ABSTRACT
Cephalexin is a semisynthetic cephalosporin antibiotic intended for oral administration. The nucleus of cephalexin is related to that of other cephalosporin antibiotics. The effluent and sludge from these industries contain high concentration of cephalexin and its intermediates which results in depletion of oxygen and destruction of aquatic animals due to their toxic nature. Anaerobic transformation of cephralexin occurred through Pseudomonas aeruginosa, Escherichia coli and Achromobacter species available in the mixed culture of an anaerobic digester. Cephralexin was transformed to 7-arnino-3-deacetoxycephalosporanic acid (7-ADCA) and acyl group by the microorganisms in the presence of volatile fatty acid as co-substrate. This study was conducted to examine the feasibility of using an anaerobic fluidized bed reactor for the transformation of cephalexin. Rapid start-up of the reactor was achieved by using anaerobic cephalosporin enrichment cultures as the inoculum. During the continuous operating periods, low concentrations (3.5 mg/L) of cephalexin were transformed to 7-ADCA and acyl group at hydraulic retention times of 15-48 hours with 150 mg COD/L of volatile fatty acid. Cephalexin concentrations as high as 80 mg/L was transformed to 7-ADCA with a relatively low supply of (200 mg/L) of volatile fatty acid. Results of this study suggest that the anaerobic fluidized bed system is a feasible process for the anaerobic treatment and remediation of cephalexin based pharmaceutical waste sludge and effluent.
Key words- Anaerobic transformation, cephalexin, fluidized bed reactor, pharmaceutical effluent, bioaugmentation, enricher reactor
Corresponding author: R. SARAVANANE, Environmental Engineering Laboratory, Department of Chemical Engineering, Indian Institute of Technology, Madras, Chennai -600 036, India
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