Bioprospecting of endophytic fungi from semidesert candelilla (Euphorbia antisyphilitica Zucc): Potential for extracellular enzyme production.

Endophytic microbial communities colonize plants growing under various abiotic stress conditions. Candelilla (Euphorbia antisyphilitica Zucc.) is a shrub that develops functionally in arid and semi-arid zones of Mexico; these conditions generate an association between the plant and the microorganisms, contributing to the production of enzymes as a defense mechanism for resistance to abiotic stress. The objective of this research was to isolate and identify endophyte fungi of candelilla and bioprospection of these endophytic fungi for enzyme production using candelilla by-products. Fungi were isolated and identified using ITS1/ITS4 sequencing. Their potency index (PI) was evaluated in producing endoglucanase, xylanase, amylase, and laccase. Fermentation was carried out at 30°C for 8 days at 200 rpm, with measurements every 2 days, using candelilla by-products as substrate. All fungi exhibited higher cellulase, amylase, and laccase activities on the 2nd, 6th, and 8th day of fermentation, respectively, of fermentation. The fungus Aspergillus niger ITD-IN4.1 showed the highest amylase activity (246.84 U/mg), the genus Neurospora showed the highest cellulase activity, reaching up to 13.45 FPU/mg, and the strain Neurospora sp. ITD-IN5.2 showed the highest laccase activity (3.46 U/mg). This work provides the first report on the endophytic diversity of E. antisyphilitica and its potential role in enzyme production.

Characterization of mating type on aroma production and metabolic properties wild Kluyveromyces marxianus yeasts.

Kluyveromyces marxianus yeasts represent a valuable industry alternative due to their biotechnological potential to produce aromatic compounds. 2-phenylethanol and 2-phenylethylacetate are significant aromatic compounds widely used in food and cosmetics due to their pleasant odor. Natural obtention of these compounds increases their value, and because of this, bioprocesses such as de novo synthesis has become of great significance. However, the relationship between aromatic compound production and yeast's genetic diversity has yet to be studied. In the present study, the analysis of the genetic diversity in K. marxianus isolated from the natural fermentation of Agave duranguensis for Mezcal elaboration is presented. The results of strains in a haploid and diploid state added to the direct relationship between the mating type locus MAT with metabolic characteristics are studied. Growth rate, assimilate carbohydrates (glucose, lactose, and chicory inulin), and the production of aromatic compounds such as ethyl acetate, isoamyl acetate, isoamyl alcohol, 2-phenylethyl butyrate and phenylethyl propionate and the diversity in terms of the output of 2-phenylethanol and 2-phenylethylacetate by de novo synthesis were determinate, obtaining maximum concentrations of 51.30 and 60.39 mg/L by ITD0049 and ITD 0136 yeasts respectively.

Utilization of Agave durangensis leaves by Bacillus cereus 4N for polyhydroxybutyrate (PHB) biosynthesis.

Lignocellulosic wastes may provide a means to economize polyhydroxybutyrate (PHB) production. This study has proposed the use of Agave durangensis leaves obtained from the artisanal mezcal industry as a novel substrate for this aim. Results revealed an increase in PHB biosynthesis (0.32 g/L) and improvement in %PHB (16.79-19.51%) by Bacillus cereus 4N when A. durangensis leaves used as carbon source were physically pre-treated by ultrasound for 30 min (ADL + US30') and thermally pre-treated (ADL + Q). Chemical analyses and SEM studies revealed compositional and morphological changes when A. durangensis leaves were physically pre-treated. Also, elemental analysis of growth media showed that carbon/nitrogen ratios of 14-21, and low nitrogen, hydrogen, and protein content were well-suited for PHB biosynthesis. Confocal microscopy revealed morphological changes in the bacterial cell and carbonosome structure under the influence of different substrates. Finally, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analyses showed that homopolymeric PHB with a high thermal-resistance (271.94-272.89 °C) was produced. Therefore, the present study demonstrates the potential use of physically pre-treated A. durangensis leaves to produce PHB. These results promote the development of a circular economy in Mexico, where lignocellulosic wastes can be employed to produce value-added biotechnological products.

Efficient recovery of thermostable polyhydroxybutyrate (PHB) by a rapid and solvent-free extraction protocol assisted by ultrasound.

