphene properties and their derivates, such as graphene oxide or doped and functionalized graphene materials have expanded the possible applications of these nanostructures. The areas studied of graphene include the following: nanocomposites, drug delivery, transistors, quantum dots, optoelectronic, storage energy, sensors, catalyst support, supercapacitors, among others. However, other important field of these materials is their applications in environment, mainly in the removal of pollutants in water. In this context, there are two possible alternatives to use graphene materials in water purification: photocatalysis and adsorption. In the first case, the key is related to the bandgap and semiconductors properties of these materials, also the versatility of different graphene structures after the oxidation or functionalization, play an important role to get different arrangements useful in photocatalysis and avoid recombination, one of the problems of typical semiconductors photocatalysts. In the second case, surface area and useful chemical groups in carbon material give different options to produce efficient adsorbents depending on different synthesis conditions. Thus, this book chapter covers a review of the photocatalytic activity of graphene materials with emphasis in the removal of organic pollutants and heavy metals from water, in the next topics: graphene-based semiconductor photocatalyst and graphene oxide as photocatalyst. On the other hand, the chapter also discusses the research related to the removal of organic compounds and heavy metals using graphene materials as adsorbents, the topics in this second part are as follows: graphene and graphene oxide as adsorbent of heavy metals from water, graphene, and graphene oxide as adsorbent of organic pollutants from water, functionalized graphene materials as adsorbent of water pollutants, carbon nanomaterials vs. graphene as adsorbents. Therefore, the book chapter presents a review and the discussion of the keys that play an important role in the advances in the research of graphene materials as photocatalysts. In addition, the isotherms and kinetic that produce these materials as adsorbents are also reviewed and discussed, because adsorption process in these materials is important to remove pollutants from water, but also for adsorption is a first step to achieve photocatalyst. The future of this topic in graphene materials is also analyzed

Influence of 1D and 2D carbon fillers and their functionalisation on crystallisation and thermomechanical properties of injection moulded nylon 6,6 nanocomposites

Carbon nanotubes (CNTs) and graphene were used as reinforcing fillers in nylon 6,6 in order to obtain nanocomposites by using an injection moulding process. The two differently structured nanofillers were used in their pristine or reduced form, after oxidation treatment and after amino functionalisation.Three low nanofiller contents were employed. Crystallisation behaviour and perfection of nylon 6,6 crystals were determined by differential scanning calorimetry and wide angle X-ray diffraction, respectively. Crystallinity was slightly enhanced in most samples as the content of the nanofillers was increased. The dimensionality of the materials was found to provide different interfaces and therefore different features in the nylon 6,6 crystal growth resulting in improved crystal perfection. Dynamical, mechanical analysis showed the maximum increases provided by the two nanostructures correspond to the addition of 0.1 wt.% amino functionalised CNTs, enhancing in 30% the storage modulus and the incorporation of 0.5 wt.% of graphene oxide caused an increase of 44% in this property. The latter also provided better thermal stability when compared to pure nylon 6,6 under inert conditions. The superior properties of graphene nanocomposites were attributed to the larger surface area of the two-dimensional graphene compared to the one-dimensional CNTs

Improved Performance of an Epoxy Matrix as a Result of Combining Graphene Oxide and Reduced Graphene

We present an easy and effective way to improve the mechanical properties of an epoxy matrix by reinforcing it with a combination of graphene oxide (GO) and reduced graphene oxide (RGO). These nanocomposites were prepared with different load of nanofillers: 0.1, 0.4, 0.7, 1.0 wt% and a neat epoxy. Ratios of graphene oxide and reduced graphene (GO : RGO) employed were: 0 : 1, 0.25 : 0.75, 0.5 : 0.5, 0.75 : 0.25, and 1 : 0. Results show that with only 0.4 wt% and a ratio 0.2 : 0.75 of GO : RGO, tensile strength and tensile toughness are 52% and 152% higher than neat epoxy while modulus of elasticity was improved ~20%. The obtained results suggest that it is possible achieve advantageous properties by combining graphene in oxidized and reduced conditions as it shows a synergic effect by the presence of both nanofillers

Preliminary study of the mite community structure in different black truffle producing soils

Aims of the study: The goals of this paper are to provide preliminary data on the composition of the mite community in truffle-producing soils (both wild and plantations), and to elucidate those species which may interact with the black truffle life cycle. Area of study: The study was carried out in two black truffle productive zones in Navarra (Spain), in four different plantations and five wild production areas. Material and methods: Fauna was extracted using Berlese Tullgren funnels. Animals were separated into taxonomic groups, and mites were identified. To analyse the composition and community structure of the different habitats, parameters such as abundance, species richness, and Shanon Weiner diversity index (H’) were calculated. Main results: A total of 305 mites were recognized, belonging to 58 species representing the three major taxonomic groups (Oribatida, Prostigmata, Mesostigmata). Research highlights: The results show a possible trend towards wild areas having greater diversity and species richness than plantations. Furthermore, community analysis shows differences in species compositions among different study areas, and oribatid mites always exhibit the highest relative abundance and species richness