Decolourisation and dephenolisation potential of selected Aspergillus section Nigri strains – Aspergillus tubingensis in olive mill wastewater

Abstract

Aspergillus section Nigri strains Aspergillus aculeatus Ege-K 258, A. foeditus var. pallidus Ege-K156, A. niger Ege-K 4 and A. tubingensis Ege-K 265 were used to treat olive mill wastewater (OMW) in an investigation aimed at exploring their dephenolisation and decolourisation ability and, consequently, the economic feasibility of using any or all of these strains in a pre-treatment step in the processing of OMW. Of these strains A. tubingensis Ege-K 265 resulted in an 80% decolourisation of twofold-diluted OMW and a 30% decolourisation of undiluted OMW; in addition, it was able to remove approximately 30% of all phenolic compounds in both twofold-diluted and undiluted OMW. We conclude that A. tubingensis Ege-K 265 could be effectively used in the pre-treatment step of a combined aerobic-anaerobic process to solve the environmental problems caused by OMW in Mediterranean countries.

Biodegradation of Toxic Compounds in Olive Mill Wastewater by a Newly Isolated Potent Strain: <i>Aspergillus niger</i> van Tieghem

“…A slight darkening of the mycelia pellets was also observed. The discoloration was probably due to the degradation and adsorption of some phenolic compounds on the fungal mycelium, these results were already shown by Ongen et al [13]. This adsorption may be due to the hydrogen bound between phenolic compounds and proteins or to the chitin of the mycelial wall, which has a strongly coagulant effect [11].…”

“…Hamdi et al [18] reported that after 72 h, the COD removal rate determined on OMW filtrate fermented by A. niger was 61.6% in flasks and 52.5% in the fermentor. Ongen et al [13] reported that A. tubingensis Ege-K 265 was able to remove 26.35% of the phenolic compounds in two-fold-diluted OMW medium within 48 h, while 29.13% of phenolic compounds were removed from the undiluted medium within 48 h. At the same time, total phenolic removals were correlated with tannase production (Figure 2). The maximum tannase production reached to 0.867 EU/ml on the 3 rd day of incubation.…”

“…In the sample, COD, polyphenols, dark color intensity and pH were measured. Chemical oxygen demand (COD) were determined according to APHA standards methods [12].The dark color intensity was determined by measuring the sample's absorbance at 395 nm respectively using a CARY 1E VA RIAN spectrophotometer, in 1cm path-length cells [13]. Determination of the concentration of total polyphenols was carried out with the official spectrophotometric procedure (720 nm) in which the reagent Folin-Ciocalteu was used as a selective reagent for polyphenols [14] using a CARY 1E VARIAN spectrophotometer, the results were expressed as gram of gallic acid per liter.…”

Augmentation of biodegradability of olive mill wastewater by electrochemical pre-treatment: Effect on phytotoxicity and operating cost

“…Liquid cultures were conducted in duplicate, in Erlenmeyer flasks containing 50 cm 3 of OMW supplemented uniformly with 0.35% (NH 4 ) 2 SO 4 and 0.065% KH 2 PO 4 (w/v). The flasks were inoculated with 500 mg dry weight fungal biomass per litre OMW and incubated in a rotary shaker at 150 rpm and 28 • C. The growth was followed as dry weights of mycelium following the filtering of the samples through glass microfibres (GF/A Whatman Inc.) and drying 105 • C [18].…”

Dephenolization and decolorization of olive mill wastewater through sequential batch and co-culture applications

“…Among the ligninolytic systems those containing MnP and Lac are the most common (Dias et al 2004). Different compounds are described as inducers or mediators of these enzymes to minimize the effects caused by the high concentrations of phenolics and OMW must be diluted prior to either aerobic or aneraobic process (D'Annibale et al 1998;Robles et al 2000;Ö ngen et al 2007). Although dilution decreases the concentration of the toxic compounds present in wastewater, it also causes an increase in waste volume, which is not desired.…”