RESUMO
AIMS: A microbe-colonized gas-liquid foam formulation has been previously shown to provide enhanced biodegradation capabilities in soil microcosms. The present study considers the reservoir properties of this foam and how this affects hydrocarbon degradation rates. METHODS AND RESULTS: Oxygen solubility in protein hydrolysate solutions draining from aerated and oxygenated foams was measured. The suitability of oxygenated foam to enhance the degradation of n-hexadecane in soil microcosms was assessed. Sorption of bacterial isolates at the gas-liquid interface was also investigated using a range of microscopy techniques. CONCLUSIONS: Oxygenated bioactive foam enhanced biodegradation rates by improving oxygen availability and transfer. Biodegradation of n-hexadecane was also stimulated by the protein hydrolysate used and by the inclusion of known bacterial hydrocarbon-degrading bacteria. The interaction of bacteria with the gas-liquid interface was shown to be a significant factor governing the drainage of the bacteria from the bioactive foam. SIGNIFICANCE AND IMPACT OF THE STUDY: Protein hydrolysate-based bioactive foam may be a suitable treatment technology to enhance the biodegradation of petroleum hydrocarbons in soil.
Assuntos
Bactérias/metabolismo , Hidrocarbonetos/metabolismo , Oxigênio/metabolismo , Petróleo , Hidrolisados de Proteína/metabolismo , Alcanos/metabolismo , Biodegradação Ambiental , Biotecnologia , Meios de Cultura , Interações Hidrofóbicas e Hidrofílicas , Poluentes do Solo/metabolismoRESUMO
Aspergillus flavus grown on 2,6-dimethoxyphenol as sole carbon source produced tetramethoxy-p-dibenzoquinone by a free radical mechanism. The product was identified by H-nmr and ms. Scanning electron microscopy and light microscopy were used to follow the growth of mycelia and the attachment of crystals to the mycelial surfaces. Formation of dimer was inhibited by the presence of glucose in the medium.
Assuntos
Aspergillus flavus/metabolismo , Pirogalol/análogos & derivados , Aspergillus flavus/crescimento & desenvolvimento , Aspergillus flavus/ultraestrutura , Microscopia Eletrônica de Varredura , Pirogalol/metabolismoRESUMO
Spoilage fungi of the genus Aspergillus were detected and estimated in 24 h by a modification of the Most Probable Number method. The method is based on the production of pectolytic enzymes in a medium supplemented with pectin. These enzymes hydrolyse the bonds of pectin to produce galacturonic acid, causing a fall in pH and an indicator present in the medium changes colour, thus allowing tubes to be scored as positive. Results obtained by this method were generally higher than those obtained by traditional plate counts.
Assuntos
Aspergillus/isolamento & purificação , Microbiologia de Alimentos , Técnicas Microbiológicas , Pectinas/metabolismo , Aspergillus/enzimologiaRESUMO
Mixed cultures of viable spores of fungi of the Aspergillaceae were determined rapidly by gas-liquid chromatography of the methanol released from pectin by the enzyme pectinesterase. Results obtained in 19 h were comparable with plate counts taking 48 h. Attempts to count spoilage years using this method were not successful.
Assuntos
Microbiologia de Alimentos , Fungos/metabolismo , Metanol/análise , Aspergillus/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Cromatografia Gasosa , Grão Comestível , Frutas , Pectinas/metabolismo , Penicillium/metabolismoRESUMO
A number of strains purporting to belong to the species Sporothrix schenckii were examined for their fatty acid content. The majority of the strains were isolated from cases of sporotrichosis. Two strains were reputedly saprophytic. In all cases except the two saprophytic ones the major fatty acid was a C18 diene. Considerable amounts of palmitic acid and C18 monoene were found in all strains.