Received: 5 September 2017 | Revised: 14 October 2017 | Accepted: 29 October 2017 DOI: 10.1002/jobm.201700497 RESEARCH PAPER Statistically optimized ceftriaxone sodium biotransformation through Achromobacter xylosoxidans strain Cef6: an unusual insight for bioremediation Ahmed Anan 1 | Khaled M. Ghanem 1 | Amira M. Embaby 2 | Ahmed Hussein 2,3 | Moustafa Y. El-Naggar 1 1 Faculty of Science, Botany and Microbiology Department, Alexandria University, Egypt 2 Institute of Graduate Studies and Research, Department of Biotechnology, Alexandria University, Egypt 3 Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA Correspondence Amira M. Embaby, Institute of Graduate Studies & Research, Alexandria University, 163 EL-Horreya Avenue, Alexandria 21526, Egypt. Email: amira.embaby@alexu.edu.eg The present study underlines a unique promising approach toward efficient biotransformation of ceftriaxone sodium (Ceftx), a highly frequent prescribed cephalosporin antibiotic, by a newly bacterium namely Achromobacter xylosoxidans strain Cef6 isolated from Ceftx contaminated raw materials in pharmaceutical industries. A three step sequential statistical-mathematical approach (Plackett- Burman design [PBD], Central Composite Design [CCD], and ridge-canonical analyses) was anticipated to optimize the biotransformation process. Ceftx concentration and medium volume: bottle volume ratio, two key determinants, significantly (p < 0.05) affected the process outcome deduced by regression analysis of PBD’ data. CCD and ridge-canonical analyses localized the optimal levels of Ceftx concentration and medium volume: 250 ml bottle volume ratio to be 0.39 and 7.973 g Ceftx/L modified tryptic soy broth achieving Ceftx biotransformation (100%) after 39 h under aerobic static conditions at 30 °C, irrespectively deduced via HPLC analysis. Impressively, only one of five Ceftx byproducts was detected by the end of the biotransformation process. To the best of authors’ knowledge, this is the first report addressing a detailed study regarding efficient biotransformation of Ceftx by single bacterium not bacterial consortium under aerobic conditions. Present data would greatly encourage applying this approach for decontamination of some Ceftx contaminated environmental sites. KEYWORDS Achromobacter xylosoxidans strain Cef6, biotransforamation, ceftriaxone sodium, HPLC, statistical- mathematical modeling 1 | INTRODUCTION Overuse and misuse of antibiotics in terms of tons for medical and non-medical purposes would result in continuous elevation of the annual rate of antibiotics consumption worldwide [1–3]. This in turn would continuously maximize the amounts of introduced antibiotics and their metabolites as wastes to the wider environment. There exist certain sources representing prime routes for antibiotics’ entrance to the wider environment, of most abundant are effluents of pharmaceutical manufactur- ing plants [4,5], hospital effluents [6,7], domestic and non- domestic municipal sewage [8–10], aquaculture [11–13], agriculture, and livestock production [14,15]. The total worldwide antibiotic consumption enlarged by more than 30 J Basic Microbiol. 2017;1–11. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim | 1 www.jbm-journal.com