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Phenol and 4-chlorophenol biodegradation by yeast Candida tropicalis in a fluidized bed reactor

Paper ID Volume ID Publish Year Pages File Format Full-Text
4561 232 2008 11 PDF Available
Title
Phenol and 4-chlorophenol biodegradation by yeast Candida tropicalis in a fluidized bed reactor
Abstract

The objective of this work was to evaluate (i) the hydrodynamics and oxygen transfer characteristics of a fluidized bed reactor (FBR) and (ii) their performance in the continuous biodegradation of a phenol (Phe) and 4-chlorophenol (4-CP)-containing influent when the FBR was loaded with Candida tropicalis yeast immobilized onto granular activated carbon (GAC) particles. The first part was carried out in terms of the behavior of mixing time (tm95), bubble diameter (dB), gas hold-up (ɛG), gas–liquid interfacial area (a′) and oxygen transfer coefficient (kLa) in biphasic (gas–liquid) and triphasic (gas–liquid–carbon) systems, both batch-wise operated in pseudohomogeneous regime at superficial gas flow rates UG below 1.72 cm s−1. Mixing time was determined using a tracer technique, ɛG was measured by the volume expansion method; (dB) was determined by the procedure reported by Poulsen and Iversen and kLa was determined by a transient gassing-in technique. It was found that hydrodynamic variables were severely influenced by GAC particles. The dB values were smaller in triphasic than in biphasic system, with the consequent increase in the ɛG, a′ and kLa values.The removal efficiencies of both Phe and 4-CP in the bioreactor challenged at increasing volumetric loading rate of pollutants were determined in the second part of the study. Phe and 4-CP was determined by HPLC. Immobilized biomass on GAC was estimated from their total nitrogen content. Regarding continuous biodegradation experiments, the FBR was capable of efficiently removing Phe at volumetric loading rates as high as 60 mg Phe L−1 h−1 when it was fed as the sole carbon source. Beyond this point, removal efficiencies drastically decreased. When operated with a feed consisting of a mixture of Phe and 4-CP, the FBR was able to remove more than 98% of 4-CP in the range of volumetric loading rates of 4.1 mg 4-CP L−1 h−1 and 55 mg Phe L−1 h−1 with no apparent deterioration of bioreactor performance.

Keywords
Bubble column; Candida tropicalis; Chlorophenol biodegradation; Fluidized bed reactor; Immobilized yeast; Phenol biodegradation
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Publisher
Database: Elsevier - ScienceDirect
Journal: Biochemical Engineering Journal - Volume 38, Issue 2, 15 February 2008, Pages 147–157
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us