Poster Session 2017

Poster Session 2017

Redesign of Photo-Bioreactor.  Brian A. Trujillo Talavera and José R. Pérez Jiménez.  ¹School of Engineering, ²School of National Science and Technology, Universidad del Turabo, Gurabo, Puerto Rico, 00778.  Abstract: Algae’s are the underwater form of grass. Same as grass reproduces by photosynthesis, algae’s reproduce equally, therefore algae need light. The objective of this research is to design a photo bioreactor in order to cultivate algae in a laboratory scenario. Using the 3D designer program of SolidWorks we can create a model that better suits our objective and then use a 3D printer to obtain the most accurate precision of the design. A glass bottle will be used to cultivate the algae under study. A plastic (normal filament) rack will be design with dimensions of 10x8x8 inches. Each rack will hold six bottles of different sizes. Malleable plastic skins with LED lights and aluminum tape will cover each bottle. Electric cables will connect bottles with each other. Skin covers will allow each bottle to receive maximum light. A timer will be added to the reactor to allow light and dark cycles during incubation. The design must be cost effective, with safe materials and can place bottles of different sizes that allow up scaling of algae cultures. The end product should be able to be place on a higher bioreactor for industrial purposes. We expect to make a model with reusable plastic, lightweight material and very versatile since the rack can also be use also for other type of cultures without the skin.

Antibiotic Activity by Microbes at the San Juan Bay Estuary System.  Brian Sang-Laboy, Abisrael Morales-Feliciano, and José R. Pérez-Jiménez.  Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: This study analyzed the biodiversity present in the Bay San Juan Estuary is a system of interconnected lagoon and channels that flow into the Bay. Throughout this ecosystem, the water column receives discharges from natural sites, houses, and commercials facilities that have compromised its quality. Thus, the estuarine system harbors challenges among diverse microbes. Our objective is to isolate bacteria from the San Juan Bay Estuary that exhibits antimicrobial activity. Water samples were cultivated in Tryptic Soy Agar plates aiming for dense cultures. Bacterial exhibiting inhibition zones were isolated and characterized according to morphology, selected biochemical tests, and 16S rDNA sequencing. Antimicrobial activity was demonstrated by inhibition zone in concurrent cultivation with reference stains. The collections of forty-nine bacteria were isolated with antimicrobial activity. However, these are halotolerant stains, Gram-positive rods, producing catalase, and unable to reduce nitrate. Most of the antimicrobial activity was detected against Pseudomonas putida, Enterococcus raffinosus, Staphylococcus epidermidis, Bacillus subtilis, and Lysobacter antibioticus. The twenty-six isolated were able to inhibit the growth of four reference stains. Sequencing of the 16S rDNA demonstrated the presence of three Alcaligenes strains, Bacillus sp., Achromobacter sp. and Pseudomonas sp. The 16S rDNA is being sequenced for additional bioprospects. The potential of these microorganisms to produce useful antimicrobial compounds is great and must be better explored.

