ABSTRACT
The Bacillus sp. strain PHN 1 capable of degrading p-cresol was immobilized in various matrices namely, polyurethane foam (PUF), polyacrylamide, alginate and agar. The degradation rates of 20 and 40 mM p-cresol by the freely suspended cells and immobilized cells in batches and semi-continuous with shaken cultures were compared. The PUF-immobilized cells achieved higher degradation of 20 and 40 mM p-cresol than freely suspended cells and the cells immobilized in polyacrylamide, alginate and agar. The PUF- immobilized cells could be reused for more than 35 cycles, without losing any degradation capacity and showed more tolerance to pH and temperature changes than free cells. These results revealed that the immobilized cell systems are more efficient than freely suspended cells for degradation of p-cresol.
Subject(s)
Bacillus/metabolism , Cells, Immobilized/metabolism , Cresols/metabolism , Water Pollutants, Chemical/metabolism , Biodegradation, EnvironmentalABSTRACT
A bacterium capable of utilizing p-cresol as sole source of carbon and energy was isolated from soil and identified as a Bacillus species. The organism also utilized phenol, o-cresol, m-cresol, 4-hydroxybenzoic acid, and gentisic acid as growth substrates. The organism degraded p-cresol to 4-hydroxybenzoic acid, which was further metabolized by a gentisate pathway, as evidenced by isolation and identification of metabolites and enzyme activities in the cell-free extract. Such a bacterial strain can be used for bioremediation of environments contaminated with phenolic compounds.
