Batch and continuous decolorisation of bleached kraft effluents by a white‐rot fungus

Abstract

The white-rot fungus Coriolus versicolor, used in the form of mycelial pellets, provided an effective means to decolorise lignin-containing kraft El-stage effluent from wood treatment processes. The mycelial pellets adsorbed the chromophores of the liquor and oxidised them in the presence of glucose. For an original liquor containing 7000 colour units (CU), the mean colour removal in batch experiments was estimated to be 300 CU g-' mycelium h-I. The adsorption process and the oxidation process (following glucose addition) generally operated best at between pH 4 and 5, and at temperatures of 25 to 3 0 T , with a ratio of glucose to mycelium of 0.36. for a 2 4 h experiment. Magnesium ions accelerated the oxidation process. Decolorisation was then tested in a continuous reactor. The rate of loss of activity of the pellets was 1% per day and no mechanical damage to the pellets was observed in the reactor. With a liquor of 5600 CU a 50% decolorisation was attained in 15 to 30 h using 4.64 g dm-' mycelium. This represents a rate of chromophore consumption of 30 CU g-' mycelium h-'.

Colour removal from bagasse-based pulp mill effluent using a white rot fungus

“…In further investigations, this optimum value was used. Earlier investigators [7,14,15] for maximum decolourization reported similar values of pH range, 3.9 to 6.0. …”

“…In the present investigation, the initial colour concentration of 1175 CU gave 89.8% ef®-ciency compared to 79.6% in the culture¯ask with initial colour concentration of 4700 CU. It was reported [15] that a maximum decolourization ef®ciency of 90% was obtained at the lowest colour concentration of 1000 CU in the range studied. The maximum decolourization of 65% with 30% dilution of the ef¯uent compared to 21% decolorization ef®ciency without dilution was also reported in the literature [8].…”

Decolorization of phenolic effluents by soluble and immobilized phenol oxidases

“…The initial rate of descolorization was more rapid when using the enzyme but the total colour removed was greater using the fungus. However, oxidative treatment of effluent using fungi required glucose as an additional carbon source and adjustment of the pH to 4.5 (Royer et al 1985). This would add to the cost of a treatment system.…”

“…Treatment of phenolic effluents with immobilized white-rot fungi removes colour and degrades toxic compounds (Eaton et al 1982;Royer et al 1985). The mycelial colour removal (MyCoR) process uses Phanerochaete chrysosporium mycelium immobilized on rotating biological contactors (Sundman et al 1981;Eaton et al 1982), and requires an initial growth period after inoculation prior to exposure to the effluent.…”

“…The mycelial colour removal (MyCoR) process uses Phanerochaete chrysosporium mycelium immobilized on rotating biological contactors (Sundman et al 1981;Eaton et al 1982), and requires an initial growth period after inoculation prior to exposure to the effluent. Coriolus versicolor immobilized in calcium alginate beads (Royer et al 1983) or as mycelial pellets (Royer et al 1985) has been used in air-lift reactors, but there are diffusional limitations and alkaline effluents have to be adjusted to pH 4-5 before treatment.…”