Enhancing carboxylic acid yields from duckweed by acidogenic digestion

In this study, a series of laboratory batch experiments were executed to determine the best operating conditions (i.e., temperature and pH) to maximize carboxylic acid production from duckweed during acidogenic digestion by mixed anaerobic cultures. Batch reactors (300 mL working volume) were fed with duckweed to achieve a total solids content of 25 g/L, and were operated under mesophilic (35 ºC) or thermophilic (55 ºC) conditions at pH 5.3 or 9.2. The dominant microbial taxa under different conditions were also identified. The highest duckweed-tocarboxylic acid conversion of 332 mg/g (mg acetic acid per gram total solids) was observed under basic mesophilic conditions with 25 g/L solid loading. The superior performance observed was attributed to microbial bioconversion, augmented by chemical pretreatment under the specified operating conditions. These findings suggest that duckweed is a technically feasible alternative feedstock for the production of advanced biofuel precursors.