Luffa cylindrica Immobilized with Aspergillus terreus QMS-1: an Efficient and Cost-Effective Strategy for the Removal of Congo Red using Stirred Tank Reactor

Abstract

Microbial populations within the rhizosphere have been considered as prosperous repositories with respect to bioremediation aptitude. Among various environmental contaminants, effluent from textile industries holds a huge amount of noxious colored materials having high chemical oxygen demand concentrations causing ecological disturbances. The study was aimed to explore the promising mycobiome of rhizospheric soil for the degradation of azo dyes to develop an efficient system for the exclusion of toxic recalcitrants. An effluent sample from the textile industry and soil samples from the rhizospheric region of Musa acuminata and Azadirachta indica were screened for indigenous fungi to decolorize Congo red, a carcinogenic diazo dye, particularly known for its health hazards to the community. To develop a bio-treatment process, Aspergillus terreus QMS-1 was immobilized on pieces of Luffa cylindrica and exploited in stirred tank bioreactor under aerobic and optimized environment. Quantitative estimation of Congo red decolorization was carried out using UV-Visible spectrophotometer. The effects of fungal immobilization and biosorption on the native structure of Luffa cylindrica were evaluated using a scanning electron microscope. A. terreus QMS-1 can remove (92%) of the dye at 100 ppm within 24 h in the presence of 1% glucose and 1% ammonium sulphate at pH 5.0. The operation of the bioreactor in a continuous flow for 12 h with 100 ppm of Congo red dye in simulated textile effluent resulted in 97% decolorization. The stirred tank bioreactor was found to be a dynamic, well maintained, no sludge producing approach for the treatment of textile effluents by A. terreus QMS-1 of the significant potential for decolorization of Congo red.

Use of Ionic Liquid Pretreated and Fermented Sugarcane Bagasse as an Adsorbent for Congo Red Removal

“…Currently, ozonation, coagulation/flocculation, oxidation, and ultrafiltration are used for the dye removal [4]. All these methods have intense energy requirements, hence, are costly and release hazardous by-products [5]. Therefore, the development of an eco-friendly, efficient, and low-cost technique is needed for dye removal.…”

Enrichment, Isolation, and Screening of Dye-Decolorizing Halotolerant Microbial Strains

“…Thousands of varied synthetic coloring agents are used by dyeconsuming industries for diverse operations (Laraib et al, 2020). According to statistics, 30-50% of these dyes are untreated and discharged into natural water systems (Giovanella et al, 2020), leading to serious water contamination in the surroundings of the printing and dyeing industries.…”

Recent Achievements in Dyes Removal Focused on Advanced Oxidation Processes Integrated with Biological Methods

“…Bacterial treatment Isolation of new strains or consortia from activated sludge, oxidation ditch, palm oil mill effluent or desert soil, alkali-, haloand thermophilic strains implementation, consortium with algae, bacteria immobilization, co-substrate addition, proposal of mechanisms, pathways genome and transcriptome analysis [109][110][111][112][113][114][115][116][117][118][119] Fungal treatment Implementation of microbial consortium (e.g., yeast consortium with ability of lignin valorization dye treatment and biodiesel production), fungi immobilization, isolation of new strains from plant roots or effluent site [120][121][122][123][124][125][126][127][128][129][130] Enzyme treatment Optimization of enzyme production, enzyme immobilization, metabolites and toxicity assessment [131][132][133][134][135][136] Algal treatment…”

“…Among the microorganisms that are able to produce enzymes necessary for dye degradation under aerobic conditions, white-rot fungi are the most efficient [ 215 , 231 ]. However, experiments were conducted on bacteria (especially Streptomyces ) [ 34 , 119 , 134 ], yeast [ 127 ], and other fungi [ 120 , 124 , 128 , 202 , 203 ] for the implementation of aerobic dye removal. Although bacterial laccase is less efficient in the azo bond cleavage than fungal laccase, this drawback may be partially overcome by the addition of a natural redox mediator—methyl syringate in 0.5 mM concentration led to the Acid Orange 63 decolorization increase from 0 to 35% [ 34 ].…”

“…Aerobic treatment was investigated with the usage of whole microbial cells [ 120 ] as well as isolated enzymes [ 34 ]. In the case of whole microbial cells, the experiments were conducted on plates [ 128 ], in Erlenmeyer flasks [ 119 , 127 , 130 , 202 ], in Erlenmeyer flasks with fungus immobilized in LECA [ 203 ], in stirred tank reactor with Aspergillus niger immobilized on pieces of Luffa cylindrica [ 124 ], in a filled column bioreactor [ 120 ], and in a packed bed reactor [ 119 ], with decolorization efficiency varying between 60 and 97%. As can be seen above, a lot of experiments were conducted with fungi immobilization—this is the result of the morphologic specificity of fungal growth.…”