Significant amounts of cephalosporin mycelial dreg (CMD) are still being generated from biopharmaceutical processes, representing both an economic and environmental burden for pharmaceutical factories. This study investigates the microwave (MW) treatment of CMD at a relatively mild temperature (100 degrees C) within 15 min. The results reveal that the MW treatment disintegrates the CMD efficiently and that the residual cephalosporin C (CPC) is almost degraded after sufficient irradiation. MW heating temperature strongly influences the polymer's release. SCOD (soluble chemical oxygen demand), soluble proteins and carbohydrates have significant positive correlations to the temperature (r = 0.993, 0.983 and 0.992, respectively; p <0.01). 3D-EEM fluorescence spectra indicate that the key organic matters relate to temperature as well as microwave energies. Furthermore, more than 99.9% of the residual antibiotics in CMD are degraded by MW irradiation without antibacterial activities that are proven by the possible degradation pathway we elucidate. These results suggest that microwave irradiation treatment not only disintegrates CMD and destroys mycelial cells but also degrades the residual cephalosporin antibiotics, which implies the possibility for practical applications. (C) 2017 Elsevier B.V. All rights reserved.