Production of Enzymes for Industrial Wastewater Treatment: Proof of Concept and Application to the Textile Dye Industry

Report to the Water Research Commission on the project " The production of a cocktail of hydrolytic enzymes from an anaerobic sulphidogenic bioreactor fed with sulphate reducing bacteria and municipal sludge for the treatment of biological and industrial wastewater: proof of concept. " ii DISCLAIMER This report has been reviewed by the Water Research Commission (WRC) and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the WRC, nor does mention of trade names or commercial products constitute endorsement or recommendation for use. iii EXECUTIVE SUMMARY Background A previous Water Research Commission Project (WRC Report No: 1170/1/04) into the enzymology of solubilisation of municipal sewage sludge (Rhodes University BioSURE Process®) identified the involvement of a plethora of hydrolase enzymes such as phosphatases, sulphatases, proteases, lipases, endoglucanases and glucosidases (Pletschke et al. isolated from a biosulphidogenic reactor. Furthermore it was found that these enzymes could be used, in situ, to bioremediate effluents from acid mine drainage, tanneries and abattoirs. It is the intention of the current research to exploit this idea further and undertake a thorough investigation to show that hydrogenase enzymes, also found within the biosulphidogenic reactor, could be used to bioremediate industrial waste effluent from the textile dye industry. Azo dyes are the most commonly used colouring compounds (Pearce et al., 2003) and they were therefore used in this study to investigate the ability of sulphate reducing bacteria (SRB) and associated cytoplasmic hydrogenase enzymes to degrade them under anaerobic conditions. Several advantages of using such a system are forthcoming: 1) Although the enzymes from the sulphidogenic bioreactors are produced under anaerobic conditions, they are perfectly able to work within an aerobic environment. 2) Using enzymes in a sulphidogenic environment supports that the sulphide produced would be strongly inhibitory to the survival and proliferation of pathogens. 3) Biological (enzymatic) processes have an added advantage over traditional chemical/physical methods as they are regarded as "clean and green". 4) The high cost of industrial enzymes is prohibitively expensive and so the use of these enzymes, from the BioSURE Process®, is a cheap alternative and a tool for bioremediation. The novelty of our approach allows for the generation of the essential enzymes within a sulphidogenic bioreactor with a simultaneous in situ 'one-pot' bioremediation of industrial effluent from the textile industry. Hypothesis Enzymes generated within a sulphidogenic bioreactor were capable of totally decolouring and degrading textile …