Are Compatible Solutes Compatible with Biological Treatment of Saline Wastewater? Batch and Continuous Studies Using Submerged Anaerobic Membrane Bioreactors (SAMBRs)

Abstract

This study investigated fundamental mechanisms that anaerobic biomass employ to cope with salinity, and applied these findings to a continuous SAMBR. When anaerobic biomass was exposed to 20 and 40 g NaCl/L for 96 h, the main solute generated de novo by biomass was trehalose. When we separately introduced trehalose, N-acetyl-β-lysine and potassium into a batch culture a slight decrease in sodium inhibition was observed. In contrast, the addition of 0.1 mM and 1 mM of glycine betaine dramatically improved the adaptation of anaerobic biomass to 35 g NaCl/L, and it continued to enhance the adaptation of biomass to the salt for the next three batch feedings without further addition. No shift in archaeal microbial diversity was found when anaerobic biomass was exposed in batch mode to 35 g NaCl/L for 360 h, and no changes were found when glycine betaine was added. The dominant species identified under these conditions were Methanosarcina mazeii and Methanosaeta sp. The addition of 5 mM glycine betaine to a continuous SAMBR at 12 h hydraulic retention time (HRT), and operation in batch mode for 2 days can significantly enhance saline (35 g NaCl/L) synthetic sewage degradation. In addition, the injection of 1 mM of glycine betaine into a SAMBR for five subsequent days also significantly enhanced dissolved organic carbon (DOC) removal from sewage under these conditions. The main compatible solutes generated by anaerobic biomass after 44 days exposure to 35 g NaCl/L in a SAMBR were N-acetyl-β-lysine and glycine betaine. Finally, the addition of 1 mM glycine betaine to the medium was beneficial for anaerobic biomass in batch mode at 20 °C under saline and non saline conditions.

Enhancement of anammox activity by addition of compatible solutes at high salinity conditions

“…For instance, at salinity of 25 g/L, the SAA with the addition of 1 mM GB, trehalose and ectoine was 12.4, 11.8 and 10.9 mg N/gVSS/h and increased by nearly 59.0%, 51.3% and 39.7% over the control (7.8 mg N/gVSS/h), respectively. According to the theory put forward by Vyrides et al (2010), it can be inferred that GB may be the most easy to be transported through the membranes and absorbed by the anammox bacteria, followed by trehalose and then ectoine. Furthermore, 1 mM GB addition ( Fig.…”

“…Yerkes et al (1997) demonstrated that 1 mM of glycine betaine (GB), one of the CS, could create a positive effect on pure cultures of Methanosarcina and Methanosaeta under highly saline conditions. Vyrides et al (2010) found that methane produced during batch anaerobic digestion in salt toxicity level (35 gNaCl/L) was http://dx.doi.org/10.1016/j.biortech.2014.06.015 0960-8524/Ó 2014 Elsevier Ltd. All rights reserved. three times higher when GB was added.…”

Reactor performance and microbial community dynamics during aerobic degradation and detoxification of Acid Red B with activated sludge bioaugmented by a yeast Candida tropicalis TL-F1 in MBR

“…It is suggested that fungi may be effective bioaugmentation microorganisms for improving treatment efficiency and adaptability of conventional wastewater treatment consortia such as activated sludge. Meanwhile, though the problem on the loss of key microbes along with effluent ever limited the use of bioaugmentation, it has been resolved through the usage of immobilization technique or membrane to confine the key microorganisms in the bioreactors (J ez equel et al, 2005;Vyrides et al, 2010).…”

Sustainable Agro-Food Industrial Wastewater Treatment Using High Rate Anaerobic Process

“…Vyrides et al [79] indicated that glycine-betaine (GB), an organic compound, can cause antagonism against sodium toxicity. However, using GB to decrease sodium toxicity in commercial scale anaerobic digesters would be too costly [75].…”