Growing Botryococcus sp. on Municipal Wastewater from Puerto Rico for Simultaneous Nutrient Removal and Energy Feedstock Production.  Catalina Dávila¹, and Gary Toranzos².  ¹Department of Biology, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778; ²Environmental Microbiology Laboratory, Department of Biology, University of Puerto Rico, Rio Piedras campus, Puerto Rico.  Abstract: Several approaches have been proposed for the biological treatment of wastewaters. Among these, growing algae in wastewater effluents is a promising one, since it represents an alternative for both nutrient load decline and reduction of treatment costs. Furthermore, by simultaneously growing algae and remediating wastewaters it is theoretically possible to produce algal by-products, such as oil, bioplastics and nutraceuticals, in a sustainable way. However, few studies aiming to reduce nutrient load in wastewaters from Puerto Rico have been performed with microalgae and none of them have employed native species. We examined the capability of Botryococcus sp., a newly isolated strain from a brackish water pond in Puerto-Rico, of removing nutrients from urban wastewaters, as well as its performance as a possible biofuel feedstock. Botryococcus sp., was cultured in secondary and tertiary urban wastewater effluents for 18 days under continuous illumination and mechanical stirring. Biomass, lipid content, lipid composition and nutrient removal efficiencies (i.e. N and P) were measured. Results showed overall growth rates of 0.19 and 0.21 in the secondary and tertiary effluents, respectively. Removal rates of NO3-N, NO2-N and PO4-P were estimated at 100%, 90% and 40% in the secondary effluent and 96%, 57% and 98% in the tertiary effluent. NH4–N was totally removed from the secondary effluent during the first three days of the incubation period. A relative lipid content of 70% and 84% was found when culturing Botryococcus sp. in secondary and tertiary effluents, respectively. Results from GC-MS analysis showed a large quantity of long chain fatty acids, mainly palmitic, stearic, oleic and linoleic acids, which resemble fatty acid profiles of plant crops traditionally used as a source of biodiesel, suggesting that this strain could be a good candidate for energy production. Our results reinforced the possibility of using domestic wastewaters to grow Botryococcus sp. for the removal of nutrients while producing oils with energy purposes. Also, results demonstrate that growing microalgae in wastewater could be a more efficient process for nutrient removal than other biological approaches.

Saccharomyces cerevisiae as a biosensor to study chemical mixtures and AHR signaling.  Chris A Muriel Mundo¹, Emmanuel Vázquez-Rivera², and Christopher A. Bradfield².  ¹Universidad Del Este, Carolina, PR; ²Molecular and Environmental Toxicology Center, University of Wisconsin-Madison.  Abstract: The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor and member of the Basic-Helix-Loop-Helix-Per-Arnt- Sim (bHLH-PAS) gene superfamily. It is best known for its binding affinity for many environmental pollutants such as the polycyclic aromatic hydrocarbon (PAHs) and the halogenated aromatic hydrocarbon (HAHs) like 2,3,7,8 tetrachlorodibenzo[p]dioxin (TCDD). The AHR is also considered to be an intriguing receptor, because it physiological ligands and its function it is unknown. Moreover, the lack of information on how mixtures of ligands influence receptor mediated toxicity is poorly understood. This uncertainty regarding variability in AHR mediated response from environmental mixtures is an important issue in our attempts to identify and prevent adverse human and ecological effects from the mixtures of AHR agonists that exist in the world. To help in this regard, new or better methodologies for rapid and cost-effective detection of toxicological agents that act through the AHR are needed. Therefore, we have developed an AHR expression system using a recombinant yeast cell of Saccharomyces cerevisiae to understand AHR ligand signaling. The advantages of this system are many; For example, yeast cells express a stable expression plasmid to produce the AHR protein and a separate operator-driven reporter gene to allow study of AHR’s transcriptional activity. Thus, thus system presents a more sensitive and rapid method to study AHR ligands. In order to demonstrate this, we have performed β-galactosidase reporter assays after exposing the yeast system to known AHR ligands. To demonstrate a dose-response curve, a direct-dilution of each ligand was added to 96-well inoculated microplate. The plates were incubated at 30 ºC for 2 hours in a shaker at 700 rpm. After this incubation time of chemical exposure, 50µl of Gal-Screen reagent was added to each well (Applied Biosystems), followed by incubation for 1 hour at 28 ºC; 700 rpm. The activation of AHR was measured by quantifying luminescence in the plate generated from the β-galactosidase activity. Preliminary data suggest that our yeast system is effective to identify a variety of AHR ligands with dose response relationships similar to that observed in human cells.

