Mangrove Sediment Samples Research Articles

PAH-degrading microbial consortium and its pyrene-degrading plasmids from mangrove sediment samples in Huian, China

PAH-degrading microbial consortium and its pyrene-degrading plasmids were enriched from the sediment samples of Huian mangroves. The consortium YL showed degrading abilities of 92.1%, 87.6%, 92.3%, and 95.8% for pyrene, fluoranthene, phenanthrene, and fluoene at 50 mg l −1 after 21 days incubation, respectively. The dynamics of pH changes in the cultures was consistent with that of PAH concentration change. Bacillus cereus Py5 and Bacillus megaterium Py6 were isolated from the consortium and observed consuming 65.8% and 33.7% of pyrene (50 mg l −1) within three weeks, respectively. The enriched Escherichia coli DH5α cells containing the plasmids of YL were demonstrated to degrade 85.7% of the original pyrene concentration at the 21st day.

Micromonospora rifamycinica sp. nov., a novel actinomycete from mangrove sediment

An actinomycete strain, AM105(T), that produces rifamycin, was isolated from mangrove sediment samples collected from the South China Sea. The strain showed closest 16S rRNA gene sequence similarity to Micromonospora matsumotoense (98.0%). Chemotaxonomic characteristics of the isolate coincided with members of the genus Micromonospora. The value of DNA-DNA relatedness to M. matsumotoense (53.6%) and phenotypic differences from phylogenetically related Micromonospora species indicated that this isolate belongs to a novel species, for which the name Micromonospora rifamycinica sp. nov. is proposed. The type strain is AM105(T) (=CGMCC 4.2495(T)=DSM 44983(T)).

An alkaline protease from Bacillus circulans BM15, newly isolated from a mangrove station: characterization and application in laundry detergent formulations

An investigation on the properties of an alkaline protease secreted by Bacillus circulans BM15 strain isolated from a mangrove sediment sample was carried out in order to characterize the enzyme and to test its potency as a detergent additive. The protease was purified to apparent homogeneity by ammonium sulphate precipitation and was a 30-kDa protease as shown by SDS-PAGE and its proteolytic activity was detected by casein zymography. It had optimum activity at pH 7, was stable at alkaline pH range (7 to 11), had optimum temperature of activity 40°C and was stable up to a temperature of 55°C after incubation for one hour. Hg(2+), Zn(2+), Co(2+), and Cu(2+)completely inhibited the enzyme activity, while Ca(2+), Mg(2+), K(+) and Fe(3+) were enhancing the same. The serine protease inhibitor PMSF and metal chelator EDTA inhibited the activity of this protease while the classic metalloprotease inhibitor 1, 10 phenanthroline did not show inhibition. The enzyme was stable in SDS, Triton-X-100 and H(2) O(2) as well as in various commercial detergents after incubation for one hour. The extracellular production of the enzyme, the pH and temperature stability and stability in presence of oxidants, surfactants and commercial detergents suggest its possible use as a detergent additive.

Characterization of alkaline protease from Vibrio fluvialis strain VM10 isolated from a mangrove sediment sample and its application as a laundry detergent additive

An extracellular alkaline protease producing strain was isolated from the sediment sample collected from a mangrove station in Cochin estuary and was identified as Vibrio fluvialis. The protease produced was purified to apparent homogeneity by ammonium sulphate precipitation and was determined to be a 33.5-kDa protease as shown by SDS-PAGE and its activity detected by casein zymography. This protease had optimum activity at pH 8 and temperature 55 °C. This was stable at alkaline pH range and up to a temperature of 50 °C, after incubation for 1 h. Hg 2+ and Cu 2+ showed complete inhibition of the enzyme activity, while Co 2+, Ca 2+ and Fe 3+ were enhancing the activity. This protease was inhibited by the serine protease inhibitor PMSF and the metal chelator EDTA but not by the classic metalloprotease inhibitor 1,10 phenanthroline. The protease was found to be stable in presence of compounds like H 2O 2, SDS, and Triton-X-100 and also in some commonly used commercial detergents tested. The extracellular production of the enzyme, the pH and thermal stability, and the stability in presence of oxidants, surfactants and commercial detergents, suggest its possible use as a laundry additive.