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The degradation of methylene blue (MB) by semi-solid-state fermentation of agricultural residues rice straw with Phanerochaete chrysosporium and the reutilization of fermented residues was investigated. A maximum decolorization of 84.8% for an initial dye concentration of 0.4 g/L was observed at the optimal operating conditions (temperature 35 °C, pH 5). As compared to the previous results obtained using synthetic materials as substrate, the results in the present study revealed an excellent performance of the bioreactor in decolorizing the wastewater containing MB, which is due to this type of cultivation reproducing the natural living conditions of the white rot fungi. Among the two ligninolytic enzymes that are responsible to the decolorization, manganese peroxidase (MnP) activity was found better correlated with decoloration percentage. Our results also provide a first step to recycling the fermented residues for the removal of MB from aqueous solutions, the maximum adsorption capacity of the fermented residues reached 51.4 mg/g. [ABSTRACT FROM AUTHOR]

Highlights: [•] Low concentration of Pb2+ could enhance the production of OH. [•] OH production declined when the initial Pb2+ concentration reached 400mgkg−1. [•] A remarkable correlation was found between OH content and oxalate concentration. [•] No obvious relationship was found between OH content and lignin degradation rate. [ABSTRACT FROM AUTHOR]

Abstract: The objective of this study was to assess the response of carbon utilization profiles to addition of ligninolytic enzymes and the relationship between the carbon utilization and lignin degradation. Ligninolytic enzymes were added into the initial composting materials as treatment, and the inactive ligninolytic enzymes were added into the composting materials as control. The results showed that the treatment increased the degradation ratio of lignin and hemicellulose by 5.24% and 11.74%, respectively (P <0.05), comparing to the result of control. Carbon utilization (measured by Biolog EocPlate™) revealed that, in the treatment, average well-color development (AWCD) of amino acids was significantly enhanced after day 6 (P <0.05), while AWCD of carboxylic acids and polymers were increased after day 15. Principal component analysis confirmed the differentiation of the treatment and the control. The correlations between the lignin degradation and the Biolog indexes indicated that the presence of ligniolytic enzymes could enhance the activity of microorganisms. [Copyright &y& Elsevier]