Hexadecane Degradation Stimulates Bacterial Bioplastic Production.  Christian D. Del Valle-Colón, Yomarie Bernier-Casillas, and José R. Pérez-Jiménez.  Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Hexadecane is an organic compound found in petroleum and biological waxes. Several bacterial species are specialized in hydrocarbon degradation; useful role to remediate polluted sites. Bacterial hexadecane-degraders have been found throughout diverse ecosystems in Puerto Rico, regardless of their nature and degree of disturbance. Prokaryotes are known to produce polyhydroxyalkanoates (PHA), a class of storage lipids that serve as endogenous carbon and energy source during starvation periods. PHA can replace synthetic polymers due to similar material properties. We hypothesized that bacterial hexadecane-degradation will stimulate the production of bioplastics inclusions as a preventive measure for the lack of certain nutrients. Our objective has been to study the production of PHA by bacterial strains capable of hexadecane degradation across ecosystems in Puerto Rico. Soil samples were collected at eight sites under diverse pollution regimes. Hexadecane-degrading bacteria (HDB) were isolated by aerobic cultivation on mineral media and subjected to 16S rDNA sequencing. Isolates were assessed for bioplastic (PHA) production by the Sudan Black stain method. Positive results were analyzed by adding Nile Red or Nile Blue A to media plates at a final concentration of 0.5 mg/ml. Fluorescence under UV light after 48 hours confirmed the production of PHA. A total of fifty-two putative HDB have been isolated. Among them, we found close relatives to Klebsiella, Pseudomonas, Ralstonia, Rhodococcus, Streptomyces, Bacilus, among others. All prospects have been able to grow in 1.0% hexadecane concentration. All Klebsiella strains (n=7) from Caño Martín Peña produced PHA; providing an additional alternative for industrial products reducing the contamination generated as residuals. HDB prevailed across Neotropical ecosystems, despite pollution level, are phylogenetically diverse. Vigorous growth suggests adaptation to persistent exposure to hexadecane. This collection of bioprospects provides novel isolates to deal with the pollution and references for further disclosure of biodegraders in nature.

Screening and partial characterization of moderate halophilic hydrolases and their biotechnological applications.  Iris V. Flores Rivera¹, Aramis Villafañe¹, Lilliam Casillas¹, Ezio Fasoli².  ¹Department of Chemistry, ²Department of Biology, University of Puerto Rico at Humacao, Humacao, PR, 00791.  Abstract: Hydrolases are widely used enzymes in biocatalytic process because of the low environmental impact of this methodology as well as their ability to catalyze synthesis of chiral alcohols, esters, and acids with high chemo-, regio-, and stereo-selectivity. Despite many examples of enzymes having been employed or considered for applications at industrial level, the complete shift from traditional chemical approach to greener biotechnological alternatives (biocatalysis) is hampered by the instability of enzymes when exposed to harsh conditions such as non-aqueous media or high temperature. With the aim of expanding this enzyme platform and finding new hydrolyses with high stability in a broad range of organic solvents, 153 moderately halophilic bacteria from tropical solar salterns at Cabo Rojo (Puerto Rico) were screened for extracellular esterase, lipase, protease, and epoxide hydrolase activities. The enzymatic assays for esterase, lipase, and protease were performed in 96-well plates using para-nitrophenyl derivatives as substrates. Adrenaline test was used for determining epoxide hydrolase activity. Of all the microorganisms screened, 45 isolates exhibited esterase activity, 12 were positive for lipases, 47 for proteases, and 28 for epoxide hydrolases. Several isolates showed multiple enzymatic activities. The positive hits were further assayed for stability at increasing concentrations of acetonitrile, dioxane, and DMSO (15%, 30% and 50% (v/v)). Three esterases, one lipase, two proteases, and two epoxide hydrolyses showed high activity in organic solvents compared to others. The isolates producing the selected enzymes were characterized biochemically and by 16S DNA analysis. All strains were found to belong to the Bacillus genus and can grow in 5-15% (w/v) salt concentration, pH 7.0 - 9.0, and at temperatures in the range of 37-50 °C. All the strains grow in up to a 30% concentration (v/v) of acetonitrile. Their related enzymes have similar optimal activity conditions but differently from their parent microorganisms show a basophile behavior. These activities detected and isolated from the salterns in PR offer very promising candidates for use as biocatalysts in the chemical and pharmaceutical industry. enzyme could be potentially useful in biocatalytic process requiring the use of organic solvents and high temperature or pH.

