Influence of culture conditions on the production of extracellular polymeric substances (EPS) by Arthrospira platensis

Abstract

Arthrospira platensis is a cyanobacterium that exhibits a large biotechnological interest at food industry because its high protein content, pigments, lipids and carbohydrates. The extracellular polymeric substances (EPS) are co-products of secondary metabolism that present thickening or gelling property. A 3-level factorial design was used to study the combined effect of different nitrate concentrations and photon flux density (PFD) to evaluate the biomass and EPS production by Arthrospira platensis. Characterization of the EPS produced the rheological behavior were also evaluated. The best result for biomass production was obtained at condition 6 (2 g.L-1 NaNO3 and 600 µE.m-2s-1) leading a biomass concentration of 1.292 mg.L-1. Condition 1 (0.25 g.L-1NaNO3 and 200 µE.m-2s-1) produce the major EPS content (111 mg.g-1) followed by condition 9 (2 g.L-1NaNO3 and 1000 µE.m-2s-1). Rheological studies performed for the product at 5 and 10g.L-1 concentrations revealed a dilute solution behavior.