Positive effect of antibiotics on methane production from corn straw

Anaerobic digestion (AD) of corn straw (CS) inoculated with waste sewage sludge (WSS) is a promising approach for energy utilization of both lignocellulosic wastes and WSS. However, few studies about the effect of antibiotics contained in WSS on AD of CS are reported, which hinders the efficient conversion from CS to methane (CH4). Antibiotics including tetracycline (TC) and azithromycin (AZM) were used to evaluate their effects on AD of CS inoculated with WSS in this study. As results, the reactor with AZM addition achieved 167.67 mL/g VS CH4 yield, which was increased 65.22% compared with CTRL (without any antibiotics addition, 101.48 mL/g VS CH4 yield) by playing roles at the hydrolysis, acidogenesis/acetogenesis and methanogenesis stages during 20 days of AD. Similarly, addition of TC performed 25.38% (127.27 mL/g VS) higher CH4 yield than CTRL mainly by promoting the acidogenesis/acetogenesis and methanogenesis stages. Specifically, phyla Bacteroidetes, Actinobacteria and genera Methanosarcina, Methanobrevibacter were considered as functional microorganisms for AD of CS with AZM addition. Results from this study provide a new insight for enhancing CH4 yield from CS.