Bacterial Prospects for Decane-Degradation from the San Juan Bay Estuary System.  Janmary Colón-Alicea, Yomarie Bernier-Casillas, and José R. Pérez-Jiménez.  Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Contamination by organic compounds has been a consequence of industrial times. High concentrations can be harmful to all living things especially to ecosystems that thrive with the anthropogenic activities that take place each day. Decane is an organic compound derived from petroleum. Our objective is to study the aerobic bacterial degradation of decane in the San Juan Bay Estuary System (SJBES). Water samples were collected at different points in the SJBES. Bacteria were isolated in general media by serial dilution. Decane-degrading prospects were identified by aerobic cultivation on mineral salt media supplemented with decane as sole carbon source. Decane degradation was analyzed by colorimetric technique using the redox indicator 2,6-dichlorophenol indophenol. Twelve prospects have been identified so far with decane-degrading capabilities. All of them are bacillus that respires using oxygen (positive to catalase) with a combination of Gram positive (n=10) and Gram negative (n=2) strains. In the colorimetric technique 100% of the strains (n=6) were capable to start the degradation of decane in less than 24 hours. Future studies will include the characterization of decane-degrading bacteria by 16S rDNA barcoding. The prevalence of other aliphatic alkane degradation prospects across different ecosystems has been found across Puerto Rico. By means of this research, we concluded that decane-degrading bacteria could be found in the natural ecosystem regardless of the prevailing level of pollution.

Fungal Diversity in Green Litter Decomposition in a Hurricane Experiment  Johnathan Velázquez Cruz, Ivia Moreno, María F. Barberena-Arías, and Sharon A. Cantrell  School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Hurricanes generate disturbances in forests such as canopy opening, fallen trees and leaves which in turn alter physicochemical characteristics of the habitat, as well as, decomposer activity. Litter decomposition depends primarily on the interaction among climate, litter quality and biota; as a consequence, any change in habitats will result in changes in these factors. Identifying the changes in the fungal community structure in soil and forest floor litter can help understand the factors that influence ecosystem recovery. This study is part of the Canopy Trimming Experiment 2 performed by the Luquillo LTER at El Verde Field Station. For this, three blocks (A, B and C) were selected, each with two plots of 20m x 20m, one plot was used for control and the other was subject to canopy opening and debris addition (Trim plus debris).  In each subplot, litterbags with different mesh sizes (small, medium and large) were placed. This experimental design represents 3 blocks x 2 plots/block (1 trim+debris/ 1 control) x 3 subplots x 3 litterbag mesh sizes x 4 collecting times (3, 5, 12 and 24 weeks), for a total of 216 litterbags. A pool sample for each mesh size from the 3 subplots/per plot/time was obtained for DNA extraction. DNA was extracted using Power Soil DNA Isolation kit from MoBio. The TRFLP technique was used to obtain the profiles of the fungal communities of each sample using the fungal ITS region. The diversity between samples was analyzed using NMDS and UPGMA Cluster analysis using the Bray-Curtis similarity index. Two way Permanova shows significant differences in fungal communities between blocks, control and trim plus debris, and mesh size. No significant differences were observed through time. In general, the diversity of fungal communities increase in the trim plus debris treatment. This increase is mainly due to the addition of detritus which increases soil moistures. Fungi are the main decomposers of detritus in the forest floor and the effect of natural disturbances such as a hurricane on leaf litter microbial communities will help us understand how litter decomposition might be affected. This one component of a larger study that is analyzing the interaction between arthropods, microorganisms, nutrient mineralization and disturbances.

