Screening and isolation of halophilic bacteria producing extracellular hydrolytic enzymes from salterns of the protected ecosystem Khnifiss Lagoon (Morocco)

ABSTRACT

Aims@#The present study was aimed to determine the diversity of the halophilic and halotolerant bacteria with hydrolase activities from salterns of the protected ecosystem Khnifiss lagoon (Morocco).@*Methodology and results@#Bacteria were isolated from sediment samples collected at five hypersaline sites on three different growth media supplemented with various concentrations of NaCl. Thirty bacterial isolates were identified using the 16S rDNA sequencing method. Physiological characterization was examined on Columbia agar with different concentrations of NaCl and pH values and incubated at different temperatures. Enzymatic activities were tested in submerged cultures with appropriate substrates. A total of 246 halophilic bacterial isolates from the salines of the protected ecosystem of Khnifiss lagoon in the south of Morocco were able to produce different hydrolases (cellulases, amylases, DNases, lipases and proteases). Furthermore, the majority of the isolates were classified as moderately halophilic bacteria that grew optimally between 5% and 15% of NaCl, and they adapted to other extreme conditions than salt: some cases tolerated a pH range of 4.5 to 9.4, as well as a temperature range of 10 to 50 °C. The 16S rDNA sequencing and phylogenetic analysis results indicated that most of the bacteria isolated from the salt marshes studied belong to the genus Bacillus.@*Conclusion, significance and impact of study@#Phenotypic and phylogenetic characterization of halophilic and halotolerant bacteria isolated from the salines of the protected ecosystem of Khnifiss lagoon has shown great diversity. Screening of hydrolytic enzymes produced by these bacteria suggests that the salines of the Khnifiss lagoon are a rich source of technologically interesting bacteria.