Reduction of olive oil mill waste water phenolic compounds and COD using Paecilomyces variotii

Abstract

The present study aimed to shed light upon the role of microorganisms in biological treatment of phenolic compounds as a one of the widespread pollutants in Egypt. The ability of twenty six different indigenous isolates which isolated from the olive oil mill waste water (OOMW), for growth in media containing 10% and 25% OOMW as sole carbon source was tested. Paecilomyces variotii was the most potent isolate among all isolates as it degraded 10.40 % of the phenolic compounds. These isolate was selected to examine its biodegradation activity under different conditions. The maximum degradation of phenolic compounds and chemical oxygen demand (COD) decrease percentage was (68.14 and 59.12, respectively) obtained at 50% dilution of OOMW. The best environmental conditions for phenolic compound biodegradation and COD reduction, in shacked flasks at 150 rpm were, pH 6.0, temperature 37±1˚C and incubation period 12 days, with the supplementation of the degradation media with 150 mg/l sucrose, 2.5 g/l yeast extract and 0.070 mmol/l CuSO4, and 4ml inoculums size. In addition, low dose of gamma radiation (0.25 kGy) enhanced the fungal biodegradation activity, and led to increase the phenolic compounds biodegradation percent 8.7% than the optimum conditions previously mentioned. Finally, the biotreated OOMW was lower toxicity to environment than untreated one.