Response of Sulfate-Reducing Bacteria Communities to Simulated Hurricane at El Yunque Rain Forest in Puerto Rico.  Jonathan López Carrasquillo, and José R. Pérez-Jiménez.  Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Sulfate-reducing bacteria (SRB), that play a key role in the sulfur biogeochemical cycle, have been found in different anoxic environments, including mangrove sediments and elfin forest soils (El Yunque Rain Forest, Puerto Rico). Five life zones in El Yunque (tabonuco, palm, elfin, dry, and colorado forests) are developed in an elevation gradient subjected to natural disturbance and contrasting physicochemical conditions. A Canopy Trimming Experiment (CTE), that simulated the pass of a hurricane, has been already done in the Tabonuco forest. Samples have been collected at various times to monitor changes in microbiota. Our goal is to determine temporal heterogeneity of sulfate-reducing bacteria within the experimental plots, as detritus deposition of simulated hurricane effect. Soil samples are being collected from plots, every two weeks. Two treatments are considered: with and without detritus deposition trimmed from the local canopy. Total genomic DNA was extracted for amplification of the dissimilatory sulfite reductase gene (dsrAB) and terminal restriction fragment length polymorphisms (TRFLP) analysis of their MboI digests. According to the Dice similarity index, under no detritus deposition, the similarity decreased as time progress, 44% at time 0 to 17% at week 10. In contrast, diversity increased over time where detritus was added. Sulfidogenic abundance was lower in the absence of detritus (33 versus 94 phylotypes). The overall sulfidogenic community was dominated by major phylotypes decreasing over time. Only two phylotypes (184-, and 474-bp) persisted for both treatments and the five time periods examined. Our results suggest that a simple sulfidogenic community prevails in the Tabonuco forest soils that diversify as anoxic conditions are exacerbated by the addition of plant residues and their sulfate-containing residues are released to the soil. In the future, characterization of specific taxa presented will be elucidated. 

Toxicity of Functionalized Cd-Based Quantum Dots in Aquatic Models.  Julio A. Rivera de Jesús, and Sonia J. Bailón Ruiz.  ¹Department of Engineering; ²Department of Chemistry and Physics, University of Puerto Rico, Ponce, PR 00734.  Abstract: Quantum Dot are semiconductor nanocrystals with a ranging diameter of 2 nm - 10 nm. Due to their optical properties, these nanoparticles have several industrial and bio-medical applications like bio-imaging, the production of LED’s (light emitting diode), Photodynamic Therapy, among others. The present work is focused on the development of a protocol of ligand-exchange applied to CdSe(S) quantum dots. These water-stable nanoparticles were optically characterized by UV-Vis and Pholuminescence spectroscopies. UV-Vis analyzes evidenced the presence of a shoulder peak at 400 nm which suggests the formation of a solid like structure solution containing CdSe or CdS. It is known that nanostructures of CdSe or CdS should exhibit absorption peaks in the 550-576 nm or 389-409 nm range. Subsequently, the band gap energy of these nanomaterials was estimated at 2.32 eV which indicates a strong quantum confinement. In addition, the Photoluminescence spectra of produced nanoparticles showed a high emission peak at 553 nm and a full width at half maximum (FWHM) ~ 50 nm. The small value of the FWHM confirms a narrow size distribution in the sample, which contributes to the efficiency of quantum dots’ optical properties. The chemical interaction of these nanoparticles with bio-compatible molecules like glutathione was studied by Infrared spectroscopy and the presence of glutathione on the quantum dots surface confirmed that the ligand-exchange method was successfully achieved. Also, the toxicity of Cd on a nanoscale size and Cd2+ in solution was evaluated on representative organisms of the aquatic ecosystem. Preliminary studies suggested massive deaths at a concentration equal or greater than 100ppm of cadmium sulfate in a brine shrimp aquatic model. These results suggest that the nature of the organic cover on the quantum dots surface is tightly related to the intrinsic toxicity of these nanomaterials.

