Browsing by Author "Cespedes, R"

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    Characterization of a bacterial consortium degrading the lignin model compound vanillyl-beta-D-glucopyranoside
    (1997) Cespedes, R; Gonzalez, B; Vicuna, R
    Aryl-beta-D-glycosides have been described as intermediates in lignin biodegradation. The catabolism of this kind of compounds has been poorly studied. In this work, the isolation and initial characterization of a bacterial consortium degrading vanillyl-beta-D-glucopyranoside is reported. The consortium is able to grow on and completely degrade the dimer vanillyl-beta-D-glucopyranoside. The consortium is composed of three microorganisms: strain 2.1 is closely related to Chryseomonas luteola; strain 2.2, identified as Moraxella pheylpyruvica and strain 2.3, preliminary identified as Pseudomonas spp. Complete degradation of the glycoside required strains 2.1 and 2.2, although only strain 2.1 was able to cleave the aryl-glycoside linkage. Oxidation of vanillyl alcohol, one product of the aryl-glycoside cleaving reaction, to the respective acid was carried out by strain 2.2. Vanillic acid was used as growth substrate by strains 2.2 and 2.3. Strain 2.1 can grow on other aryl-P-glycosides, accumulating the aryl moiety in the culture. P-Glucosidase present in strain 2.1 is probably the key enzyme in the catabolism of aryl-glycosides by this consortium.
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    Degradation of chlorophenols by Alcaligenes eutrophus JMP134(pJP4) in bleached kraft mill effluent
    (1997) Valenzuela, J; Bumann, U; Cespedes, R; Padilla, L; Gonzalez, B
    The ability of Alcaligenes eutrophus JMP134(pJP4) to degrade 2,4-dichlorophenoxyacetic acid, 2,4,6-trichlorophenol, and other chlorophenols in a bleached kraft mill effluent was studied. The efficiency of degradation and the survival of strain JMP134 and indigenous microorganisms in short-term batch or long-term semicontinuous incubations performed in microcosms were assessed. After 6 days of incubation, 2,4-dichlorophenoxyacetate (400 ppm) or 2,il,6-trichlorophenol (40 to 100 ppm) were extensively degraded (70 to 100%). In short-term batch incubations, indigenous microorganisms were unable to degrade such of compounds. Degradation of 2,4,6-trichlorophenol by strain JMP134 was significantly lower at 200 to 400 ppm of compound. This strain was also able to degrade 2,4-dichlorophenoxyacetate, 2,4,6-trichlorophenol, 4-chlorophenol, and 2,4,5-trichlorophenol when bleached Kraft mill effluent was amended with mixtures of these compounds. On the other hand, the chlorophenol concentration and the indigenous microorganisms inhibited the growth and survival of the strain in short-term incubations. In long-term (>1-month) incubations, strain JMP134 was unable to maintain a large, stable population, although extensive 2,4,6-trichlorophenol degradation was still observed. The latter is probably due to acclimation of the indigenous microorganisms to degrade 2,4,6-trichlorophenol. Acclimation was observed only in long-term, semicontinuous microcosms.