Removal of aqueous phenol using immobilized enzymes in a bench scale and pilot scale three-phase fluidized bed reactor

Abstract

The main objective of this work was to investigate the removal of aqueous phenol using immobilized enzymes in both bench scale and pilot scale three-phase fluidized bed reactors. The enzyme used in this application was a fungal tyrosinase [E.C. 1.14.18.1] immobilized in a system of chitosan and alginate. The immobilization matrix consisted of a chitosan matrix cross-linked with glutaraldehyde with an aliginate-filled pore space. This support matrix showed superior mechanical properties along with retaining the unique adsorptive characteristics of the chitosan. Adsorption of the o-quinone product by the chitosan reduced tyrosinase inactivation that is normally observed for this enzyme under these conditions. This approach allowed reuse of the enzyme in repeated batch applications. For the bench scale reactor (1.2-l capacity) more than 92% of the phenol could be removed from the feed water using an immobilized enzyme volume of 18.5% and a residence time of the liquid phase of 150 min. Removal rates decreased with subsequent batch runs. For the pilot scale fluidized bed (60 l), 60% phenol removal was observed with an immobilized enzyme volume of 5% and a residence time of the liquid phase of 7 h. Removal decreased to 45% with a repeat batch run with the same immobilized enzyme.

Tyrosinase‐catalysed grafting of food‐grade gallates to chitosan: surface properties of novel functional coatings

“…19,20 Tyrosinase-containing chitosan has been exploited in selective phenol removal. [21][22][23][24][25] It may also have potential to be used in detection of phenol vapours, such as volatile p-cresol. 26 Tyrosinase from Trichoderma reesei fungus has been recently reported to react with complex compounds such as proteins and proteinaceous fi bres more effi ciently than the well-known and commercially available tyrosinase from a common mushroom Agaricus bisporus.…”

Experimental behaviour and design model of a fluidized bed reactor with immobilized peroxidase for phenol removal

“…(29) when z = L. Because the sample time interval used in the experiments fulfils the condition expressed in Eq. (28), it can be affirmed that…”

“…As regards published papers related to fluidized bed with immobilized peroxidases, Trivedi et al [28], using soybean peroxidase entrapped on a hybrid silica/alginate gel, investigated phenol elimination in continuous in a fluidized bed reactor with recirculation. Also, Ensuncho et al [29], used immobilized tyrosinase to catalyze the phenol conversion to o-quinones, in the presence of oxygen, in a three-phase fluidized bed reactor. In this study, the enzyme was physically retained in a mixed matrix of chitosan and alginate.…”

Performance of pulsed plate bioreactor for biodegradation of phenol

“…Immobilization binds the microorganism to a solid support and the sludge separation unit is not required. The immobilised cell reactors with various reactor configurations namely packed bed or trickle bed reactors [4,[40][41][42][43][44][45][46], fluidised bed reactors [3,39,[47][48][49][50][51][52][53][54][55] have been reported for the biodegradation of phenol. The use of packed bed reactors or trickle bed reactors with immobilized cells in biotechnological processes presents a series of problems.…”