Antibacterial Effect of the Capsule and Leaf Extract of Azadirachta indica.  Karen E. Díaz Toledo¹, Katiria J. González-Rosario¹, Rafael Rodríguez², Piyali Bhattacharyya³, Anastacio Emiliano Sosa¹, Jonathan Otero¹, and José R. Pérez-Jiménez¹.  ¹Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778, ²University of Puerto Rico at Mayaguez, Mayaguez, PR 00861, ³School of Health Sciences, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Human history has been identified and used medicinal plants to combat many diseases. Azadirachta indica (neem), commonly found in various parts of India, is an evergreen tree that has many medicinal properties. Neem tree is the most researched tree in the world because it has been found that every part possesses a wide range of anti-bacterial, anti-inflammatory, anti-fungal and anti- cancer effects. The purpose of the study was to investigate the activity of Azadirachta indica capsule and leaf extract against six non-virulent strains. Qualitative and quantitative trials were made to determine the effect of both extracts in each bacterial strain. Bacteria were cultivated in tryptic soy broth (TSB) containing various concentrations of neem capsule and leaf extract (initial concentration of 10 mg/mL) at 37°C for 24 and 48 hours. Gram-negative bacteria were less susceptible through time and concentration for both extracts. For the quantitative trial, the Most Probable Method (MPN) was perform to determine if there was inhibition of the cells due to the neem capsule and leaf extract. The MPN shows that for 24 and 48 hours the extracts inhibit the growth of each strain. Afterward, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) was perform only in the capsule extract to study if the inhibition turned out to be a bacteriostatic or bactericidal effect. None of the bacteria grew in TSA in 24 and 48 hours showing that the inhibition was a bactericidal effect. Ultimately, we aim to proceed with the MIC and MBC in the leaf extract and identify the specific compounds that differ in each extract.

Dynamics of Microbial Groups in Response to Simulated Hurricane at El Yunque Rain Forest in Puerto Rico.  Karleen M. González-Rosario, Sharon A Cantrell-Rodríguez, and José R. Pérez-Jiménez.  Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Climate variability models predict increase in incidence and intensity of hurricanes. In Puerto Rico, hurricanes have impacted the Luquillo Rain Forest in many occasions resulting on canopy debris deposited in the forest floor. Inhabiting microbes face input of complex plant biomass, increases in sunlight, and alterations in redox potential that impact their prevalence and contributions to biogeochemical cycles. A Canopy Trimming Experiment (CTE), that simulated the pass of a hurricane, has been done in the Tabonuco forest. Our goal is to determine temporal heterogeneity of three microbial groups (bacteria, fungi, and ammonium oxidizing archaea) in response to detritus deposition of simulated hurricane effect. Soil samples are being collected from plots, at different times. Two treatments are considered: with and without detritus deposition trimmed from the local canopy. Bacteria, fungi, and ammonium oxidizing archaea are being characterized independently by the molecular analyses of four distinctive genes (16S rDNA, ITS, and ammonium monooxygenase). Bacteria was homogeneous over time for the same plot suggesting microbial succession in which rare microbiota became more prevalent over time. In contrast, diversity increased over time where detritus was added. Bacterial and fungal communities exhibited spatial variation regardless the availability of plant debris. In contrast, microbial functional groups examined demonstrated greater heterogeneity in response to plant debris addition (treatments). In the future, we will analyze the effect of a hurricane on the structure of soil microbial communities, characterization of specific taxa, qPCR and Next Generation Sequencing.

Bioprospecting for Bacterial Xylose-Fermentation Among Contrasting Ecosystems.  Luis Eduardo Serrano-Torres, and José R. Pérez-Jiménez.  Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Globally, energy needs have pressured the quality and availability of air, water, and plant feedstock. There is an urgent need to produce energy without depleting nonrenewable resources. The source of biomass for ethanol production has brought controversies and innovation to the biofuel research. Lignocellulosic waste, resulting from food and forestry industries, is considered an alternative source for bioethanol that protect the environment and is neutral to feedstock. Since xylose forms much of the lignocellulosic material, it is important to find efficient ways to convert this sugar into ethanol, such as fermentation by bacteria, fungi or yeasts. Bacteria models are considered more versatile than yeast and manageable than fungi. The objective of this study is to isolate bacteria, across contrasting ecosystems, capable to convert xylose into ethanol by fermentation. Samples were collected from soils subjected to sustainable agriculture practices. General bacterial fraction was cultivated in general media. Isolates were tested on a reformulated media for xylose fermentation. Putative xylose-fermenting bacteria were characterized by Gram stain, catalase test and 16S rRNA gene sequence. Over one hundred bacteria demonstrated xylose fermentation. Among them, 16S rRNA sequencing provide close homologues to Pseudomonas putida, Citrobacter sp., Enterobacter sp., Burkholderia cenocepacia, Klebsiella pneumoniae, Stenotrophomonas sp., Bacillus sp., Klebsiella oxytoca, Alcaligenes faecalis, and Enterobacter aerogenes. Thus, diverse bacteria were found capable of fermenting xylose among contrasting ecosystem. The research will continue completing characterization of the collection, including kinetics for ethanol production. Ultimately, fittest strains will be tested for upscale ethanol production.

