-
[show abstract]
[hide abstract]
ABSTRACT: To evaluate the production and stability of laccases by Pleurotus ostreatus in liquid co-cultures with Trichoderma viride as a function of infection time and agitation rate.
Pleurotus ostreatus cultures were infected with T. viride spores at 30 and 48 h. Maximal laccase volumetric activity was seen after 48 h (control cultures) or 72 h (co-cultures) of cultivation time. Only the cultures infected at 30 h showed an increased laccase volumetric activity compared to control cultures. After maximal laccase volumetric activity value was reached, a sharp decrease in it was observed in control cultures. Co-cultures exhibited a comparatively lower loss of activity. The influence of P. ostreatus and/or T. viride on the stability of laccase volumetric activity and isoenzyme pattern was evaluated. Trichoderma viride induced changes in the laccase isoenzyme pattern. Agitated cultures increased biomass growth and specific productivity threefold and sevenfold, respectively, to the static cultures.
The laccase volumetric activity is very likely the result of the balance between biosynthesis and degradation/biotransformation rates occurring during the cultures. The individual presence of P. ostreatus or T. viride in the culture negatively affected the volumetric laccase activity.
The evaluation of culture parameters that could influence Trichoderma-basidomycetes interaction and laccase production during submerged fermentation has not been reported. This study showed how laccase production in co-cultures of P. ostreatus and T. viride was influenced by the infection time and agitation/oxygenation conditions.
Journal of Applied Microbiology 08/2009; 108(3):810-7. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: To select Trichoderma strains for enhanced laccase production in Pleurotus ostreatus or Agaricus bisporus cultures.
Laccase production by P. ostreatus and A. bisporus was evaluated in liquid (axenic) and solid (dual cultures) malt extract medium. Oxidation of ABTS, DMP and syringaldazine was evaluated in order to assess the potential of Trichoderma strains to enhance laccase production by basidiomycetes. Selected Pleurotus-Trichoderma interactions yielded higher increases in laccase volumetric activity and an additional laccase isoform was produced. By contrast, Agaricus-Trichoderma interactions lead to smaller increases on laccase volumetric activity, probably as result of repression (or degradation) towards one of the laccases isoforms.
The strains of P. ostreatus and A. bisporus assessed in this work showed good potential as laccase producers. The Trichoderma-mediated biological stimulation of laccase production by P. ostreatus and A. bisporus is relevant in order to develop highly productive processes.
Extracellular laccases from basidiomycetes are produced only in small amounts. It is therefore important to increase process productivity for potential industrial applications. The results from this study enable the selection Trichoderma strains capable of increasing laccase production by P. ostreatus or A. bisporus in dual cultures.
Journal of Applied Microbiology 01/2009; 106(1):249-57. · 2.34 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: We assessed the biodegradation of a typical oily sludge waste (PB401) in Mexico using several regimes of indigenous microbial consortium and relevant bioremediation strategies in slurry-phase system. Abiotic loss of total petroleum hydrocarbons (TPH) in the PB401 was insignificant, and degradation rates under the various treatment conditions ranged between 666.9 and 2168.7 mg kg(-1) day(-1) over a 15 days reaction period, while viable cell count peaked at between log(10)5.7 and log(10)7.4 cfu g(-1). Biostimulation with a commercial fertilizer resulted in 24% biodegradation of the TPH in the oily waste and a corresponding peak cell density of log(10)7.4 cfu g(-1). Addition of non-indigenous adapted consortium did not appear to enhance the removal of TPH from the oily waste. It would appear that the complexities of the components of the alkylaromatic fraction of the waste limited biodegradation rate even in a slurry system.
Chemosphere 02/2008; 70(4):737-44. · 3.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Experiments were carried out to evaluate the use of some agroindustrial wastes as supports in solid state cultures for the biodegradation of crude oil Maya in static column reactors over 15-20 days periods. Spent compost and cane bagasse wastes showed superior qualities over peat moss waste as support candidates with the advantage that they contain appreciable densities of autochthonous microorganisms in the order of 10(2) cfu g(-1). Mercuric chloride (2%) was able to completely inhibit growth of these microfloras. Biodegradation was enhanced in the presence of the IMP consortium and highest when microflora from cane bagasse only was the bioaugmentation partner (180.7 mg kg(-1) day(-1)). Combination of these waste materials (3:1 ratio, respectively) was observed to significantly biodegrade the crude oil by approximately 40% in 15 days from an initial concentration of 10,000 mg kg(-1) with a four order of magnitude increase in microbial density during this period. Spent compost and cane bagasse wastes are veritable solid support candidates for use in the biodegradation of crude oil polluted systems.
Chemosphere 06/2007; 68(5):848-55. · 3.21 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The efficiencies of several biological strategies as potential enhancers for removal of polycyclic aromatic hydrocarbons (PAHs) were evaluated by analyzing benzo[a]pyrene depletion at three different concentrations: viz. 25, 50 and 75 mg L−1. The effect of using individual cultures of different fungal or bacterial strains and combinations of the two to obtain defined fungal–bacterial co-cultures on benzo[a]pyrene removal was evaluated. The microbial test strains included Aspergillus niger, Penicillium Trichoderma harzianum, Saccharomyces cerevisiae, Serratia marcescens, Bacillus mycoides and Pseudomonas sp. Depletion profiles under various treatment conditions ranged from 9 to 84% and from 1 to 35% for fungal and bacterial cultures, respectively. The highest removal rate in all the treatments was achieved consistently by the fungal strains, and in general, pure cultures of both bacteria and fungi were found to be more sensitive to variations in benzo[a]pyrene concentration. When different defined fungal–bacterial co-cultures were tested, benzo[a]pyrene removal was higher (65%, 50 mg L−1) with the Penicillium sp./S. marcescens co-culture. Our results show that the use of fungal cultures was more effective for benzo[a]pyrene degradation than the use of bacterial cultures even when the concentration was increased three-fold. Moreover, it shows that the use of a defined fungal–bacterial co-culture can enhance benzo[a]pyrene biodegradation.
International Biodeterioration & Biodegradation.
-
[show abstract]
[hide abstract]
ABSTRACT: We assessed the biodegradation of a typical oily sludge waste (PB401) in Mexico using several regimes of indigenous microbial consortium and relevant bioremediation strategies in slurry-phase system. Abiotic loss of total petroleum hydrocarbons (TPH) in the PB401 was insignificant, and degradation rates under the various treatment conditions ranged between 666.9 and 2168.7 mg kg−1 day−1 over a 15 days reaction period, while viable cell count peaked at between log10 5.7 and log10 7.4 cfu g−1. Biostimulation with a commercial fertilizer resulted in 24% biodegradation of the TPH in the oily waste and a corresponding peak cell density of log10 7.4 cfu g−1. Addition of non-indigenous adapted consortium did not appear to enhance the removal of TPH from the oily waste. It would appear that the complexities of the components of the alkylaromatic fraction of the waste limited biodegradation rate even in a slurry system.
Chemosphere.
