RESUMO
A strategy for the detection of aflatoxin B1 using a capacitive biosensor has been studied. The use of proteins for the generation of sites with high specificity against aflatoxin B1 are produced via bioimprinting. This technique has become a tool for the detection of aflatoxin B1 using a capacitive biosensor. The results demonstrate the ability to generate specific interactions with aflatoxin B1 with a linear relation between signals registered and log concentration of the target aflatoxin in the concentration range of 3.2 × 10-6 to 3.2 × 10-9 M when using ovalbumin as framework for the bioimprinting.
RESUMO
A capacitive biosensor was used for detection of aflatoxin B1. Two different methods for cleaning gold electrodes were evaluated using cyclic voltammetry in the presence of ferricyanide as redox couple. The methods involve use of a sequence of cleaning steps avoiding the use of Piranha solution and plasma cleaner. Anti-aflatoxin B1 was immobilized on self-assembled monolayers (SAM). The immune-capacitive biosensor is able to detect aflatoxin B1 concentrations in a linear range of 3.2 × 10-12 M to 3.2 × 10-9 M when thiourea was used to form the SAM; 3.2 × 10-9 M to 3.2 × 10-7 M when thioctic acid was used. When the gold surface was isolated with tyramine-electropolymerization linear ranges of 3.2 × 10-13 M to 3.2 × 10-7 M and 3.2 × 10-9 M to 3.2 × 10-7 M where obtained, respectively. The results obtained show the difference in linear range, limit of detection, and limit of quantification when different self-assembled monolayers are used for aflatoxin B1 detection.
RESUMO
A novel moderately thermophilic, anaerobic, ethanol-producing bacterial strain, 45B(T), was isolated from a mixed sediment water sample collected from a hot spring at Potosi, Bolivia. The cells were straight to slightly curved rods approximately 2.5 µm long and 0.5 µm wide. The strain was Gram-stain-variable, spore-forming and monotrichously flagellated. Growth of the strain was observed at 45-65 °C and pH 5.5-8.0, with optima of 60 °C and pH 6.5. The substrates utilized by strain 45B(T) were xylose, cellobiose, glucose, arabinose, sucrose, lactose, maltose, fructose, galactose, mannose, glycerol, xylan, carboxymethylcellulose and yeast extract. The main fermentation product from xylose and cellobiose was ethanol (0.70 and 0.45 g ethanol per gram of consumed sugar, respectively). Acetate, lactate, propionate, carbon dioxide and hydrogen were also produced in minor quantities. 1,3-Propanediol was produced when glycerol-containing medium was supplemented with yeast extract. The major cellular fatty acids were anteiso-C(15:0), C(16:0), iso-C(16:0), C(15:1), iso-C(14:0), C(13:0) and C(14:0). The polar lipids diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an aminoglycolipid and 15 other unidentified lipids were predominant. The DNA G+C content of strain 45B(T) was 32.6 mol%. Phylogenetic analysis based on 16S rRNA gene sequence similarity revealed that strain 45B(T) is located within the Gram-type positive Bacillus-Clostridium branch of the phylogenetic tree. On the basis of morphological and physiological properties and phylogenetic analysis, strain 45B(T) represents a novel species, for which the name Caloramator boliviensis sp. nov. is proposed; the type strain is 45B(T) (=DSM 22065(T)=CCUG 57396(T)).
