Bioremediation Efficiency of Heavy Metals and Azo Dyes by Individual or Consortium Bacterial Species Either as Free orImmobilized Cells: A Comparative Study

Abstract

THE OBJECTIVE of the present study was to compare between free and immbolized bacterial cultuer/s in bioremediation of heavy metals and dyes to reduce environmental pollutants with the help of biological entities. The bacterial consortium consisting of Sphingomonas paucimobilis, Rhizobium radiobacter, and Bacillus subtilis was developed due to capabilities of the three bacterial species to remove heavy metals from industrial waste water and decolorize methyl orange and Congo red textile azo dyes than their corresponding single cultures. The immobilization of bacterial consortium on Ca-alginate increased its heavy metals removal efficiency more than 10% compared to consortium of free cells after 4 days. Also, decolorization ability of immobilized consortium was conducted for shorter time and higher concentrations of dyes than that of free one. The greater efficiency of immobilized consortium than free single culture may be correlated to synergistic activity of different metabolites of bacterial cultures and protection of cells from toxic pollutants that provided by Ca-alginate matrices which promoting an efficient bio-treatment of industrial effluents containing dyes and heavy metals.

Bioremediation of Textile dyes by Fungal-Bacterial Biofilms

“…It has been reported that mixed bacterial cultures from different habitats showed high decolorization of dye molecules in 15 days (Knapp & Newby, 1995). Similar results have been reported by another study that immobilized bacterial consortium of the three bacterial species (Sphingomonas paucimobilis, Rhizobium radiobacter, and Bacillus subtilis) had the ability to decolorize azo dyes more efficient than free bacterial cells of single culture (Allam, 2017). Mahmood et al (2015) found that, the consortium of 6 bacterial isolates was able to decolorize 84% of 200 ppm of red, green, black, yellow, and mixed dyes within 24 hours while individual strain required 72 hours.…”

“…It has been reported that different microbial species present in consortia of biofilms each with different metabolic degradation pathway are capable of degrading several pollutants including dyes and heavy metals either individually or collectively (Gieg et al, 2014: Mitra andMukhopadhyay, 2015). Decolorization of synthetic dyes using consortia offers advantages over the use of single microbial strains (Sudha et al, 2014) due to higher degrees of biodegradation resulted from synergistic metabolic activities of the microbial community (Allam, 2017). It has been reported that mixed bacterial cultures from different habitats showed high decolorization of dye molecules in 15 days (Knapp & Newby, 1995).…”

Statistical modeling of methylene blue degradation by yeast-bacteria consortium; optimization via agro-industrial waste, immobilization and application in real effluents

“…Remarkably, the entrapment in alginate microspheres exhibited higher efficacy in biodegradation process than freely-suspended state. As highlighted by [ 90 , 91 ], the superior properties provided by immobilization, including better mechanical strength, stability, tolerance against adverse environmental conditions and hazardous by-products, protection of cells, viability preservation over a prolonged period and simplicity/ easiness of reuse/ recovery could explain such results. In addition, natural/ non-synthetic origin of alginate hydrogel contributed in successful degradation process by its low toxicity and biocompatibility traits.…”

The Potential Role of Sphingomonas Paucimobilis in Bioremediation of Soils Contaminated With Hydrocarbon and Heavy Metal

“…There are also indications that the removal capacity of S. paucimobilis was higher for Pb than Cd. Allam (2017) reported that the removal ability of Pb was higher than Cd (57 and 53%).…”