• Title/Summary/Keyword: Bio-functional

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Bacillus subtilis as a Tool for Screening Soil Metagenomic Libraries for Antimicrobial Activities

  • Biver, Sophie;Steels, Sebastien;Portetelle, Daniel;Vandenbol, Micheline
    • Journal of Microbiology and Biotechnology
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    • v.23 no.6
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    • pp.850-855
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    • 2013
  • Finding new antimicrobial activities by functional metagenomics has been shown to depend on the heterologous host used to express the foreign DNA. Therefore, efforts are devoted to developing new tools for constructing metagenomic libraries in shuttle vectors replicatable in phylogenetically distinct hosts. Here we evaluated the use of the Escherichia coli-Bacillus subtilis shuttle vector pHT01 to construct a forest-soil metagenomic library. This library was screened in both hosts for antimicrobial activities against four opportunistic bacteria: Proteus vulgaris, Bacillus cereus, Staphylococcus epidermidis, and Micrococcus luteus. A new antibacterial activity against B. cereus was found upon screening in B. subtilis. The new antimicrobial agent, sensitive to proteinase K, was not active when the corresponding DNA fragment was expressed in E. coli. Our results validate the use of pHT01 as a shuttle vector and B. subtilis as a host to isolate new activities by functional metagenomics.

Monitoring of Chemical Changes in Explosively Puffed Ginsengvand the Optimization of Puffing Conditions

  • Yoon, Sung-Ran;Lee, Gee-Dong;Kim, Hyun-Ku;Kwon, Joong-Ho
    • Journal of Ginseng Research
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    • v.34 no.1
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    • pp.59-67
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    • 2010
  • Response surface methodology was used to predict the optimum conditions of explosive puffing process for ginseng. A central composite design was used to monitor the effect of moisture content and puffing pressure on dependent variables such as functional compounds (extract yield, crude saponin, acidic polysaccharide, and total phenolic content) and sensory properties. Correlation coefficients $(R^2)$ of models for crude saponin, acidic polysaccharide, and total phenolic content were 0.9176 (p<0.05), 0.9494 (p<0.05), and 0.9878 (p<0.001), respectively. Functional compounds increased with decreasing moisture content and increasing puffing pressure. Overall palatability was high at 15-20% moisture content and 98-294 kPa of puffing pressure. On the basis of superimposed contour maps for functional compounds and overall palatability of puffed ginseng, the optimum ranges of puffing conditions were 10-17% moisture content and 294-392 kPa puffing pressure.