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Halophiles produce stable enzymes under extreme conditions. The scant information about chitinolytic haloarchaea led us to conduct the present study in order to isolate and screen native halophilic archaea with chitinolytic activity and to optimize the enzyme production conditions. Among 500 haloarchaeal strains isolated from water samples from different hypersaline lakes of Iran, five strains showed chitinolytic activity. Based on biochemical, morphological and molecular analyses, we established that all five potent strains belonged to the genus Natrinema. Besides, observing chitinase function in culture media, through an additional molecular test the presence of the chitinase gene in chitinase-producing strains was also confirmed by PCR amplification. Compared with other potent strains, Natrinema sp. strain BS5 showed significant chitinase production. The production of chitinase in strain BS5 accompanied growth, started at the logarithmic phase and increased to its maximum level at the beginning of the stationary phase. Maximum chitinase production was obtained at 37˚C, pH 7.5, 3 M NaCl and 1% colloidal chitin. The strain BS5 showed 38%, 30%, 24% and 28% decreases in enzyme production at 40˚C, pH 8, 3.5 M NaCl and 0.5% substrate, respectively. This strain was able to produce the enzyme in NaCl 4 M and in the absence of MgCl2 and MgSO4. This study revealed the strong potential of the genus Natrinema to produce chitinase at high salt concentrations without Mg2+ requirement.

Phenols are toxic products derived from a wide range of industrial activities and the entry of these contaminants into the environment is seriously hazardous for both human and aquatic ecosystems. This study presents the use of a phenol-degrading consortium surrounded in an innovative "Small Bioreactor Chambers" (SBCs) along with biostimulation for phenol bioremediation from contaminated groundwater. To investigate the effect of biostimulation, synthesized-calcium peroxide (Ca02) nanoparricies were applied. The phenol-degrading consortium, was successfully isolated froni a water well located in Iran. The highest growth rate and phenol degradation of the ph100-consortium were observed at 15 °C and pH 7.5 in the presence of 500 mg·L-1 of powdered CaO2 and 100 mg·L-1 of phenol as a sole source of carbon. Next-generation sequencing (NGS) analysis of the consortium revealed that Proteobacteria and Bacteroidetes with 75.3% and 16.2% relative abundance were the dominant phyla in the ph100-consortium, respectively. Experimental results indicated that 100% of the contaminant (100 mg·LF) was successfully removed from groundwater using encapsulated CaO2 within 60 days with the negligible negative impacts on the microbial population. Furthermore, the highest biodegradation percentage were achieved during incubation of SBCs a medium supplemented with 500 mg·L-1 CaO2 Powder in 25th days of experiment. These results provide certain evidence for a successful simultaneous application of biostimulation and bioaugmentation processes through SBCs for contaminated water treatinent. [ABSTRACT FROM AUTHOR]