Nowadays, there are great research interest in polyhydroxybutyrate (PHB) recovery protocols that reduce the use of organic solvents and efficiently recover this bacterial biopolymer. The present study reports an extraction protocol assisted by ultrasound, which is a rapid protocol that increases the amount of polymeric matter extracted, reduces the cellular digestion step with sodium hypochlorite and eliminates the use of organic solvents. Likewise, characterization studies by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance spectroscopy (1H NMR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) demonstrated that the biopolymer recovered by this protocol is PHB homopolymer with a major thermal-resistance and crystalline properties. Besides, in this study are reported the thermic and crystalline differences between the PHB obtained from the fermentation of complex carbohydrates (agavins) and simple sugars. The biopolymer obtained by this rapid extraction protocol would be suitable for ecological and biomedical applications, due to the low melting temperature, less than 50% crystallinity, and the lack of lipopolysaccharides. Therefore, this extraction protocol might represent an alternative to the traditional protocol based on NaOCl-chloroform and is part of the green trend to improve the PHB production.

Effect of ultrasound pre-treatment on the physicochemical composition of Agave durangensis leaves and potential enzyme production.

Approximately 1 million tons of agave plants are processed annually by the Mexican tequila and mezcal industry, generating vast amounts of agroindustrial solid waste. This type of lignocellulosic biomass is considered to be agroindustrial residue, which can be used to produce enzymes, giving it added value. However, the structure of lignocellulosic biomass makes it highly recalcitrant, and results in relatively low yield when used in its native form. The aim of this study was to investigate an effective pre-treatment method for the production of commercially important hydrolytic enzymes. In this work, the physical and chemical modification of Agave durangensis leaves was analysed using ultrasound and high temperature as pre-treatments, and production of enzymes was evaluated. The pre-treatments resulted in modification of the lignocellulosic structure and composition; the ultrasound pre-treatment improved the production of inulinase by 4 U/mg and cellulase by 0.297 U/mg, and thermal pre-treatment improved ß-fructofuranosidase by 30 U/mg.

Parásitos patógenos en arena de playa y su relación con condiciones ambientales, en un balneario de Puerto Cabello, Venezuela, 2012-2013 / Pathogens parasites in sand beach and it´s relation to environmental conditions in a beach from Puerto Cabello, Venezuela, 2012-2013

Venezuela, presenta una gran variedad de playas frecuentadas durante todo el año, por lo que legalmente se establece un monitoreo permanente de niveles de contaminación para su clasificación "apta" o no para bañistas. Sin embargo, esto no contempla la evaluación parasitológica en la arena de playa como criterio para la referida clasificación. Por ello, la presencia de sólo una forma parasitaria patógena indica que existe contaminación fecal dado por personas, animales o acúmulo de basura a lo largo del balneario; además de la influencia de las características geográficas y ambientales en el desarrollo de los parásitos. Esta investigación tuvo como objetivo determinar la presencia de formas parasitarias patógenas para el hombre como indicadores de contaminación fecal en un balneario en Puerto Cabello. Se recolectaron 110 muestras de arena durante un año en diferentes puntos geográficos seleccionados intencionalmente abarcando la extensión de la ensenada, registrándose: temporadas pre o post vacacionales, humedad relativa de la arena, punto geográfico de muestreo y estación climática. Se realizaron los métodos de Lavado con solución salina 0,85%, Rugai modificado y Willis. Resultados: 25% de muestras fueron positivas para parásitos patógenos, distribuyéndose: larvas rabditoides (8,33%) y filarioides (2,08%) de Strongyloides spp., huevos (2,08%) y larvas rabditoides (12,49%) de Anquilostomideos, huevo de Toxocara spp. (4,17%) y Ooquiste de Isospora belli (2,08%), poniendo en evidencia la contaminación fecal de origen animal y humano. Se espera que investigaciones como éstas fomenten la elaboración de normativas de control sanitario y programas de evaluación de niveles de contaminación parasitaria en arena de playa.