Evaluation of The Organic Cover and The Nanoparticle Size on The Toxicity of Quantum Dots.  Nadja M. Maldonado Luna, and Sonia Bailón Ruiz.  ¹Department of Engineering; ²Department of Chemistry and Physics, University of Puerto Rico, Ponce, PR 00734.  Abstract: Quantum Dots (QDs) for biomedical applications need to be bio-compatible, water stable and nontoxic. This research is addressed on the generation of water-stable CdTe/S quantum dots with different coating species such as cysteine an amino acid, Glutathione a peptide, and Albumin a protein. It is expected that nanoparticles with different coatings can behave in different ways at cellular level by interacting with cell membrane, mitochondria or nucleus and can impart adverse effect like damage and potential cellular death. Two size of CdTe/S quantum dots were previously synthesized in aqueous phase by microwave irradiation and optically characterized using a UV-Vis spectrophotometer and a Spectrofluorometer. CdTe/S QDs of larger size evidenced a shoulder peak in the range 580 nm-600 nm which suggested the formation of a structure like a solid solution containing Cd, Te and S. High emission peak at 640 nm was observed, characteristic of nanomaterials based in CdTe, and a full width at half maximum (FWHM) at 62 nm indicating a narrow size distribution of nanocrystals. Whereas, CdTe/S QDs of smaller size revealed a band gap peak in the range 550 nm -570 nm, a fluorescence peak centered at 574 nm and a FWHM at 48 nm. Glutathione was used to functionalize the QDs containing Cd, Te and S as an attempt on obtaining a biocompatible and nontoxic surface. Functionalized QDots will be structurally and optically characterized using XRD and UV-Vis/PL spectroscopies, respectively. The toxicity of cadmium acetate Cd(CH₃CO₂)₂ in aquatics organisms were evaluated through experiments of exposure of brine shrimp Artemia Salina to cadmium solutions for 18-24 h and 36-48 h. These experiments showed that as the concentration of Cd(CH₃CO₂)₂ increased, the mortality rate increased in Artemia Salina. After 18-24 h of exposure to 1000 ppm cadmium solution, 0% of the aquatic organisms where alive; and after 36-48 h of exposure to 500 ppm cadmium solution, 0% where alive. The mortality observed can be attributed to the generation of reactive oxygen species by cadmium solutions in Artemia Salina.

Diet, Nutrition and the Prevention of Chronic Diseases.  Piyali Bhattacharyya, Ángel Belén Rivera, and Jayson A. Díaz Corcino.  School of Health Sciences, Universidad del Turabo, Gurabo, PR 00778.  Abstract: This investigation presents a framework descriptive of the situation local and international related to the Nutrition and chronic diseases, including the rate of mortality and its relation with obesity and overweight. The Chronic diseases means -a long-term condition e.g., obesity, diabetes, cardiovascular disease, cancer, HIV etc. May be prevented or delayed with lifestyle changes e.g., healthier eating and more physical activity. The purpose of this intervention is to show that the diseases chronic are prevented if it takes in consideration a serious of changes of style of life and of political public that may lead to modifications to the life significant and get them results desired in reduce the rate of mortality and them diseases chronic. The methodology that is use was descriptive since are used brochures that those participating had that fill and answer a series of questions that have relationship with his State of health. The data was collected from a series of agencies which provided information necessary to the respect.1.9 million people die as a result of physical inactivity; 2.7 million people die as a result of low fruit and vegetable consumption; 2.6 million people die as a result of being overweight or obese. The discussion shows the change of lifestyles and practice of healthy eating habit can prevent those chronic diseases and disorders. Good nutrition is key to preventing and correcting the obesity epidemic worldwide.

