Influence of operational conditions on the performance of biogas bioconversion into ectoines in pilot bubble column bioreactors
María del Rosario Rodero, Raquel Herrero‐Lobo, Víctor Pérez, Raúl Muñoz
Abstract
The application of biogas as a low-priced substrate for the production of ectoines constitutes an opportunity to decrease their production costs and to enhance the viability of anaerobic digestion. The influence of operational conditions on CH4-biogas biodegradation and on ectoines production yields was assessed in continuous pilot bubble column bioreactors. The rise in biomass concentration from 1 to 3 g L−1 resulted in a decrease in the specific ectoine content from 42 ± 8 to 30 ± 4 mgectoine gVSS−1. The concentration of Cu2+ and Mg2+ did not impact process performance, while the use of ammonium as N source resulted in low CH4 biodegradation and ectoine yields (13 ± 7 mgectoine gVSS−1). The increase in CH4 content from 4.5 to 9 %v·v−1 enhanced CH4 removal efficiency. Process operation at NaCl concentrations of 3 %w·w−1 instead of 6 %w·w−1 decreased the ectoine yield to 17 mgectoine gVSS−1. Finally, Methylomicrobium buryatense was identified as the dominant species.