Microbial bioremediation of Azo dyes: An environmentally sustainable technology

Abstract

Azo dyes, which are the most commonly used dyes in the textile industry, are aromatic compounds with N═N-groups. The treatment of these pollutants has been receiving considerable attention due to their persistence and release of dyes into the environment. The existing treatment approaches are not only expensive but also result in the production of concentrated sludge, which creates a secondary disposal issue. Under particular ecological conditions, a variety of microbes, including bacteria, fungi, algae, and yeasts, can not only decolorize numerous dyes but can also degrade them. In this respect, microbial degradation is a successful, cost-effective, biologically friendly, and ecologically sustainable treatment strategy. This review paper discusses research articles identified in the ScienceDirect bibliographic database for the last 10 years (from January 1, 2010 to June 29, 2022). Only the most appropriate research articles were included in the review process which was identified by searches with keyword phrases Azo-dye degradation with bacteria, fungi, algae, yeast, and microbial consortia. The review paper also emphasizes the constraints that persist and the future scope for the degradation of dyes via genetic engineering. | INTRODUCTIONColor is an important element of human life. Humans, on the whole, prefer to wear colored clothing, consume colored food, and even take colored medicines. The high demand for color in the paper, textile, cosmetics, and food industries has led to an increase in the usage of dyes since the industrial revolution. There currently are approximately 10,000 commercially accessible dyes, and over 700,000 tonnes of dyes are manufactured each year (Tkaczyk et al., 2020).Dye-bearing effluents from industries such as textile, paper and pulp, chemical, petrochemical, and dyeing, include hazardous and persistent organic and inorganic pollutants that can impact the natural environment (Wang et al., 2021). Organic dyes and their intermediates are widely used in the paint, ink, plastics, and textile cosmetics sectors. Azo dyes, contain chromophore -N═N-Azo groups which are responsible for the stability of dyes in water (Singh & Dwivedi, 2020). Azo dyes are the most popular and diverse types of man-made colorants with applications in printing, food, cosmetic, and textile manufacturing. Azo dyes can be carcinogenic, toxic, and adversely affect human health and the environment, including aquatic ecosystems (Singh & Dwivedi, 2020). Due to their complex aromatic structure and xenobiotic characteristics, most dye molecules are difficult to degrade. As a result, different effective treatment methods and strategies for removing these harmful color pollutants from water bodies are necessary (

Bacillus Species with Dye-remediation Potential – A Mini Review

“…Bacterial remediation of synthetic dyes involves a high degree of removal and mineralization of harmful compounds which is economically viable, results in minimal production of sludge and is faster than that performed by fungi (Saratale et al, 2011;Mishra et al, 2020;Fletcher et al, 2021;Huda et al, 2022;Panwar et al, 2023). Bacteria mineralize dye by enzymatic action and/or biosorption (Mustapha and Halimoon, 2015;Lellis et al, 2019;Tripathi et al, 2023).…”

“…For these reasons, the development of eco-friendly and sustainable dye-remediation strategies were initiated to mitigate the environmental impact of these dyes (Manzoor and Sharma, 2020;Akter et al, 2023). The most common dye-remediation strategy is the microbial remediation which involves the use of microorganisms from different species of bacteria, fungi and algae, which proves to be very effective (Sani et al, 2021;Panwar et al, 2023). Microorganisms are ideally suited to the task of remediating dyes due to their size, adsorption capacity and possession of enzymes that allow them to utilize the dyes as food.…”