Bio-catalysis- Screening and Partial Characterization of Moderate Halophilic Hydrolases with Good Stability in Organic Solvents.  Steven Toro De León, and Ángel Miranda Santiago.  University of Puerto Rico at Humacao, Humacao, PR, 00791.  Abstract: The use of Esterases in organic synthesis is of immense significance because of the low environmental impact of this methodology as well as the ability of these enzymes to catalyze synthesis of chiral alcohols, esters and acids with high chemo-, regio- and stereo-selectivity. Despite many examples having been employed or considered for applications at industrial level, the complete shift from traditional chemical approach to greener biotechnological alternatives (biocatalysis) is hampered by the instability of esterases when exposed to harsh conditions such as non-aqueous media or high temperature. Our hypothesis is that new esterases from organisms occupying extreme hypersaline environments (The salterns of Cabo Rojo, PR) will be more active and stable at the harsh experimental conditions that are found in the laboratory (presence organic solvents or ionic liquids, high temperature and extreme pH). Initially in the investigation we have studied the activity and stability of esterases isolated from the Saltern of Cabo Rojo (PR) in presence of organic solvents, high concentration of salt and different Ph. We prove that in the case of halophilic enzymes, the presence of organic solvents will stabilize the folded structure by acting as salt mimicking agents in solvent/water mixture. The objective of this project is to study the Chemo-, regio- and stereo selectivity of the different enzymes towards the above substrates will be evaluated using GC/HPLC equipped with chiral columns. One of the esters of interests is the 1,2-O-isopropylideneglycerol (solketal) which is an important intermediate at different steps of the synthesis of glycerophospholipids, β-blockers, carnitine, α-adrenergic antagonist, thromboxane synthetase inhibitor and antitussive drugs. We will test the set of enzymes with the aim of finding more stable and enantioselective hydrolases for the kinetic resolution of solketal in hydrolysis and/or esterification reactions. The implantation of this project will take one year. One publication in a peer review Journal and several posters and oral presentation are expected outcome of this work

Variants of Sorghum as Substrate for Lignin Degradation by Bacteria.  Tiffany Del Valle-González, Solimar García-Torres, and José R. Pérez-Jiménez.  Puerto Rico Institute for Microbial Ecology Research, School of Natural Sciences and Technology, Universidad del Turabo, Gurabo, PR 00778.  Abstract: Lignin is a recalcitrant heteropolymer found in the cell wall of plants to confer structural strength and delay biodegradation. It is the most abundant constituent of plant debris and biomass with potential application as a source for biofuel. Several fungal genera and few bacterial taxa are known to degrade lignin. Lignin partition can release highly energetic components embedded in the plant biomass not used as food source. Forage sorghum (Sorghum vulgare) is considered a potential energy crop due to its reduced lignin contents; grow under adverse conditions, and demands simple treatments. The main hypothesis is if mesophilic lignin-degrading bacteria can grow in variants of sorghum as the only carbon source, then lignin thermal treatments could be replaced. The specific aim for this project is to study the growth response of various lignin-degrading bacteria to various components of sorghum as sole carbon source. Lignin-degrading bacteria were isolated from soil at Universidad del Turabo, and water at the San Juan Bay Estuary system, both in Puerto Rico. Sorghum components (leaves and fresh stem) were added independently, as sole carbon source, to mineral base liquid and solid media. Growth was demonstrated qualitatively by colony biomass on solid media and quantitatively by optical density on liquid media. Twenty bacterial strains capable of lignin deconstruction were isolated. Partial sequencing of the 16S rRNA genes resulted in Lysinibacillus sp. and Acinetobacter sp. as closest homologous. Fresh inner stem sorghum resulted on more biomass than other substrates. These novel strains of lignin-degrading bacteria can provide an alternative for biofuel production instead of fossil fuels. Clean energy will be the focus for the next years as fossil fuels are in continual depletion.