Assuntos
Bactérias Anaeróbias/classificação , Bactérias Anaeróbias/isolamento & purificação , Etanol/metabolismo , Bactérias Gram-Positivas/classificação , Bactérias Gram-Positivas/isolamento & purificação , Fontes Termais/microbiologia , Bactérias Anaeróbias/genética , Bactérias Anaeróbias/metabolismo , Técnicas de Tipagem Bacteriana , Composição de Bases , Bolívia , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Ácidos Graxos/análise , Fermentação , Bactérias Gram-Positivas/genética , Bactérias Gram-Positivas/metabolismo , Temperatura Alta , Concentração de Íons de Hidrogênio , Microscopia , Dados de Sequência Molecular , Fosfolipídeos/análise , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Esporos Bacterianos/citologiaRESUMO
Three methanogenic biofilm bioreactors were studied to evaluate the performance of three types of carriers. The carrier material were consisted of sisal fibre waste, pumice stone and porous glass beads, and the bioprocess evaluated was the methanogenesis anaerobic digestion of sisal leaf waste leachate. Process performance was investigated by increasing the organic loading rate (OLR) step-wise. The best results were obtained from the bioreactor packed with sisal fibre waste. It had the highest chemical oxygen demand (COD) removal efficiencies in the range of 80-93 percent at OLRs in the range of 2.4-25 g COD L-1d-1. The degradation pattern of volatile fatty acids (VFAs) showed that the degradation of propionate was limiting at higher OLRs. The stable pH and higher partial alkalinity (PA) of the outflow illustrated that packed-bed bioreactors have a good ability to withstand the variations in load and volatile fatty acid concentrations that can occur in a two-stage anaerobic process. In conclusion, sisal fibre waste was shown to be a novel promising biofilm carrier and would work very well in methanogenic biofilm bioreactors treating sisal leaf tissue waste leachate. Furthermore both sisal wastes are available in the neighbourhood of sisal industries, which makes anaerobic digestion scale up at sisal factory level feasible and cost-effective.
Assuntos
Biocombustíveis , Biofilmes , Percolação , Folhas de Planta , Gerenciamento de Resíduos , Biodegradação Ambiental , Resíduos IndustriaisRESUMO
Biological production of hydrogen sulfide (H(2)S) using sulfate-reducing bacteria (SRB) has important potential within environmental biotechnology. The aim of this work was to study the possibility of using SRB for the treatment of an acid mine drainage (AMD) at bench-scale. This process involved three stages: the optimization of H(2)S production through the utilization of total volatile fatty acids (TVFAs) by SRB, the establishment of a biofilm reactor for sulfide production, and the precipitation of metals by using the biologically produced H(2)S. The substrates used for TVFAs production consisted of papaya, apple and banana. The H(2)S produced from the degradation of TVFAs was utilized for the precipitation of a metal-contaminated effluent collected from Bolivar mine (Oruro, Bolivia). The maximum concentration of H(2)S obtained was approximately 16mM. Removal efficiencies of ca. 100% for copper, above 94% for zinc, and above 92% for lead were achieved.
Assuntos
Bactérias/metabolismo , Biofilmes , Reatores Biológicos , Ácidos Graxos/metabolismo , Sulfeto de Hidrogênio/metabolismo , Metais Pesados/metabolismo , Poluentes Químicos da Água/metabolismo , Poluição da Água/prevenção & controle , Biotecnologia/métodos , Bolívia , Frutas/química , Concentração de Íons de Hidrogênio , Mineração , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/genéticaRESUMO
Degradation of toxaphene in soil from both newly contaminated (from Sweden) and aged spills (from Nicaragua) were studied. The newly contaminated soil contained approximately 11 mg kg(-1) toxaphene while the aged Nicaraguan soil contained approximately 100 mg kg(-1). Degradation was studied in anaerobic bioreactors, some of which were supplied with lactic acid and others with Triton X-114. In this study we found that the lower isomers Parlar 11, 12 were degraded while the concentration of isomer Parlar 15 increased. This supported an earlier evaluation which indicated that less chlorinated isomers are formed from more heavily isomers. Lactic acid when added to the soil, interfere with the degradation of toxaphene. Lactic acid was added; several isomers appeared to degrade rather slowly in newly contaminated Swedish soil. The Swedish soil, without any external carbon source, showed the slowest degradation rate of all the compounds studied. When Triton X-114 at 0.4 mM was added, the degradation rate of the compounds increased. This study illustrates that biodegradation of toxaphene is a complex process and several parameters have to be taken into consideration. Degradation of persistent pollutants in the environment using biotechnology is dependent on bioavailability, carbon sources and formation of metabolites.
