16s rDNA based microbial diversity analysis of eleven acid mine drainages obtained from three Chinese copper mines

Eleven acid mine drainage （AMD） samples were obtained from southeast of China for the analysis of the microbial communities diversity, and the relationship with geochemical variables and spatial distance by using a culture-independent 16S rDNA gene phylogenetic analysis approach and multivariate analysis respectively. The principle component analysis （PCA） of geochemical variables shows that eleven AMDs can be clustered into two groups, relative high and low metal rich （RHMR and RLMR） AMDs. Total 1691 clone sequences are obtained and the detrended correspondence analysis （DCA） of operational taxonomic units （OTUs） shows that, ~,-Proteobacteria, Acidobacteria, Actinobacteria, Cyanobacteria, Firmicutes and Nitrospirae are dominant species in RHMR AMDs. In contrast, a-Proteobacteria, fl-Proteobacteria, Planctomycetes and Bacteriodetes are dominant species in RLMR AMD. Results also show that high-abundance putative iron-oxidizing and only putative sulfur-oxidizing microorganisms are found in RHMR AMD. Multivariate analysis shows that both geochemical variables （r=0.429 3, P=-0.037 7） and spatial distance （r=0.321 3, P=-0.018 1） are significantly positively correlated with microbial community and pH, Mg, Fe, S, Cu and Ca are key geochemistry factors in shaping microbial community. Variance partitioning analysis shows that geochemical variables and spatial distance can explain most （92%） of the variation.

Isolation and Genetic Analysis of Halophilous Bacteria from Marine Sediment Collected at Tianjin Port, China

[Objective] Marine sediment from Tianjin Port has a extremely high salinity.The bacteria which live in such habitats have evolved distinct physiological,metabolic,and morphological characteristics to survive.The objective of this study is to identify all the specific salt-tolerant characteristics and the genetic evolution of the bacteria in the sediment.[Methods] In this study,the total DNA of sediment from Tianjin Port was extracted,and 16S rDNA was used to conduct an analysis of the fauna of sediment bacteria. We also isolated sediment bacteria using beef extract-peptone media with seven different NaCl concentrations (0,0.5%,2%,5%,10%,15%,and 20%),aiming to analyze the dominant species of halophilous bacteria under different salinities.[Results] 1) With each stepwise increase of salinity from 0.5% to 20%,the total number of isolated bacterial colonies decreased.14 strains of bacteria were identified and classified by the16S rDNA sequencing analysis.Of these,four could tolerate 0~2% salinity,four could tolerate 0~5% salinity,one could tolerate 0~15% salinity,and one tolerated within the full 0~20% salinity range.Further four strains were only able to tolerate within a few narrow salinity ranges.such as 5%~10%,10%~15%,10%~20% and 15%~20%;2) The quantity of bacteria strains that can be isolated from the marine sediment decreased with the increase of salinity. Also, the Shannon wiener index and species richness index of marine sediment bacteria decreased significantly from 5% salinity.However,there were no significant differences in the species evenness index;3) When the salinity was 0~10%,the dominant species was Bacillus.When the salinity was 15%, Halomonas was the dominant species.When the salinity was 20%,there were no significant differences in the proportions of these species.[Conclusion] Our results showed that some bacteria could tolerate living conditions with high salinity,and we even found a species which can tolerate a wide range of salinities (0~20%).In further study,it would be valuable to analyze these bacteria's unique physiological and biochemical functions that allow them to adapt to environments with high salinity.It can provide theories to promote the development of microbial population resources in marine sediment and the reclaimation of salinized soil by salt tolerant microorganisms.

Isolation and characterization of deodorizing bacteria for organic sulfide malodor

Strain Jll screened out from different odor origins can efficiently degrade methyl mercaptan and ethanethiol whereas has no ability to remove dimethyl sulfide. The results indicated that the strain Jll breaks only the C-SH bond. The optimum temperature and pH of Jll are 20—30℃ and 6.0—8.3 respectively. A systematic identification method—16S rDNA gene sequence comparison, for deodorizing bacteria was carried out. The 16S rDNA gene sequence analysis of strain Jll showed the highest level of 97% homology to Rape rhizosphere.

Biosynthesis of raw starch degradingβ-cyclodextrin glycosyltransferase by immobilized cells of Bacillus licheniformis using potato wastewater

The study was sought to enhance the synthesis of thermal stableβ-cyclodextrin glycosyltransferase(β-CGTase)using potato wastewater as a low-cost medium and assess the degree to which it is efficient for industrial production ofβ-cyclodextrin(β-CD)from raw potato starch.Thermophilic bacteria producingβ-CGTase was isolated from Saudi Arabia and the promising strain was identified as Bacillus licheniformis using phylogenetic analysis of the 16S rRNA gene.Alginate-encapsulated cultures exhibited twice-fold ofβ-CGTase production more than free cells.Scanning electron microscopy(SEM)of polymeric capsules indicated the potential for a longer shelf-life,which promotes the restoration of activity in bacterial cells across semi-continuous fermentation ofβ-CGTase production for 252 h.The optimal conditions forβ-CGTase synthesis using potato wastewater medium were at 36 h,pH of 8.0,and 50°C with 0.4%potato starch and 0.6%yeast extract as carbon and nitrogen sources,respectively.The purified enzyme showed a specific activity of 63.90 U/mg with a molecular weight of∼84.6 kDa as determined by SDS-PAGE analysis.The high enzyme activity was observed up to 60°C,and complete stability was achieved at 75°C.High levels of activity and stability were shown at pH 8.0,and the pH range from 7.0–10.0,respectively.The enzyme has an appreciable affinity for raw potato starch with a Km of 5.7×10−6 M and a Vmax of 87.71μmoL/mL/min.β-CD production was effective against 25 U/g of raw potato starch.The outcomes demonstrated its feasibility to develop a fermentation process by integrating the cost-effective production ofβ-CGTase having distinctive properties forβ-CD production with ecofriendly utilization of potato wastewater.

Isolation and Phylogenetic Analysis of Halophilic Archaeon AJ6

Halophilic archaeon AJ6 was isolated and purified from the Altun Mountain National Nature Reserve of the Xinjiang Uygur Autonomous Region.Strain AJ6 is a Gram-negative rod whose size is 0.2–0.6 by 1.6–4.2μm,wherein a few cells are globular.The optimum salt concentration for its growth is 20%NaCl and 0.6%Mg^(2+),and the optimum pH is 6.0–7.0.Morphological,physiological,and biochemical characteristics of strain AJ6 were observed.The 16S rRNA encoding gene(16S rDNA)sequence of strain AJ6 was amplified by PCR,and its nucleotide sequence was determined subsequently.“Clustalw”and“PHYLIP”software bags were used to analyze the 16S rDNA sequence;the homology was compared,and then the phylogenetic tree was established.The results indicate that strain AJ6 is a novel species of the genus Natrinema.The GenBank accession number of the 16S rDNA sequences of strain AJ6 is AY277584.