Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent

This study investigated the removal of nitrogen and phosphorus from the effluent of a submerged anaerobic membrane bioreactor (SAnMBR) by means of a lab-scale photobioreactor in which algae biomass was cultured in a semi-continuous mode for a period of 42 days. Solids retention time was 2 days and a stable pH value in the system was maintained by adding CO2. Nitrogen and phosphorus concentrations in the SAnMBR effluent fluctuated according to the operating performance of the bioreactor and the properties of its actual wastewater load. Despite these variations, the anaerobic effluent proved to be a suitable growth medium for microalgae (mean biomass productivity was 234 mgl(-1) d(-1)), achieving a nutrient removal efficiency of 67.2% for ammonium (NH4+-N) and 97.8% for phosphate (PO4-3-P). When conditions were optimum, excellent water quality with very low ammonium and phosphate concentrations was obtained.This research project has been supported by the Spanish Research Foundation (CICYT, projects CTM2011-28595-C02-01 and CTM2011-28595-C02-02), whose support is gratefully acknowledged.Ruiz Martínez, A.; Martin Garcia, N.; Romero Gil, I.; Seco, A.; Ferrer, J. (2012). Microalgae cultivation in wastewater: nutrient removal from anaerobic membrane bioreactor effluent. Bioresource Technology. 126:247-253. https://doi.org/10.1016/j.biortech.2012.09.022S24725312

Characterization of the Exopolysaccharide Produced by Salipiger mucosus A3T, a Halophilic Species Belonging to the Alphaproteobacteria, Isolated on the Spanish Mediterranean Seaboard

We have studied the exopolysaccharide produced by the type strain of Salipiger mucosus, a species of halophilic, EPS-producing (exopolysaccharide-producing) bacterium belonging to the Alphaproteobacteria. The strain, isolated on the Mediterranean seaboard, produced a polysaccharide, mainly during its exponential growth phase but also to a lesser extent during the stationary phase. Culture parameters influenced bacterial growth and EPS production. Yield was always directly related to the quantity of biomass in the culture. The polymer is a heteropolysaccharide with a molecular mass of 250 kDa and its components are glucose (19.7%, w/w), mannose (34%, w/w), galactose (32.9%, w/w) and fucose (13.4%, w/w). Fucose and fucose-rich oligosaccharides have applications in the fields of medicine and cosmetics. The chemical or enzymatic hydrolysis of fucose-rich polysaccharides offers a new efficient way to process fucose. The exopolysaccharide in question produces a solution of very low viscosity that shows pseudoplastic behavior and emulsifying activity on several hydrophobic substrates. It also has a high capacity for binding cations and incorporating considerable quantities of sulfates, this latter feature being very unusual in bacterial polysaccharides