Bioprospecting of Ureolytic Bacteria From Laguna Salada for Biomineralization Applications

The processes of biomineralization, mediated by ureolytic bacteria, possess a wide range of technological applications, such as the formation of biocements and remediation of water and soil environments. For this reason, the bioprospecting of new ureolytic bacteria is interesting for its application to these technologies, particularly for water treatment. This study demonstrates the isolation, selection, and identification of halotolerant ureolytic bacteria from Laguna Salada (inland from Atacama Desert) and the evaluation of their ability to precipitate calcium carbonate crystals in freshwater in the presence of calcium ions, as well as the ability to induce the precipitation of crystals from different ions present in seawater. Twenty-four halotolerant ureolytic bacteria whose molecular identification gives between 99 and 100% identity with species of the genus Bacillus, Porphyrobacter, Pseudomonas, Salinivibrio, and Halomonas were isolated. When cultivated in freshwater, urea, and calcium chloride, all species are able to biomineralize calcium carbonate in different concentrations. In seawater, the strains that biomineralize the highest concentration of calcium carbonate correspond to Bacillus subtilis and Halomonas sp. SEM–EDX and XRD analyses determined that both bacteria induce the formation of 9–33% halite (NaCl), 31–66% monohydrocalcite (CaCO3 × H2O), and 24–27% struvite (MgNH4PO4 × 6H2O). Additionally, B.subtilis induces the formation of 7% anhydrite (CaSO4). In seawater, B.subtilis and Halomonas sp. were able to precipitate both calcium (96–97%) and magnesium (63–67%) ions over 14 days of testing. Ion removal assays with B.subtilis immobilized in beads indicate a direct relationship between the urea concentration and a greater removal of ions with similar rates to free cells. These results demonstrate that the biomineralization mediated by bacterial urea hydrolysis is feasible in both freshwater and seawater, and we propose its application as a new technology in improving water quality for industrial uses

Effect of Static Magnetic Fields on the Composition of Marine Biofouling in Seawater Transportation Pipelines

The use of seawater for mining purposes in Chile has progressively increased in recent years as fast as the interest on the negative effects of biofouling on the inner part of pipelines used to transport seawater. To prevent biofouling, chemical antifouling compounds are traditionally used, thus, causing negative environmental impacts. The aim of this research has, therefore, been to evaluate the efficiency of static magnetic fields (SMF) generators to mitigate the biofouling. Hence, experimental activities have been conducted on high density polyethylene (HDPE) pipes equipped with neodymium magnets during two experimental periods in the year of 2019, i.e., autumn–winter (A–W) and spring–summer (S–S), and under two types of SMF, i.e., continuous-type (PCS) and pulse-type (PPS). Physicochemical parameters and cell viability of microorganisms composing the biofilm were investigated. Metagenomic analyses on biofilm were conducted as well. The results showed that the cell viability was the highest, i.e., 757,780 cells/cm2, during S–S and the lowest, i.e., 349,151 cells/cm2, in A–W, both under PCS. In S–S, as well as A–W, biofilm was characterized for the most abundant eukaryotic operational taxonomic units (OTUs) under PPS conditions. The presence of OTUs, such as Articiflavibacter spp., Chaetonotida spp. and Desmodorida spp., was observed only from SMF tests.This research was funded by ANID/FONDEF/IDEA, grant number ID15I10487, and, in part, by the Programa Semilleros de Investigación: “Caracterización de una línea base para el análisis y determinación de los componentes celulares”, by the Fondo para el Desarrollo en investigación científica y/o tecnológica de actividades de titulación de pregrado 2018: “Producción de metabolitos de alto valor económico mediante exposición a un campo magnético estático tipo continuo y tipo pulso en las microalgas Scenedesmus obliquus y Nannochloropsis gaditana”, by Programa Asignación año 2021 de Asistentes de investigación de la Universidad de Antofagasta código ANT20992 and partially supported by “Antonio Panico visit at the Universidad de Antofagasta” and supported by MINEDUC-UA project code ANT1999

Wastewater, reclaimed water, and seawater utilization in the production of microalgae-based fuels

Biofuel production from microalgae is affected by the cost of the cultivation of microalgal biomass. The cultivation of microalgae for third-generation biofuels in wastewater, reclaimed water, and seawater could be a cost-effective way to obtain microalgal biomass. This option would serve to reduce costs and treat wastewaters and reclaimed water at the same time. Autotrophic and mixotrophic cultivation make use of wastewater and nutrients, using light and CO2 to obtain high percentages of nitrogen and phosphorous removal. The advantage of microalgae grown in this way is twofold: wastewater treatment and microalgal production without the addition of water and nutrients. Biofuels from microalgae grown in this way would replace fossil fuels with renewable and carbon-neutral fuels in a sustainable way and contribute to the circular economy of water resources. In this review, an updated evaluation of microalgal cultivation in wastewater, reclaimed water, and seawater together with biofuel generation will be shown.Peer reviewe

El mercado inmobiliario de megaproyectos : una nueva alternativa para constructuiva-Pemac

Constructiva - PEMAC es una organización promotora y constructura de proyectos inmobiliarios, operando bajo el sistema de autoconstrucción desde el 200 con un proyecto y luego a partir del 2001 con un mayor crecimiento

Improvement proposal to reduce stock outages of the company RW Outfitters Perú S.A.C.

