RESUMEN
ABSTRACT: The scope of the present study was to assess the spoilage potential of different Alicyclobacillus spp. in commercial pasteurized (ambient-stable) plant-based dairy beverages mixed with fruit juices at different inoculation levels and storage temperatures. Different products (coconut and berry [CB]; almond, mango, and passionfruit [AMP]; and oat, strawberry, and banana [OSB]) were inoculated with 10 or 2 × 103 spores per mL of either Alicyclobacillus acidoterrestris, Alicyclobacillus fastidiosus, or Alicyclobacillus acidocaldarius strain composites, whereas noninoculated samples served as controls. Samples inoculated with A. acidoterrestris and A. fastidiosus were stored at 30 and 45°C, whereas A. acidocaldarius storage took place at 50°C for 240 days. Gas composition, Alicyclobacillus spp. populations, total viable counts, pH, water activity, color, and guaiacol off-taste were monitored. CB and AMP supported growth of A. acidoterrestris and A. fastidiosus, reaching populations of 4.0 to 5.0 log CFU/mL. In OSB, populations of A. fastidiosus remained close to the initial inoculation levels during storage at 30°C, whereas at 45°C, the populations declined <1 CFU/mL. A. acidocaldarius growth was supported in CB samples, but not in AMP and OSB samples, reaching ca. 3.0 log CFU/mL at 50°C, regardless of initial inoculum size. Total color change was increased during storage; however, the instrumentally recorded color changes were not macroscopically visible. Spoilage in terms of guaiacol off-taste was identified only in CB and AMP samples inoculated with A. acidoterrestris after 60 days at 30 and 45°C. The increased popularity of these products along with the scarcity of existing literature related to their spoilage by Alicyclobacillus spp., render the contribution of the findings and data of present study critical for assessing the significance of Alicyclobacillus spp. as a potential spoilage hazard in these products and for assisting in the design and implementation of effective mitigation strategies by the beverage industry.
Asunto(s)
Alicyclobacillus , Bebidas , Microbiología de Alimentos , Frutas , Jugos de Frutas y Vegetales , Esporas BacterianasRESUMEN
204 bacterial isolates from four Greek refinery sludge deposition sites were investigated for the presence of nahH and alkJ genes encoding key enzymes of both aromatic and aliphatic hydrocarbon degradation pathways by PCR and DNA hybridisation. Members of Pseudomonas, Acinetobacter, Bacillus, Rhodococcus and Arthrobacter play important role in bioremediation processes in sandy/loam soil contaminated with oil and nahH and alkJ genes were present in the 73% of the isolates. Consortia of bacterial isolates that were used for biodegradation of aliphatic and aromatic hydrocarbons in crude oil using liquid cultures exhibited rates from 35% to 48% within 10 days of incubation.
Asunto(s)
Oxidorreductasas de Alcohol/genética , Bacterias Aerobias/enzimología , Biodegradación Ambiental , Catecol 2,3-Dioxigenasa/genética , Petróleo , Microbiología del Suelo , Contaminantes del Suelo/metabolismo , Acinetobacter/enzimología , Acinetobacter/genética , Acinetobacter/aislamiento & purificación , Oxidorreductasas de Alcohol/metabolismo , Arthrobacter/enzimología , Arthrobacter/genética , Arthrobacter/aislamiento & purificación , Bacillus/enzimología , Bacillus/genética , Bacillus/aislamiento & purificación , Bacterias Aerobias/genética , Bacterias Aerobias/aislamiento & purificación , Catecol 2,3-Dioxigenasa/metabolismo , ADN Ribosómico , Contaminación Ambiental , Hidrocarburos Aromáticos/metabolismo , Hibridación de Ácido Nucleico , Reacción en Cadena de la Polimerasa , Pseudomonas/enzimología , Pseudomonas/genética , Pseudomonas/aislamiento & purificación , Rhodococcus/enzimología , Rhodococcus/genética , Rhodococcus/aislamiento & purificaciónRESUMEN
Three new members of the fluostatin family, fluostatins C-E, were discovered in a culture filtrate extract of strain Acta 1383 during an HPLC screening program. The producing strain belongs to the genus Streptomyces and is closely related to type strains classified in the Streptomyces lavendulae 16S rRNA subclade. Fluostatins are named by their characteristic fluorenone chromophore. Fluostatin C shows moderate activity against selected human tumor cell lines.
Asunto(s)
Antineoplásicos/aislamiento & purificación , Fluorenos/aislamiento & purificación , Streptomyces/química , Antineoplásicos/química , Antineoplásicos/farmacología , Línea Celular Tumoral , Fluorenos/química , Fluorenos/farmacología , Humanos , Estructura Molecular , Espectrometría de Masa por Ionización de Electrospray , Espectrofotometría UltravioletaRESUMEN
One-hundred and fifty different thermophilic bacteria isolated from a volcanic island were screened for detection of an alkane hydroxylase gene using degenerated primers developed to amplify genes related to the Pseudomonas putida and Pseudomonas oleovorans alkane hydroxylases. Ten isolates carrying the alkJ gene were further characterized by 16s rDNA gene sequencing. Nine out of ten isolates were phylogenetically affiliated with Geobacillus species and one isolate with Bacillus species. These isolates were able to grow in liquid cultures with crude oil as the sole carbon source and were found to degrade long chain crude oil alkanes in a range between 46.64% and 87.68%. Results indicated that indigenous thermophilic hydrocarbon degraders of Bacillus and Geobacillus species are of special significance as they could be efficiently used for bioremediation of oil-polluted soil and composting processes.
