ABSTRACT
ABSTRACT An analysis of wastewater samples collected from different industrial regions of Egypt demonstrated dangerously high levels of nickel (0.27-31.50 mg L-1), chromium (1.50-7.41 mg L-1) and zinc (1.91-9.74 mg L-1) in the effluents. Alarmingly, these heavy metals are among the most toxic knownones to humans and wildlife. Sixty-nine Actinomycete isolates derived from contaminated sites were evaluated under single, binary, and ternary systems for their biosorption capacity for Ni2+, Cr6+ and Zn2+ from aqueous solutions. The results of the study identified isolates MORSY1948 and MORSY2014 as the most active biosorbents. Phenotypic and chemotypic characterization along with molecular phylogenetic evidence confirmed that the two strains are members of the Nocardiopsis and Nocardia genera, respectively. The results also proved that for both the strains, heavy metal reduction was more efficient with dead rather than live biomass. The affinity of the dead biomass of MORSY1948 strain for Ni2+, Cr6+ and Zn2+ under the optimized pH conditions of 7, 8 and 7, respectively at 40 °C temperature with 0.3% biosorbent dosage was found to be as follows: Ni2+ (87.90%) > Zn2+ (84.15%) > Cr6+ (63.75%). However, the dead biomass of MORSY2014 strain under conditions of pH 8 and 50 °C temperature with 0.3% biosorbent dose exhibited the highest affinity which was as follows: Cr6+ (95.22%) > Ni2+ (93.53%) > Zn2+ (90.37%). All heavy metals under study were found to be removed from aqueous solutions in entirety when the sorbent dosage was increased to 0.4%.
Subject(s)
Metals, Heavy/metabolism , Nocardia/classification , Nocardia/metabolism , Temperature , Time Factors , Water Pollutants, Chemical/metabolism , Biodegradation, Environmental , RNA, Ribosomal, 16S/genetics , Biomass , Metals, Heavy/toxicity , Adsorption , Egypt , Wastewater/microbiology , Hydrogen-Ion Concentration , Industrial Waste , Nocardia/isolation & purification , Nocardia/geneticsABSTRACT
Objective To explore cytotoxic secondary metabolites from a marine actinomycete Nocardiopsis sp .SCSIO 11492 .Methods Isolation and purification were carried out by column chromatography over silica gel ,Sephadex LH-20 ,and ODS structures of the isolates were identified mainly by NMR spectroscopic data .And cytotoxic bioassay was performed using MTT method .Results Five compounds were identified as 2′-deoxyadenosine (1) ,2′-deoxythymidine (2) ,2′-deoxyuidine (3) ,uridine (4) ,1-O-palmitoyl-3-d-galactosyl-sn-glycerol spongilipid (5) .Compound 5 exhibited weak cytotoxic activity with IC50 value of 10 .9 μmol/L .Conclusion Five compounds were obtained from a marine actinomycete Nocardiopsis sp .SCSIO 11492 .All five compounds were reported for the first time from this genus .Compound 5 could be the bioactive compound re-sponsible for the cytotoxic activity of Nocardiopsis sp .SCSIO 11492 .
ABSTRACT
The response of two marine actinomycetes such as Streptomyces sp. MADO2 and Nocardiopsis sp. MADO3 to osmotic stress in minimal medium M63 and in glycerol-asparagine medium (ISP5) was studied. The two strains were moderately halophilic and the behavior of the strain Streptomyces sp. MADO2 and Nocardiopsis sp. MADO3 towards the salt stress was varied depends on the media composition and the salinity concentration. The strain Streptomyces sp. was more sensitive to salt stress than Nocardiopsis sp. The growth of both Streptomyces sp. and Nocardiopsis sp. were inhibited at 1 M NaCl irrespective of the medium used. The Nocardiopsis sp. acquired osmoadaptation on ISP5 medium whereas the Streptomyces sp. showed poor growth on M63 medium. Glycine betaine (GB), proline and trehalose played a critical role in osmotic adaptation at high osmolarity whereas at low osmolarity they showed an inhibitory effect on the bacterial growth. The present findings confirmed that GB was the powerful osmoprotectant for Streptomyces sp. and Nocardiopsis sp. grown at 1 M NaCl both in M63 and ISP5 media.