Biotransformation of Food Dyes by Human Intestinal Bacteria (Streptococcus faecalis, Eschericia coli)

Na Oranusi,Ho Njoku

doi:10.4314/jasem.v10i2.43698

Abstract

Biotransformation of food dyes (Tartrazine and Quinoline yellow) by Streptococcus faecalis and Escherichia coli isolated from human intestinal microflora was investigated. Decolourisation of the media containing the dyes was used as an index of biotransformation. Biotransformation was higher under aerobic than under anaerobic conditions. The results obtained were attributed to the organisms cytosolic flavin-dependent reductases and redox equivalents generated by metabolism of soluble starch which transfer electrons to the chromophoric group of the dyes. The potential health risk of the resulting colourless metabolites (aromatic amines) is under investigation. @JASEM

Highlights

Azo dyes consist of a diazotised amine coupled to an amine or a phenol and contain one or more azo bonds (Chen et al; 1999)
The potential of human intestinal microflora (Escherica coli and Streptococcus facalis) to transform selected food dyes since it may be important in generating carcinogenic, mutagenic and toxic compounds (ii) Decolourisation of the dyes in simulated dye wastewater effluent to assess the potential of these organisms either under monoculture or consortium cultivation in the development of a bioprocess for treatment of dye wastewaters
Identification: Isolate B was identified using various tests: Gram stain, motility, spore stain, and various biochemical tests according to the methods of Cruickshank et al (1980) and Holts and Bergey (1994) Isolate B was tentatively identified as Streptococcus faecalis (S. faecalis) based on the results of the various tests and with reference to Bergey’s Manual of Determinative Bacteriology

Summary

Introduction

Azo dyes consist of a diazotised amine coupled to an amine or a phenol and contain one or more azo bonds (Chen et al; 1999). Standard Inoculum: Colonies were picked from the stock culture of each isolate and E. coli and inoculated into 20 ml nutrient broth contained in 250 ml Erlenmeyer flask. Decolourisation of media which contained the dyes by batch cultures of E. coli and the isolates.

Results

Conclusion