A large number of beaches in Venezuela are visited throughout the year, and there is a legal system in place whereby these beaches are monitored and classified as suitable or not for bathing. However, the presence of parasites in the sand on the beaches is not evaluated as part of this classification The presence of only one pathogenic parasite on a beach indicates fecal contamination either by humans, animals or the accumulation of trash, in addition to geographical and environmental characteristics which could influence the development of the parasites. The aim of this study was to determine the presence of parasites pathogenic to humans as indicators of fecal contamination on a beach in Puerto Cabello. A total of 110 sand samples were collected over one year at different geographic locations selected to cover the entire bay area. Samples were registered as collected during the pre or post-holiday seasons, and the relative moisture of the sand, geographic location and season were also noted. Parasites were collected by washing with 0.85% saline solution, and tested using the Rugai method modified by Willis. Overall, 25% of samples showed positive for the parasites as follows: Strongyloides spp.: rhabditoid (8.33%) and filarioid (2.08%) larvae, Ancylostoma spp.: eggs (2.08%) and rhabditoid larvae (12.49%), Toxocara spp.: eggs (4.17%) and Isospora belli: oocysts (2.08%), indicating extensive fecal contamination from both human and animal sources. We hope that investigations such as this will lead to the establishment of hygiene standards and programs for monitoring the levels of parasitic contamination on sandy beaches.

Elemental concentrations in different species of seaweeds from Loreto Bay, Baja California Sur, Mexico: implications for the geochemical control of metals in algal tissue.

Concentration levels of 21 elements were analyzed by instrumental neutron activation analysis (Rb, Cs, Ca, Sr, Ba, Sc, Cr, Fe, Co, Ni, Zn, Se, As, Sb, Th, U, Br, Hf, Ta, Zr, and Ag) in seven different seaweed species (Codium cuneatum, Sargassum sinicola, Padina durvillaei, Laurencia johnstonii, L. papillosa, Gracilaria pachidermatica and Hypnea pannosa), collected in a shallow coastal zone from Bahia de Loreto, Baja California Sur, Mexico. Measured concentrations in algal tissue spanned almost eight orders of magnitude (from 2.0 x 10(-3) microg g(-1) for Hf to 1.2 x 10(5) microg g(-1) for Ca). Ca was consistently the most abundant element in all analyzed seaweeds, followed by Fe and Sr. Brown algae showed a tendency to incorporate higher concentrations of elements than red and green algae. Additionally, there were significant linear correlations (P < 0.05 to P < 0.001) between a total of 76 different pairs of elements, some of them (e.g. Rb-Ni, Rb-Ag, Sc Cr, Sc-Fe, Sc Ni, Sc Hf, Cr Fe, Fe Ni, Fe-Hf and Ni-Th) highly correlated (r2 > 0.900). A significant correlation (r2 = 0.701, n = 18, P < 0.001) exists between our measurements in the tissue of algae and their corresponding average elemental concentrations in oceanic water from the North Pacific Ocean. Hence, overall elemental abundance in algal tissue apparently is controlled by the elemental abundance in oceanic water, whereas metabolic processes as well as environmental factors relevant to each region modify the final concentration of a given element in the body of a macroalgae.

[Asteroidea, Echinoidea y Holothuroidea in shallow bottoms of Bahía de Loreto, Baja California Sur, Mexico]. / Asteroidea, Echinoidea y Holothuroidea en fondos someros de la Bahía de Loreto, Baja California Sur, México.

To evaluate echinoderm distribution, abundance and density a double 50 m transect, with a side observation range of 2.5 m was used at each of 11 stations (bimonthly samplings, Aug. 1997-Febr. 1998). In Bahía de Loreto the Phylum Echinodermata consists of 26 taxa. The greatest mean abundance by transect and mean densities in order of importance for Echinoidea were: Echinometra vanbrunti (94.1 +/- 52.9 ind, 0.25 ind/m2), Centrostephanus coronatus (38.15 +/- 9.15 ind, 0.06 ind/m2), Tripneustes depressus (28.68 +/- 6.86 ind, 0.039 ind/m2), Eucidaris thouarsii (10.66 +/- 3.37 ind, 0.025 ind/m2) and Diadema mexicanum (11.75 +/- 4.92 ind, 0.023 ind/m2); for Asteroidea were: Phataria unifascialis, Mithrodia bradleyi and Acanthaster planci. Asteroidea was the dominant class with 12 species, followed by Echinoidea with ten and Holothuroidea was represented by four species.