High level of laccases production by Trametes trogii culture on olive mill wastewater‐based media, application in textile dye decolorization

BACKGROUND: Laccases are receiving increasing attention as potential industrial enzymes in various applications. Therefore, it is important to find inexpensive and optimized media for large-scale commercial production. The present work aims to valorizeolive millwastewater(OMW)by itsuseasbasemediaforlaccasesproduction byTrametestrogii anduseofthelaccases produced for decolorizing textile dyes. RESULTS: A high yield of 25120 U L −1 of laccases was obtained at an OMW:water ratio of 80:20 enriched with 2 g L −1 of urea corresponding to initial biochemical oxygen demand (BOD5), chemical oxygen demand (COD) and total phenol concentrations of 18.4, 46 and 4.6 g L −1 respectively. The partially purified laccases resulted in 85% decolorization of blue tubantin GLL 300 and black tubantin VSF 600, and 45% decolorization of blue solophenyl after 6 h of incubation. Subsequent additions of the same dye dose to the reaction mixture resulted in a very significant decrease in laccases activity after the third dye addition. CONCLUSION: The use of OMW for laccases production is a cost effective process. The laccases produced can be applied to the decolorization of textile wastewaters. c � 2009 Society of Chemical Industry