Related Experiment Video
Updated: May 9, 2026

Determination of Microbial Extracellular Enzyme Activity in Waters, Soils, and Sediments using High Throughput Microplate Assays
Published on: October 1, 2013
Phosphatase activity and specific methanogenic activity in an anaerobic reactor treating sludge from a brackish
Xuedong Zhang1, Rui B Ferreira, Henri Spanjers
1Faculty of Civil Engineering and Geosciences, Department of Water Management, Sanitary Engineering Section, Delft University of Technology, Stevinweg 1, 2628 CN Delft, The Netherlands. x.zhang@tudelft.nl
Abstract:
Anaerobic treatment of high salinity sludge from marine/brackish recirculation aquaculture systems is potentially limited by inhibition of enzymatic activities and cell lysis resulting from high osmotic pressures. To further address these limitations the following investigations were conducted: effect of salinity on phosphatase activity (PA), soluble microbial products (SMP) production, and presence of extracellular polymeric substances (EPS); effect of iron (III) chloride (FeCl3) on PA and specific methanogenic activity (SMA); effect of addition of the compatible solute glycine betaine (GB) and potassium on PA, as well as on SMP and EPS production, all under saline conditions. The results show that salinity has different effects on PA of anaerobes under starvation and feeding conditions. FeCl3 increased the SMA of the sludge by 22.5% at 100 mg FeCl3/L compared with a control group (0 mg FeCl3/L). Furthermore, results of analysis of variance tests show that betaine increased the polysaccharide content of EPS and polypeptide content of SMP. However, addition of 1 mM potassium chloride did not show a significant effect on EPS and SMP composition. In conclusion, anaerobic digestion of salty sludges from a brackish aquaculture recirculation system may not be negatively affected by FeCl3 addition to concentrate waste streams, whereas GB boosts the production of SMP and EPS.
More Related Videos
08:43Aerobic Biodegradation Testing of Materials Using a Natural Marine Seawater Inoculum and Closed Loop Respirometer
Published on: October 24, 2025
15:19Development of Sulfidogenic Sludge from Marine Sediments and Trichloroethylene Reduction in an Upflow Anaerobic Sludge Blanket Reactor
Published on: October 15, 2015
Related Concept Videos
Metabolism of Chemolithotrophs
Microbial Bioremediation of Hydrocarbons
Microbes and Methanogenesis
Overview of Archaea
Microbial Bioremediation of Plastics
Microbial Bioremediation of Uranium