Optimization of growth medium and procesing condition of acinetobacter sp as biological phosphorus removal for wastewater treatment in semi-industrial scale bioreactor

Abstract

Acinetobacter sp. has been reported previously in their role to enhance the removal of biological phosphorus and heavy metal when introduced in waste water treatment. This is an importance characteristics to be used in remediating the waste water instead of depend on naturally present of microbes. Therefore, high densities of Acinetobacter sp. to function in the bioremediation treatment are needed. The optimization of Acinetobacter sp. was carried out in shake flask for 24 hours cultivation using different carbon sources (glucose, sucrose, maltose, fructose and glycerol), nitrogen sources (yeast extract, soy powder, corn steep liquor, beef extract and peptone from casein) and phosphate salts (potassium monohydrogen phosphate). Total cell mass of 2.14 g L-1 was produced in un-optimized semi-defined medium using glucose as sole carbon source. Replacement of glucose with sucrose resulted in the 62.60% increase of cell mass production (3.48 g L-1). Yeast extract (20 g L-1) was demonstrated as the best nitrogen source based on the 172.89 % increase of cell mass (5.84 g L-1). Unfortunately, different concentration of phosphate salts did not show any differences in cell mass production. A combination of the optimized parameters resulted in 7.59 g L-1 of cell mass after 16 hours of cultivation. In conclusion, Acinetobacter sp. showed cell mass production rate of 0.23 g L-1 h-1 under un-controlled pH compared to controlled pH (0.12 g L-1 h-1).