Multisubstrate Monod Kinetic Model for Simultaneous Degradation of Chlorophenol Mixtures

Chlorophenols (CPs) are persistent and highly toxic compounds rated as priority pollutants by the Environmental Protection Agency (EPA). Frequently, these compounds are present as mixtures of CPs in industrial wastewaters. Therefore the study of biodegradation on mixed pollutants is an important aspect of biodegradation and wastewater treatment. In this work, we studied the multisubstrate degradation of CPs by a mixed culture of Pseudomonas aeruginosa and a novel Acromobacter sp. capable of using pentachlorophenol (PCP), 2,4,6 trichlorophenol (2,4,6 TCP) and 2,3,5,6 tetrachlorophenol (2,3,5,6 TeCP) as the sole sources of carbon and energy. The main objective of this work was to evaluate the effect of substrate mixtures on the degradation kinetics of PCP. Batch experiments were conducted with each CP separately and in mixtures of PCP + 2,4,6 TCP, PCP + 2,3,5,6 TeCP, and PCP + 2,4,6 TCP + 2,3,5,6 TeCP. Based upon our results we have concluded that the simultaneous degradation of CPs is a key factor contributing to the improvement of PCP degradation. The kinetic parameters for PCP and 2,4,6 TCP were obtained by fitting the data to a Monod kinetics model. Using such parameters, the model was able to predict simultaneous multisubstrate degradation of PCP with others CPs

Degradation of chlorophenol mixtures in a fed-­batch system by two soil bacteria

This work was undertaken to investígate the effect of variations of the feed rate on a fed-batch set-up used to degrade xenobiotics. The mixture of substrates was composed of PCP, 2,4,6 TCP and 2,3,5,6 TeCP (pentachlorophenol, 2,4,6 trichlo- rophenol and 2,3,5,6 tetrachlorophenol respectively). Two acclimated bacteria isolated from soil were used: Pseudomonas aeruginosa and Achromobacter sp. nov. The different flow rates tested were: I: 0.5 ml*min-1, II: 1.67 ml*min$latex ^{}$-1 and III: 2.00 mf-min'1. Our results show that during fed-batch operation the 2,4,6 TCP exhibits an earlier degradation than the other com- pounds, for all of the flow rates tested. This indicates that in this case the degradation of the most recalcitrant compounds (PCP and 2,3,5,6 TeCP) is benefited by the increase in biomass ofbacteria, due to the metabolisation of a less recalcitrant compound (2,4,6 TCP). The defined parameter, specific degradation rate (SDR), was demonstrated to be very useful for comparing the degradation abilities at different flow rates of a fed-batch system. The degradation efficiencies were shown to be higher than 90% for all of the cases and to decrease as the feed rate increases. However, the SDR, a parameter that involves the rate of degradation and the biomass, increases as the flow rate increases. At a feed flow rate of 2 mf-min'1 SDR reaches a maximum of 12.476 x 10'10 mgCP-M-CFU'1. Finally, among the feed flows tested, taking into account both the degradation efficiency and the SDR, 2 ml-min-1 is the most convenient flow rate for chlorophenol degradation in fed-batch Systems. An even higher degradation efficiency (97%) can be achieved by using the feed rate of 2 mf-min'1 followed by an additional batch post-treatment of2 h, with a SDR of 13.136 x 10-10 mg CP-h1-CFU1

Chemotactic response of the flavonoid daidzein and its effect on the composition of the rumen bacterial community

Daidzein is one of common metabolites in plants and has chemotactic effect on soil bacteria that colonize the plants. There are several tests to assess bacterial chemotaxis, but none focused on rumen bacteria. Therefore, the aim of this study was to test the chemotactic response of the rumen microflora towards daidzein using a standardized bacterial chemotaxis assay. It consisted in a modifying capillary technique and employing technology for measuring in vitro gas production. Ruminal fluids and cellulose were used as controls. The response of bacteria to daidzein was greater than the response to cellulose, supporting the hypothesis that when fodder is chewed by the ruminant it releases daidzein which can attract rumen bacteria towards feed particles (chemotaxis) for attachment and subsequent degradation

Monitoring the characteristics of cultivable halophilic microbial community during salted-ripened anchovy (<i>Engraulis anchoita</i>) production

