Nutrient removal from the centrate of anaerobic digestion of high ammonium industrial wastewater by a semi-continuous culture ofArthrospirasp. andNostocsp. PCC 7413

摘要

The feasibility of the semi-continuous cultivation ofArthrospira(Spirulina) sp. andNostocsp. PCC 7413, using the centrate from the anaerobic digestion of wastewater from a seafood canning industry as a nutrient source, was assessed. Semi-continuous cultures were carried out in aerated tubular culture units of 250 mL by replacing a 10-20% of the volume with the centrate every 2 days. Growth, ammonium, and nitrate removal were monitored, as well as phycobiliprotein and protein production byArthrospirasp. and released exopolysaccharides production byNostocsp. PCC 7413. The ammonium removal efficiency byArthrospirasp. was 84.9 +/- 1.9% in a culture maintained with an ammonium concentration of 11.3 mM. Lower ammonium concentrations (4.9 mM) could be applied toNostocsp. PCC 7413, reaching similar relative removal efficiency (84.1%). Taking into account the high ammonium stripping that occurs at the high pH required inArthrospirasp. cultures, results indicate a better nutrient removal byNostocsp., althoughArthrospirasp. is more suitable for working at high ammonium concentrations. Since all the ammonium was removed during the first 24 h for both species, much lower residence time could be supported by the cultures. High concentrations of protein (2.5 +/- 0.2 mg mL(-1)), phycobiliprotein (allophycocyanin, 84.3 +/- 10.2 mg g(-1); phycocyanin, 73.7 +/- 7.7 mg g(-1)) were obtained byArthrospirasp. cultures. A high concentration of released exopolysaccharides (962.7 +/- 26.7 mg L-1) was also obtained forNostocsp. PCC 7413 when cultured in the anaerobic centrate. The results indicate the possibility of the use of filamentous cyanobacteria for the treatment of industrial effluents rich in ammonium, with different possibilities of valorization of the biomass produced.