Bio-Succinic Acid Production from Palm Oil Mill Effluent Using Enterococcus gallinarum with Sequential Purification of Biogas

Bio-succinic acid production using microorganisms has been interesting as an environmentally friendly process. Palm oil mill effluent (POME) was considered as a cheap substrate to lower the cost of production. It was revealed that 2-fold diluted POME produced more succinic acid than undiluted and 5-fold diluted POME. In addition, the effects of various neutralizing agents on succinic acid production utilized to manage pH and CO2 supply indicated that the utilization of MgCO3 as a neutralizing agent produced succinic acid of 11.5 g/L with a small amount of by-product synthesis. Plackett-Burman Design (PBD) was used to screen the most significant nutrients for bio-succinic acid production from 2-fold diluted POME using E. gallinarum. From the Pareto chart, MgCO3 and peptone presented the highest positive effect on the production of succinic acid. In addition, Box-Behnken Design (BBD) was conducted to increase bio-succinic acid production. Experiments showed the highest production of succinic acid of 23.7 g/L with the addition of 22.5 g/L MgCO3 and 12.0 g/L peptone in 2-fold diluted POME. Moreover, the experiment of replacing MgCO3 with CO2 from biogas resulted in 19.1 g/L of succinic acid, simultaneously creating the high purity of biogas and a higher CH4 content.