Biodegradation and detoxification of dyes, Malachite green, Nigrosin and Basic fuchsin have been carried out using two fungal isolates Aspergillus niger, and Phanerochaete chrysosporium, isolated from dye effluent soil. Three methods were selected for biodegradation, viz. agar overlay and liquid media methods; stationary and shaking conditions at 25 °C. Aspergillus niger recorded maximum decolorization of the dye Basic fuchsin (81.85%) followed by Nigrosin (77.47%), Malachite green (72.77%) and dye mixture (33.08%) under shaking condition. Whereas, P. chrysosporium recorded decolorization to the maximum with the Nigrosin (90.15%) followed by Basic fuchsin (89.8%), Malachite green (83.25%) and mixture (78.4%). The selected fungal strains performed better under shaking conditions compared to stationary method; moreover the inoculation of fungus also brought the pH of the dye solutions to neutral from acidic. Seed germination bioassay study exhibited that when inoculated dye solutions were used, seed showed germination while uninoculated dyes inhibited germination even after four days of observation. Similarly, microbial growth was also inhibited by uninoculated dyes. The excellent performance of A. niger and P. chrysporium in the biodegradation of textile dyes of different chemical structures suggests and reinforces the potential of these fungi for environmental decontamination.

Abstract:The aim of this study was to isolate, characterize, and evaluate the potential of petroleum hydrocarbon (PHC)-degrading bacterial strains from oil-contaminated soil in the Meerut region. Among 59 oil-degrading bacterial cultures isolated from the oil-contaminated soil samples, 1 Bacillus species, 2 species of Pseudomonas, and 1 species of Micrococcus, identified on the basis of biochemical and 16s rDNA sequencing, were found to have the ability to utilize PHCs such as benzene, diesel, toluene, anthracene, and naphthalene. These strains were selected for further study to measure the quantitative determination of PHC metabolization. Along with these selected strains, a mixed bacterial consortium was formulated and used for PHC degradation. Among the individual strains, Pseudomonas sp. APHP9 performed better than the other bacterial isolates. Maximum biodegradation of benzene and toluene was done by the bacterial consortium. The mean growth rate constant (K) of soil isolates also increased with a successive increase in PHC concentration. Moreover, Bacillus sp. APHP6, Pseudomonas sp. APHP9, Pseudomonas sp. APBP1, Micrococcus sp. APIO4, and the consortium resulted in a 54.8%, 60.2%, 40.9%, 32.5%, and 66.2% decrease in benzene concentration and a 61.2%, 68.4%, 53.7%, 39.3%, and 75.4% decrease in diesel concentration, respectively, after 6 days of incubation as estimated by HPLC analysis.