title: Demonstration of sequential adaptation strategy for developing salt tolerance in bacteria for wastewater treatment: a study using Escherichia coli as model.
abstract: A wastewater isolate identified as Escherichia coli HPC781 was adapted for high salt concentration through sequential transfers in Luria Broth (LB). The cells were grown in LB with 5% sodium chloride (NaCl) and were analyzed for the acquired salt resistance network through gene expression profiles. Microarray studies revealed TCA, glyoxylate shunt and acetyl Co-A metabolism as key nodes for stress combat to arrive at compromised physiology. It also proposed that the cells were receiving signals from salt environment via OmpR-EnvZ two component systems and stress dependent general regulatory protein rpoH and rpoE. The salt adapted culture, when challenged with wastewater having additional 5% salt showed growth. The work represents a tactic to adjust biochemical network towards stress and reveals its applicability via real-time PCR measurement of genes in wastewater. The study proposes that the recycled biomass with an adaptation strategy could be applied for treatment of wastewater with high salt levels.
authors.affiliation: Environmental Genomics Division, National Environmental Engineering Research Institute (NEERI), CSIR Nagpur, India.
authors.forename: Sampada
authors.initials: S
authors.lastname: Puranik
authors.forename: Shraddha
authors.initials: S
authors.lastname: Shaligram
authors.forename: Vasundhara
authors.initials: V
authors.lastname: Paliwal
authors.forename: Dhananjay V
authors.initials: DV
authors.lastname: Raje
authors.forename: Atya
authors.initials: A
authors.lastname: Kapley
authors.forename: Hemant J
authors.initials: HJ
authors.lastname: Purohit
mesh_terms: D000220:Adaptation, Biological / Q000502:physiology*; D004926:Escherichia coli / Q000378:metabolism / Q000502:physiology*; D020869:Gene Expression Profiling; D006360:Heat-Shock Proteins / Q000378:metabolism; D046228:Microarray Analysis; D054712:Salinity; D012808:Sigma Factor / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D062065:Wastewater / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*
chemical_list: D006360:Heat-Shock Proteins; D012808:Sigma Factor; D062065:Wastewater; C069774:heat-shock sigma factor 32; C063202:sporulation-specific sigma factors