The halophilic microbial community of the salted-ripened anchovy process was studied. Samples from raw materials (salt and fresh anchovies) and from the stages of brining and ripening were collected and analyzed for their bacterial counts at 15 and 20% NaCl. No halophilic colonies were found in fresh anchovy and counts of about 103 CFU/g were determined in salt samples. A fluctuation of bacterial counts during the process was found. At the end of brining, ~104 CFU/g were determined in anchovy samples and this value was reduced to not detectable counts at the beginning of the ripening stage. After one month, counts increased to ~104 CFU/g and remained stable until the end of the process. From each sample, colonies having different morphotypes were isolated and submitted to a macro and microscopic characterization, a study of salt requirement for growth, and biochemical and phenotypic tests. The results were submitted to Univariate, Bivariate and Multiple Correspondence Factorial Analysis (MCFA). A total of 79 colonies were isolated during the salting-ripening anchovy process. Among the isolates, about 40–50% was positive for indole production and lipolytic activity and a 25% showed ability to produce H2S and proteolytic capacity. Proteolytic and lipolytic activities were well balanced along the process and resulted independent from the isolation stage, which is a desirable condition due to the contribution of microbial proteolysis and lipolysis to the development of texture and final aroma, respectively. H2S and indole producers practically were not detected during ripening. This fact is important because indole and H2S are associated with the development of off-flavors and spoilage in salted fish products. MFCA and Cluster Analyses complemented the Bivariate Analyses. The factor map showed proximity between the isolates from salt samples and from ripening. Isolates were statistically clustered in two groups. Cluster 1 grouped non-desirable activities (H2S and indole production) with cultures proceeding from brining whereas Cluster 2 related isolates mainly from salt samples and during ripening with some desirable microbial capacities (Cytochrome oxidase activity and non-H2S and non-indole production). These results would indicate that during the ripening process of salted anchovies, a natural selection of beneficial microorganisms for the development of the typical product sensory attributes occurred.Centro de Investigación y Desarrollo en Criotecnología de AlimentosFacultad de IngenieríaComisión de Investigaciones Científicas de la provincia de Buenos Aire

Monitoring the characteristics of cultivable halophilic microbial community during salted-ripened anchovy (<i>Engraulis anchoita</i>) production

The halophilic microbial community of the salted-ripened anchovy process was studied. Samples from raw materials (salt and fresh anchovies) and from the stages of brining and ripening were collected and analyzed for their bacterial counts at 15 and 20% NaCl. No halophilic colonies were found in fresh anchovy and counts of about 103 CFU/g were determined in salt samples. A fluctuation of bacterial counts during the process was found. At the end of brining, ~104 CFU/g were determined in anchovy samples and this value was reduced to not detectable counts at the beginning of the ripening stage. After one month, counts increased to ~104 CFU/g and remained stable until the end of the process. From each sample, colonies having different morphotypes were isolated and submitted to a macro and microscopic characterization, a study of salt requirement for growth, and biochemical and phenotypic tests. The results were submitted to Univariate, Bivariate and Multiple Correspondence Factorial Analysis (MCFA). A total of 79 colonies were isolated during the salting-ripening anchovy process. Among the isolates, about 40–50% was positive for indole production and lipolytic activity and a 25% showed ability to produce H2S and proteolytic capacity. Proteolytic and lipolytic activities were well balanced along the process and resulted independent from the isolation stage, which is a desirable condition due to the contribution of microbial proteolysis and lipolysis to the development of texture and final aroma, respectively. H2S and indole producers practically were not detected during ripening. This fact is important because indole and H2S are associated with the development of off-flavors and spoilage in salted fish products. MFCA and Cluster Analyses complemented the Bivariate Analyses. The factor map showed proximity between the isolates from salt samples and from ripening. Isolates were statistically clustered in two groups. Cluster 1 grouped non-desirable activities (H2S and indole production) with cultures proceeding from brining whereas Cluster 2 related isolates mainly from salt samples and during ripening with some desirable microbial capacities (Cytochrome oxidase activity and non-H2S and non-indole production). These results would indicate that during the ripening process of salted anchovies, a natural selection of beneficial microorganisms for the development of the typical product sensory attributes occurred.Centro de Investigación y Desarrollo en Criotecnología de AlimentosFacultad de IngenieríaComisión de Investigaciones Científicas de la provincia de Buenos Aire

Hydrocarbon biodegradation and dynamic laser speckle for detecting chemotactic responses at low bacterial concentration

We report on the biodegradation of pure hydrocarbons and chemotaxis towards these compounds by an isolated chlorophenol degrader, Pseudomonas strain H. The biochemical and phylogenetic analysis of the 16S rDNA sequence identified Pseudomonas strain H as having 99.56% similarity with P. aeruginosa PA01. This strain was able to degrade n-hexadecane, 1-undecene, 1-nonene, 1-decene, 1-dodecene and kerosene. It grew in the presence of 1-octene, while this hydrocarbons is toxic to other hydrocarbons degraders. Pseudomonas strain H was also chemotactic towards n-hexadecane, kerosene, 1-undecene and 1-dodecene. These results show that this Pseudomonas strain H is an attractive candidate for hydrocarbon-containing wastewater bioremediation in controlled environments. Since the classical standard techniques for detecting chemotaxis are not efficient at low bacterial concentrations, we demonstrate the use of the dynamic speckle laser method, which is simple and inexpensive, to confirm bacterial chemotaxis at low cell concentrations (less than 105 colony-forming unit per millilitre (CFU/mL)) when hydrocarbons are the attractants.Fil: Nisenbaum, Melina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Sendra, Gonzalo Hernán. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Gilbert, Gastón Alfredo Cerdá. Obras Sanitarias Mar del Plata; ArgentinaFil: Scagliola, Marcelo. Obras Sanitarias Mar del Plata; ArgentinaFil: González, Jorge Froilán. Universidad Nacional de Mar del Plata; ArgentinaFil: Murialdo, Silvia Elena. Universidad Nacional de Mar del Plata; Argentin

