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The optimization of ligninolytic enzyme (LE) activities in a novel fungal co-culture between Pycnoporus sanguineus and Beauveria brongniartii were studied using a Plackett-Burman experimental design (PBED) and a central composite design (CCD). In addition, H2O2 role was analyzed. Laccase (EC. 1.10.3.2) and MnP (EC 1.11.1.14) activities of P. sanguineus increased 6.0- and 2.3-fold, respectively, in the co-culture with B. brongniartii. The H2O2 content was higher in the co-culture (0.33-7.12-fold) than in the P. sanguineus monoculture. The PBED revealed that yeast extract (YE), FeSO4, and inoculum amount were significant factors for laccase and MnP activities and H2O2 production in the co-culture, which increased by 8.2-, 5.2- and 1.03-fold, respectively. The YE and FeSO4 were studied using a CCD to optimize the studied response variables. Laccase activity was enhanced 1.5-fold by CCD, the optimal amount of YE was 0.366 g L−1. Quadratic term of FeSO4 modulated MnP activity and was associated with a 4.28-fold increase compared to the PBED. Both YE and its quadratic term significantly affected H2O2 production; however, the CCD did not enable an increase in H2O2 production. Pearson correlation indicated an increase in laccase (r2=0.4411, p = 0.0436) and MnP (r2=0.5186, p = 0.0198) activities following increases in H2O2 in the co-culture system. [ABSTRACT FROM AUTHOR]

This investigation was undertaken to determine the atrazine degradation by fungal enzyme extracts (FEEs) in a clay-loam soil microcosm contaminated at field application rate (5 μg g−1) and to study the influence of different soil microcosm conditions, including the effect of soil sterilization, water holding capacity, soil pH and type of FEEs used in atrazine degradation through a 24factorial experimental design. TheTrametes maxima–Paecilomyces carneusco-culture extract contained more laccase activity and hydrogen peroxide (H2O2) content (laccase = 18956.0 U mg protein−1, H2O2= 6.2 mg L−1) than theT. maximamonoculture extract (laccase = 12866.7 U mg protein−1, H2O2= 4.0 mg L−1). Both extracts were able to degrade atrazine at 100%; however, theT. maximamonoculture extract (0.32 h) achieved a lower half-degradation time than its co-culture withP. carneus(1.2 h). The FEE type (p= 0.03) and soil pH (p= 0.01) significantly affected atrazine degradation. The best degradation rate was achieved by theT. maximamonoculture extract in an acid soil (pH = 4.86). This study demonstrated that both the monoculture extracts of the native strainT. maximaand its co-culture withP. carneuscan efficiently and quickly degrade atrazine in clay-loam soils. [ABSTRACT FROM AUTHOR]

Background: In the industrial biotechnology, ligninolytic enzymes are produced by single fungal strains. Experimental evidence suggests that co-culture of ligninolytic fungi and filamentous microfungi results in an increase laccase activity. In this topic, only the ascomycete Trichoderma spp. has been studied broadly. However, fungal ligninolytic-filamentous microfungi biodiversity interaction in nature is abundant and poorly studied. The enhancement of laccase and manganese peroxidase (MnP) activities of Trametes maxima as a function of time inoculation of Paecilomyces carneus and under several culture conditions using Plackett-Burman experimental design (PBED) were investigated. Results: The highest increases of laccase (12,382.5 U/mg protein) and MnP (564.1 U/mg protein) activities were seen in co-cultures I3 and I5, respectively, both at 10 d after inoculation. This level of activity was significantly different from the enzyme activity in non-inoculated T. maxima (4881.0 U/mg protein and 291.8 U/mg protein for laccase and MnP, respectively). PBED results showed that laccase was increased (P b 0.05) by high levels of glucose, (NH4)2SO4 and MnSO4 and low levels of KH2PO4, FeSO4 and inoculum (P < 0.05). In addition, MnP activity was increased (P < 0.05) by high yeast extract, MgSO4, CaCl2 and MnSO4 concentrations. Conclusions: Interaction between indigenous fungi: T. maxima-P. carneus improves laccase and MnP activities. The inoculation time of P. carneus on T. maxima plays an important role in the laccase and MnP enhancement. The nutritional requirements for enzyme improvement in a co-culture system are different from those required for a monoculture system. [ABSTRACT FROM AUTHOR]