RW Outifitters Perú S.A.C. es una empresa dedicada a la importación y comercialización de productos de seguridad personal EPP’s. Cuenta con una vasta experiencia en el sector industrial, de más de 10 años, comercializando marcas de prestigio y calidad. La empresa en análisis tiene diversos problemas que hemos llevado a un diagrama de Pareto para identificar el problema principal, identificando que es “demora en entrega de productos”; luego, se ha realizado un diagrama de ishikawa para identificar las causas raíz y, por último, hemos colocado las causas en otro diagrama de Pareto para identificar la causa principal, dando como resultado el “quiebre de stock”. Considerando buscar una solución al problema de “demora en entrega de productos debido al quiebre de stock”, se ha realizado una investigación de antecedentes de solución, lo cual nos ayudó a identificar varios métodos de solución como: ABC, WMS y S&OP. Considerando las tres alternativas de solución más adecuadas para la empresa, se realizó un análisis comparativo de ventajas y desventajas entre ABC, WMS y S&OP; luego, se realizó una matriz de selección de alternativas siendo el método S&OP el de mayor puntaje obtenido. Por último, se detalla la factibilidad y viabilidad de la implementación del método S&OP en la empresa. Por tal motivo, se concluye que el método S&OP es el más adecuado para brindar solución al problema de la empresa y se recomienda su implementación para poder evitar la demora en entrega de productos debido al quiebre de stock.RW Outifitters Perú S.A.C. is a company dedicated to the import and marketing of PPE personal safety products. It has vast experience in the industrial sector, more than 10 years, marketing prestigious and quality brands. The company under analysis has various problems that we have taken to a Pareto diagram to identify the main problem, identifying that it is “delay in product delivery”; Then, an ishikawa diagram has been made to identify the root causes; Finally, we have placed the causes in another Pareto diagram to identify the main cause, resulting in the “stock outage”. Considering searching for a solution to the problem of “delay in delivery of products due to stock out”, a background investigation of a solution to the same problem has been carried out, which helped us identify several solution methods such as: ABC, WMS y S&OP. Considering the three most appropriate solution alternatives for the company, a comparative analysis of advantages and disadvantages was carried out between ABC, WMS and S&OP; Then, a selection matrix of alternatives was made, with the S&OP method being the one with the highest score obtained. Finally, the feasibility and viability of implementing the S&OP method in the company is detailed. For this reason, it is concluded that the S&OP method is the most appropriate to provide a solution to the company's problem and its implementation is recommended to avoid delays in product delivery due to stock out.Trabajo de Suficiencia Profesiona

Biomineralization Mediated by Ureolytic Bacteria Applied to Water Treatment: A Review

The formation of minerals such as calcite and struvite through the hydrolysis of urea catalyzed by ureolytic bacteria is a simple and easy way to control mechanisms, which has been extensively explored with promising applications in various areas such as the improvement of cement and sandy materials. This review presents the detailed mechanism of the biominerals production by ureolytic bacteria and its applications to the wastewater, groundwater and seawater treatment. In addition, an interesting application is the use of these ureolytic bacteria in the removal of heavy metals and rare earths from groundwater, the removal of calcium and recovery of phosphate from wastewater, and its potential use as a tool for partial biodesalination of seawater and saline aquifers. Finally, we discuss the benefits of using biomineralization processes in water treatment as well as the challenges to be solved in order to reach a successful commercialization of this technology

Biochemical characterization and inhibitory effects of dinophysistoxin-1, okadaic acid and microcystine l-r on protein phosphatase 2a purified from the mussel Mytilus chilensis.

Protein phosphatases are involved in many cellular processes. One of the most abundant and best studied members of this class is protein phosphatase type-2A (PP2A). In this study, PP2A was purified from the mussel Mytilus chilensis. Using both SDS-PAGE and size exclusion gel filtration under denaturant conditions, it was confirmed that the PP2A fraction was essentially pure. The isolated enzyme is a heterodimer and the molecular estimated masses of the subunits are 62 and 28 kDa. The isolated PP2A fraction has a notably high p-NPP phosphatase activity, which is inhibited by NaCl. The hydrolytic p-NPP phosphatase activity is independent of the MgCl2 concentration. The time courses of the inhibition of the PP2A activity of p-NPP hydrolysis by increasing concentrations of three phycotoxins that are specific inhibitors of PP2A are shown. Inhibitions caused by Okadaic acid, dinophysistoxin-1 (DTX1, 35-methylokadiac acid) and Microcystine L-R are dose-dependent with inhibition constants (Ki) of 1.68, 0.40 and 0.27 nM respectively. Microcystine L-R, the most potent phycotoxin inhibitor of PP2A isolated from Mytilus chilensis with an IC50 = 0.25 ng/ml, showed the highest specific inhibition effect an the p-NPP hydrolisis. The calculated IC50 for DTX1 and OA was 0.75 ng/ml and 1.8 ng/ml respectively