Diversity of fungi in bottled water in Jeddah, Saudi Arabia

The occurrence of fungi in drinking water systems has received increased attention over recent decades and fungi are now generally accepted as drinking water system contaminants. However, fungal contamination of bottled water has received little attention. Forty unopened bottled water samples, of different trademarks, were collected from various localities in Jeddah city, Saudi Arabia and analyzed for fungal contamination: 1) immediately after opening the bottles; and 2) after closing and storing them for 180 and 365 days. The fungal species were identified under a compound microscope followed by molecular sequencing. At least one fungal species were found in 58% of the bottles. In total, 18 fungal species belonging to 11 fungal genera were identified. Rhizopus nigricans and seven different species of Aspergillus were found to frequently contaminate the bottled water samples. Penicillium sp. were found in one sample. The 180 days storage of opened and reclosed bottles did not substantially affect the abundance of fungi or the species found. Some of the fungi identified may be pathogenic and the contamination of fungi in bottled water should be considered during the processing of water

Haloargentinum marplatensis gen. nov., sp. nov., a novel extremely halophilic bacterium isolated from salted-ripened anchovy (Engraulis anchoita)

A facultative aerobic, Gram-negative, motile, non-endospore forming and extremely halophilic bacterium, strain 11aii⊺, isolated from salted-ripened anchovy, was examined using a polyphasic approach to characterize and clarify its phylogenetic and taxonomic position. Sequences of the 16S rRNA gene revealed close relationships to species of the genera Lentibacillus and Virgibacillus (94.2% similarity). The organism grew optimally in the presence of 20-35 % NaCl. The major fatty acids of strain 11aii⊺ were C16:0 (42.1%) and anteiso-C15:0 (31.2%) and also presented iso-C16:0 (11.0%), anteiso-C17:0 (10.4%) and C18:0 (5.2%). Based on data presented here, strain 11aii⊺ is considered to represent a novel genus and species, for which the name Haloargentinum marplatensis gen. nov. sp. nov. is proposed with the strain 11aii⊺ as type strain.Fil: Perez, Silvina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; ArgentinaFil: Gomila, Margarita. Universitat de les Illes Balears; EspañaFil: Murialdo, Silvia Elena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Ingeniería Bioquímica; ArgentinaFil: Ameztoy, Irene Mabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; ArgentinaFil: Gonzalez Escalona, Narjol. Center For Food Safety And Applied Nutrition; Estados UnidosFil: Ramirez, Elida Elvia. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; ArgentinaFil: Yeannes, Maria Isabel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ingeniería. Departamento de Ingeniería Química. Grupo de Investigación en Preservación y Calidad de Alimentos; Argentin

Enrichment and characterization of a bilge microbial consortium with oil in water-emulsions breaking ability for oily wastewater treatment

Oily bilge wastewater is one of the main sources of hydrocarbons pollution in marine environments due to accidental or clandestine discharges. The main technical challenge for its effective treatment is the presence of stable oil-in-water (O/W) emulsions. In this work we are reporting an enriched microbial consortium from bilge wastewater with remarkable ability to demulsify oil in water emulsions. The consortium showed emulsion-breaking ratios up to 72.6% in the exponential growth phase, while the values range from 11.9 to 8.5% in stationary phase. A positive association was observed between demulsifying ability and microbial adhesion to hydrocarbons, as well as between cell concentration and demulsifying ability. Also, an interesting ability to demulsify under different temperatures, conditions of agitation, and bilge emulsions from different vessels was observed. The Bacterial and Archaeal composition was analyzed by 16S rRNA gene amplicon lllumina sequencing analyses, revealing an assemblage composed of bacterial types highly related to well characterized bacterial isolates and also to non-yet cultured bacterial types previously detected in marine and sediment samples. Hydrocarbonoclastic microbial types such as Marinobacter, Flavobacteriaceae, Alcanivorax and Gammaproteobacteria PYR10d3 were found in high relative abundance (27.0%– 11.1%) and types of marine oligotrophs and surfactant degraders such as Thallasospira, Parvibaculum, Novospirillum, Shewanella algae, and Opitutae were in a group of middle predominance (1.7–3.5%). The microbial consortium reported has promising potential for the biological demulsification of bilge wastewater and other oily wastewaters

Discrimination of motile bacteria from filamentous fungi using dynamic speckle

We present a dynamic laser speckle method to easily discriminate filamentous fungi from motile bacteria in soft surfaces, such as agar plate. The method allows the detection and discrimination between fungi and bacteria faster than with conventional techniques. The new procedure could be straightforwardly extended to different micro-organisms, as well as applied to biological and biomedical research, infected tissues analysis, and hospital water and wastewaters studies