Decolourization Studies of a Novel Textile Dye Degrading Bacterium

Abstract

Textile dyes represent one of the most complicated pollutants because of their complex nature and difficulty in degradation. More than 100,000 commercially available dyes are known and the world annual production of the dyestuffs amounts to more than 7 × 10⁵ tonnes (Robinson et al. 2001). It has been estimated that more than 10–15 % of the total dyestuff used in dye manufacturing and textile industry is released in to the environment during their synthesis and dyeing process. Almost 2,80,000 tonnes of textile dyes are discharged every year worldwide (Mass and Chaudhari 2005). In India, annual consumption of dyes by the textile industries is around 6,01,225 tonnes. The release of textile dyes into the environment is of great concern due to colourations of natural waters and also due to toxicity, mutagenicity and carcinogenicity. Various physical and chemical treatment methods are available for colour removal but use more energy and chemicals than biological processes. Moreover, they also concentrate the pollution into solid or liquid sidestreams requiring additional treatment or removal. Therefore, biological treatment is often the most economical alternatives when compared with other physical and chemical processes (Solis et al. 2012). However, it is considered that due to the recalcitrant nature of the textile dyes, the textile wastewaters impart toxicity to the microorganisms making aerobic treatment difficult. On the other hand, treatment under anaerobic conditions (by using anaerobic bacteria like Bacteroids sp., Eubacterium sp., Clostridium sp. etc.) produces aromatic amines which are toxic to the environment (Archna Lokesh and Siva Kiran 2012).