Study of Microbial Decolorization of Indigo Carmine Dye by Bacillus albus

The synthetic dyes pollution has turned out to be one of the most important environmental problems. Approximately 10000 different dyes and pigments are used industrially and over 0.7 million tons of synthetic dyes are produced annually, worldwide. Synthetic dyes are extensively in the textile dyeing, leather tanning, paper, food and medicine industries. The majority of these dyes are either toxic to flora and fauna or mutagenic and carcinogenic. The disposal of these wastes into receiving waters cause damage to the environment. Therefore, removing them from environment is imperative various methods for physical and chemical decolorization of dyes in wastewater but these methods are rather costly and sometimes product hazardous by-products. In recent years, biodegradation approach of its cost-effectiveness and safe method. In this method, microorganisms, particularly bacteria are used for removing dyes. The goal of microbial treatment is to decolorize and detoxify the dye-contaminated effluents.

In this study, bacillus albus bacteria were isolated Mazandaran industrial wastewater used as an example of gram-positive bacteria. Decolorization by these bacteria was investigated by a system which contained both medium and dye. The effects of operational parameters of indigo carmine including time, initial dye concentration, temperature, pH, shaking/non shaking, aerobic/anaerobic were tested. Ethics code: IR.UMZ.REC.1397.106

The results demonstrated that over a period of 54 h, at 50° C, 100 mg/l of concentration and pH=10, maximum decolorization of 95 percent was performed.

The present study confirms high effectiveness of bacillus strains in dye removal. The main experiment was focused on decolorization of indigo carmine in aeration conditions.