Optimizing degradation of olive oil mill waste water using Paecilomyces variotii

الملخص EN

Twenty six microbial isolates (ten fungal, nine yeast and seven bacterial isolates) were isolated from the Olive Oil Mill Waste Water (OOMW) which was extracted from effluent of olive oil industry factory.

All isolates were tested for its growth on media containing 10% OOMW as sole carbon source.

It was found that (three fungal, two yeast and two bacterial isolates) had the ability to grow on this concentration.

These isolates were identified as Paecilomyces variotii, Ascopus stercoraris, Aspergillus terrus, Yarowia lipolytica, Candida tropicalis, Lactobacillus curvatus and Bacillus brevis.

The identified isolates were tested for the biodegradation of phenolic compounds at high concentration of OOMW (25 %).

Paecilomyces variotii was the best isolate as it degraded 10.40 % of the phenolic compounds.

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 for 12 days at 37 ± 1˚C, pH 6, supplement the degradation media with 150 mg/l sucrose, 2.5 g/l yeast extract and 0.070 mmol/l CuSO4 concentration in aerobic conditions with aeration rate 4:1 (v air: v media), shaking at 150 rpm and 6 g/l inoculums size.

In addition, 0.25 kGy was the best dose as it 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.