Biodegradation of Phenol and Phenolic Derivatives by a Mixture of Immobilized Cells of Aspergillus Awamori and Trichosporon Cutaneum

摘要

Two immobilized systems of Aspergillus awamori NRRL3112 and Trichosporon cutaneum R57 on modified polyamide beads were obtained. The optimal conditions for immobilization of strains Aspergillus awamori NRRL3112 and Trichosporon cutaneum R57 on polyamide beads were determined. It was found that by combined action of two immobilized systems it is possible to degrade up to 1.5 g???·L ?￠????1 phenol, while individually immobilized and free cells did not have this capacity (degrade up to 1 g???·L 1 ). The high potential possibility and the synergistic action of both immobilized systems were proved. Biodegradation of different phenolic derivatives was investigated - 2-chlorophenol (2-CP), 3-chlorophenol (3-CP), 4-chlorophenol (4-CP), 2,4-dichlorophenol (2,4-DCP), 4-n-nonylphenol (4-NP), 3-methoxyphenol (3-MP), bisphenol A (BPA), 4-chloro-3,5-dimethylphenol (chloroxylenol?￠????ChX), and 2-benzyl-4-chlorophenol (chlorophen?￠????ChP). It was found that the utilization of phenol, BPA, and 2,4-DCP was very fast (16 h); 2-CP, 3-CP, 4-CP, and 3-MP were utilized for 40 h in the range from 44 % to 72 %; NP and ChP were degraded very slowly (about 30 % for 40 h), while ChX remained unchanged for 40 h. The studied phenolic derivatives were listed in the following order, depending on the degree of biodegradation by the two immobilized strains Aspergillus awamori NRRL3112 and Trichosporon cutaneum R57: Phenol > BPA > 2,4-DCP > 3-MP > 3-CP > 2-CP > 4-CP > ChP > NP > ChX. The rate of biodegradation of phenol and some phenolic derivatives with a concentration of 0.1 g???·L ?￠????1 and 0.3 g???·L ?￠????1 were determined. The advantages of the two combined immobilized systems for biodegradation of phenol and phenolic derivatives as compared to the separate immobilized systems of the two stains and free cells were proved.