Assuntos
Poluentes do Solo/metabolismo , Toxafeno/metabolismo , Anaerobiose , Biodegradação Ambiental , Isomerismo , Ácido Láctico/metabolismo , Nicarágua , Octoxinol , Polietilenoglicóis/metabolismo , Suécia , Fatores de Tempo , Toxafeno/químicaRESUMO
De un tamizaje realizado entre las cepas fúngicas que conforman el cepario del IIFB, como parte del proyecto Biodiversidad Microbiana del Programa UMSA-Asdi/ Sarec que se desarrolla en forma conjunta con eldepartamento de Biotecnología Ambiental de la Universidad de Lund, se seleccionaron 6 cepas con actividad biológica contra Botrytis cinerea y Alternaria solani, estas fueron clasificadas, a nivel de género, comoTrichoderma sp., (12-QD), Cephalosporium sp., (8-QD),Aspergillus sp., (24-QD), Rizophus sp., (291-QD), Wardomyces sp., (178-QD), Streptomyces sp., (22-QD).Estos microorganismos saprofiticos fueron sometidos a condiciones de fermentación, en estanco y agitado. Losfiltrados de los fermentos que presentaron mayor actividad fueron los obtenidos de Trichoderma sp con un 79,9% de actividad frente a Botrytis cinerea y 61% frente a Alternaria solani. Se observó que la actividadbiológica esta relacionada con la génesis de pigmentos amarillos
Assuntos
Aspergillus/isolamento & purificação , Fermento Químico , Trichoderma/isolamento & purificaçãoRESUMO
Enterobacter sp. strain D1 is a facultative anaerobic, Gram-negative heterotrophic bacterium isolated from toxaphene-contaminated soil. This organism was identified and characterized through phylogenetic and taxonomic studies. Based on 16S rDNA analysis, the strain D1 was clustered closely with the species Enterobacter cloacae subsp. dissolvens (LMG 2683) and E. cloacae (ATCC 13047T). Strain D1 resembled these E. cloacae strains with respect to various biochemical and nutritional characteristics, but also exhibited differences. Moreover, strain D1 is able to grow and survive with toxaphene supplied in the medium in the range 3-96 mg/L. Amongst the chemical components of toxaphene, octachlorocamphenes, nonachlorobornanes and decachlorobornanes were seen to be rapidly metabolized, although levels of hexachlorocamphenes and heptachlorobornanes were found to be slowly degraded, and subsequently accumulated during the last stage of the cultivation.
Assuntos
Enterobacter cloacae/classificação , Microbiologia do Solo , Toxafeno/metabolismo , Biodegradação Ambiental , DNA Ribossômico/análise , Enterobacter cloacae/metabolismo , Nicarágua , Filogenia , Poluentes do Solo/metabolismoRESUMO
Strain LBB3(T) isolated from Bogoria soda lake in Kenya is an alkaliphilic, Gram-positive, strictly aerobic, non-motile, spore-forming bacterium. It was identified as a member of the genus Bacillus on the basis of phenotypic and phylogenetic analyses. The organism grows optimally at 37 degrees C and pH 10. The G+C content of the genomic DNA is 37.5 mol%. 16S rRNA gene sequence analysis showed 95 and 96 % sequence similarity with Bacillus pseudofirmus (DSM 8715(T)) and Bacillus alcalophilus (DSM 485(T)), respectively. Furthermore, DNA-DNA hybridization against these two Bacillus species showed 39.0 and 55.5 % similarity, respectively. Based on our observations, strain LBB3(T) is proposed to represent a novel species of the genus Bacillus, for which the name Bacillus bogoriensis sp. nov. is proposed. The type strain of B. bogoriensis is LBB3(T) (=ATCC BAA-922(T)=LMG 22234(T)).
