No abstract

Purpose This paper aims to evaluate the bioremediation [chemical oxygen demand (COD) and color removal] of the effluent from the cardboard recycling industry in Yazd, central province of Iran, using mixed fungal culture. Design/methodology/approach First, the effluent samples from the cardboard recycling industry were cultured on potato dextrose agar medium to isolate native fungal colonies. The grown colonies were then identified using morphological macroscopic and microscopic characteristics to choose the dominant fungi for bioremediations. The mixed cultures of Aspergillus niger, Aspergillus flavus and Penicillium digitatum were finally used for bioremediation experiments of the cardboard recycling industry. A suspension containing 1 × 106 CFU/ml of fungal spores was prepared from each fungus, separately and their homogenous mixture. Sewage samples were prepared and sterilized and used at 25%, 50% and 90% dilutions and pH levels of 5, 7 and 8 for bioremediation tests using mixed fungal spores. Following that, 10 ml of the mixed fungal spores were inoculated into the samples for decolorization and COD removal and incubated for 10 days at 30°C. The amount of COD removal and decolorization were measured before incubation and after 3, 6 and 10 days of inoculation. In this research, the color was measured by American Dye Manufacturer Institute and COD by the closed reflux method. The results of the present study were analyzed using SPSS 21 statistical software and one-way ANOVA tests at p-value < 0.05. Findings The results of this research showed that the mean decolorization by mixed fungal culture over 10 days at pH levels of 5, 7 and 8 were 44.40%, 45.00% and 36.84%, respectively, and the mean COD removal efficiency was 71.59%, 73.54% and 16.55%, respectively. Moreover, the mean decolorization at dilutions of 25%, 50% and 90% were 45.00%, 31.93% and 30.53%, respectively, and the mean COD removal efficiency was 73.54%, 62.38% and 34.93%, respectively. Therefore, the maximal COD removal and decolorization efficiency was obtained at dilution of 25% and pH 7. Originality/value Given that limited studies have been conducted on bioremediation of the effluent from the cardboard recycling industry using fungal species, this research could provide useful information on the physicochemical properties of the effluent in this industry.

Introduction: By increasing the amount and diversity of bio-environmental wastewater pollutants, it is essential to be controlled and planed the environmental contaminants to eliminate or minimize. Cardboard recycling industry wastewater has the potential of environmental pollution; it is contaminated with various fungal species that may be effective in the decomposition and removal of pollutants. The aim of this study was the isolation and identification of native fungal species that decontaminate organic pollutants in the cardboard recycling industry wastewaters. Methods: In this study, which is a descriptive study, samples were randomly taken from different area of wastewater of cardboard recycling industry. Samples were cultured on Saboraud dextrose agar medium for isolation of probable fungal species, which decomposers of wastewater. The isolated fungal colonies were enumerated and purified based on morphological characteristics and microscopic analyzing as far as possible. Results: The average count of the total number of fungi species in wastewater of cardboard recycling industry was 2.5×102 CFU/ml of these 2.1×101 were saprophytic fungi. The most prevalent fungal species were identificated from the wastewater include Aspergillus niger, Aspergillus flavus, Penicillum, Geotrichum, Mucor, Drechselera, Paecillomyces, Alternaria, Fusarium and Absidia. The highest frequency of fungal species Aspergillus nige, Aspergillus flavus and Penicillum were 30.89%, 22.76% and 14.63% respectively. Conclusion: It seems that native fungi isolated from the cardboard recycling industry wastewater in this study are from fungi that have the potential for bioremediation of wastewater contaminants based on scientific literature and can be used for evaluating of their ability to decompose wastewater from this industry.