Inhibition Effects of Antibiotics Ampicillin and Gentamycin on the Methanogenic Activity of Anaerobic Biomass Publisher



Heidari M¹ ; Nabavi BF¹ ; Khouzani HS¹ ; Amin MM² Show Affiliations
Source: International Journal of Environmental Health Engineering Published:2012

Abstract

Aims: Inhibition behavior of two types of antibiotics including Ampicillin and Gentamicin on specific methanogenic activity of anaerobic biomass has been investigated. Materials and Methods: A total of 18 Specific Methanogenic Activity (SMA) tests were conducted in 120-ml vials containing 40 v/v% substrate, 37 v/v% biomass and 23 v/v% biogas in batch mode for 20-25 days. Produced methane was measured by gas replacement with 2N KOH solution as CO2 absorbent. Three volatile fatty acids (VFAs) including acetic acid, propionic acid, and butyric acid were used as co-substrate. Results: In the tests with 200, 500 and 1000 mg/l of ampicillin at presence of acetic acid, the cumulative SMA were 66, 101, and 154 ml CH4/g VSS.d, those of with propionic acid were 25, 35, and 46 ml CH4/g VSS.d, and with butyric acid the values of 198,140, and 245 ml CH4/g VSS.d were obtained respectively. In the experiments with 100, 500 and 1000 mg/l of gentamicin the cumulative SMA were 141, 204, and 257 ml CH4/g VSS.d for acetic acid as a substrate, 54, 72 and 71 ml CH4/g VSS.d for propionic acid, and 139, 74, and 85.5 ml CH4/g VSS.d for butyric acid, respectively. Conclusion: At the same concentrations, ampicillin showed more inhibitory effect than gentamicin on anaerobic decomposition of biomass. Within the used VFAs, the inhibitory effects of propionic acid was greater than acetic acid and butyric acid. © 2012 Medknow. All Rights Reserved.