Isolation And Identification Of Heavy Metal Resistant Bacteria From Deep-sea Sediments And Preliminary Study Of Chromate Reduction By Brevibacterium Sanguinis Strain NCD-5

Almost all types of microorganisms can be found in marine environment.. For the survival in high salt, high pressure, low-temperature, low-nutrition ,scarcity of light and other such extreme environmental conditions, they have developed special physiological and genetic characteristics, such as salt-tolerant, thermophilic, psychrophilic, barophilic,osmophiles, nitrogen fixation, nitrate reduction, heavy metal resistance . Study on marine heavy metal resistant bacteria now were mainly focused on those isolated from hydrothermal vents. In this report, heavy metal bacteria were isolated from deep sea sediments in the polymetallic nodule province of the Pacific. The research was concentrated on the diversity of heavy metal resistant bacteria and their resistance mechanisms.Through the two enrichments with 8 kinds of heavy metals in LB medium from deep-sea sediments, 280 isolates were obtained and 16S rDNA sequence showed all the isolates include 33 species of 16 genus, and identified to be : Bacillus pumilus,Bacillus cereus,Bacillus firmus,Bacillus megaterium,Bacillus mycroides,Bacillus mojavensis,Bacillus cibi,Bacillus sphaericus, Bacillus fusiformis,Bacillus hwajinpoensis,Bacillus vietnamensis,Advenella incenata,Alcanivorax dieselolei,Alcaligenes faecalis,Arthrobacter oxidans,Brachybacterium paraconglomeratum,Brevibacterium aureum,Brevibacterium sanguinis,Citricoccus alkalitolerans,Exiguobacterium aurantiacum,Halomonas meridiana,Halomonas venusta,Kocuria palustris , Kocuria erythromyxa , Microbacterium oxydans , Microbacterium oleovorans , Paracoccus marcusii , Planococcus maritirnus , Staphylococcus saprophyticus,Staphylococcus epidermidis,Virgibacillus dokdonensis,Virgibacillus pictruae. Based on the phylogenetic analysis resulte,the groups of Actinobacteria,Firmicutes,Proteobacteria were detected in the samples. Several bacteria were found in deap sea sediments and were the first time to be found to have abilities of heavy metal resistance, such as Advenella incenata strain Cr12 isolated from East Pacific and Brevibacterium sanguinis strain NCD-5 isolated from the south China Sea. Among all the bacteria, the most common species were in the genera of Bacillus with 231 isolates of 12 species,82.5 per cent of the whole isolates.Since they are isolated from all samples supplemented with 6 metals,they would not be ignored as a group of...