Assuntos
Bacillus/classificação , Água Doce/microbiologia , Cloreto de Sódio , Bacillus/genética , Bacillus/crescimento & desenvolvimento , Bacillus/isolamento & purificação , Composição de Bases , DNA Bacteriano/análise , DNA Ribossômico/análise , Genes de RNAr , Concentração de Íons de Hidrogênio , Quênia , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Fenótipo , Filogenia , RNA Ribossômico 16S/genética , Análise de Sequência de DNARESUMO
A moderately halophilic, aerobic, motile, Gram-negative, rod-shaped bacterium (strain LV4(T)) was isolated from saline soil around the lake Laguna Verde in the Bolivian Andes. The organism is a heterotroph, able to utilize various carbohydrates as a carbon source. It showed tryptophan deaminase, oxidase and catalase activity, but was unable to produce indole or H(2)S; nitrate was not reduced. The G+C content of the genomic DNA was 56.1 mol%. The pH range for growth was 5-10, temperature range was 0-45 degrees C and the range of NaCl concentrations was 0-25 % (w/v). On the basis of 16S rRNA gene sequence analysis, strain LV4(T) was found to be closely related to Chromohalobacter canadensis DSM 6769(T) and Pseudomonas beijerinckii DSM 7218(T); however, its DNA-DNA relatedness with these type strains was low. Strain LV4(T) resembled other Chromohalobacter species with respect to various physiological, biochemical and nutritional characteristics but also exhibited differences. Thus, a novel species, Chromohalobacter sarecensis sp. nov., is proposed, with LV4(T) (=CCUG 47987(T)=ATCC BAA-761(T)) as the type strain.
Assuntos
Halomonadaceae/classificação , Halomonadaceae/isolamento & purificação , Microbiologia do Solo , Aminoácido Oxirredutases/análise , Técnicas de Tipagem Bacteriana , Composição de Bases , Bolívia , Metabolismo dos Carboidratos , Catalase/análise , DNA Bacteriano/química , DNA Bacteriano/isolamento & purificação , DNA Ribossômico/química , DNA Ribossômico/isolamento & purificação , Genes de RNAr , Violeta Genciana , Halomonadaceae/citologia , Halomonadaceae/genética , Halomonadaceae/metabolismo , Halomonadaceae/fisiologia , Sulfeto de Hidrogênio/metabolismo , Concentração de Íons de Hidrogênio , Indóis/metabolismo , L-Aminoácido Oxidase , Dados de Sequência Molecular , Movimento , Hibridização de Ácido Nucleico , Oxirredutases/análise , Fenazinas , Filogenia , Pseudomonas/genética , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Solução Salina Hipertônica , Análise de Sequência de DNA , TemperaturaRESUMO
Halomonas boliviensis sp. nov. is proposed for two moderately halophilic, psychrophilic, alkalitolerant bacteria, LC1(T) (=DSM 15516(T)=ATCC BAA-759(T)) and LC2 (=DSM 15517=ATCC BAA-760), both of which were isolated from a soil sample around the lake Laguna Colorada, located at 4300 m above sea level in the south-west region of Bolivia. The bacteria are aerobic, motile, Gram-negative rods that produce colonies with a cream pigment. Moreover, they are heterotrophs that are able to utilize various carbohydrates as carbon sources. The organisms reduce nitrate and show tryptophan deaminase activity. The genomic DNA G+C contents were 51.4 mol% for isolate LC1(T) and 52.6 mol% for isolate LC2. Based on 16S rDNA sequence analysis, isolates LC1(T) and LC2 were identified as members of the genus Halomonas and clustered closely with Halomonas variabilis DSM 3051(T) and Halomonas meridiana DSM 5425(T). However, DNA-DNA relatedness between the new isolates and the closest related Halomonas species was low.