Lidieth Uribe

Efficient energy harvesting for Microbial Fuel Cell dedicated to Wireless Sensor Network

Microbial Fuel Cell (MFC) is novel technology for harvesting a fully sustainable zero emissions bioenergy that, by means of dedicated electronic circuits, suitably can be used for the proper functioning of a single Wireless Sensor Network (WSN) node. MFC is a bioreactor that transforms energy stored in chemical bonds of organic compounds into electrical energy. Low-power electronic devices allow now the design of electronic systems characterized by very low energy consumption. Accordingly, this allows the use of power sources based on energy harvesting techniques that involve clean renewable sources as MFC The first section of the paper introduces technological characteristics of the cell. The second one briefly examines the gap between electrical supplying of the cell and the energy requirements of WSN nodes. The design requires the usage of a step-up DC/DC converter, so the last part of the paper deals with the problems that occur when you want realize a system including a single MFC reactor for powering a single WSN node.

Effects of coffee processing residues on anaerobic microorganisms and corresponding digestion performance

The objective of this study was to delineate the effects of different coffee processing residues on the anaerobic microbes and corresponding digestion performance. The results elucidated that mucilage-rich feed enhanced the accumulation of methanogens, which consequently led to better digestion performance of biogas production. Fifty percent more methane and up to 3 times more net energy (heat and electricity) output were achieved by the digestion of the mucilage-rich feed (M3). The microbial community and statistical analyses further elucidated that different residues in the feed had significant impact on microbial distribution and correspondingly influenced the digestion performance.

Survival of selected lactic acid bacteria isolated from pineapple waste in refrigerated pineapple juices

The aim of this research was to isolate and identify lactic acid bacteria (LAB) from pineapple waste. The survival in refrigerated pineapple juices, of a selected isolate with potential probiotic properties, was also studied. The 16S rRNA and pheS partial genes were used to identify LAB, multilocus sequence typing (MLST) genes were used in order to separate strains grouping with Lactobacillus casei and L. paracasei phylogenetically. Tests for survival at pH 2.0, resistance to lysozyme and tolerance to bile salts were used to screen the strains for potential probiotic properties. A L. fermentum isolate was used for the survival study. Three types of pineapple juice made from pulp, a blend of pulp and peel (80:20), and peel extract were inoculated to approximately 106 CFU/mL with L. fermentum and stored at 4 °C for up to six weeks. The physicochemical composition of juices, including concentration of fermentable sugars and organic acids, total solids content, soluble solids content, titratable acidity and pH, was determined during the survival study. Two genera and five species were identified. Pineapple juices supported the survival of L. fermentum during refrigerated storage but the population of the bacteria decreased over time regardless of the juice type. Juice made from pulp was a more suitable vehicle for the survival of the selected LAB. Some of the juice physicochemical properties, including sugars and organic acids content, pH and titratable acidity, varied significantly (P<0.05) during storage. Further sensory studies are necessary to evaluate consumer acceptance of juices containing the selected isolate. IMPORTANCE Lactic acid bacteria (LAB), isolated from pineapple waste, were phylogenetically analyzed and characterized in regards to their tolerance to pH 2.0, lysozyme and bile salts; showing their potential as probiotic strains, if health benefits associated to their ingestion are eventually confirmed. Moreover, pineapple juice supported the survival of Lactobacillus fermentum, isolated from the same food matrix, during refrigerated storage at 4 °C. Among the three pineapple juices tested (pulp, pulp + peel and peel), L. fermentum survived better in juice made from pulp. However, significant variations were observed overtime in some of the physicochemical properties of the juices including sugars and organic acids content, pH and total titratable acidity.

Corrigendum to “Effects of coffee processing residues on anaerobic microorganisms and corresponding digestion performance” [Bioresour. Technol. 245 (2017) 714–723]

a Agricultural Engineering, University of Costa Rica, San José, Costa Rica Agronomy Research Center, University of Costa Rica, San José, Costa Rica National Institute for Innovation and Transfer of Agricultural Technology, Ministry of Agriculture, San José, Costa Rica d Fabio Baudrit Experimental Station, University of Costa Rica, San José, Costa Rica Microbiology and Molecular Genetics, Michigan State University, MI, USA Danish Genome Institute, Aarhus, Denmark g Cellular and Molecular Biology Research Center, University of Costa Rica, San José, Costa Rica Anaerobic Digestion Research and Education Center, Biosystems and Agricultural Engineering, Michigan State University, MI, USA