• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1138-1149
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• 2017

The use of microalgal biomass is an interesting technology for the removal of heavy metals from aqueous solutions owing to its high metal-binding capacity, but the interactions with bacteria as a strategy for the removal of toxic metals have been poorly studied. The goal of the current research was to investigate the potential of Burkholderia tropica co-immobilized with Chlorella sp. in polyurethane discs for the biosorption of Hg(II) from aqueous solutions and to evaluate the influence of different Hg(II) concentrations (0.041, 1.0, and 10 mg/l) and their exposure to different contact times corresponding to intervals of 1, 2, 4, 8, 16, and 32 h. As expected, microalgal bacterial biomass adhered and grew to form a biofilm on the support. The biosorption data followed pseudo-second-order kinetics, and the adsorption equilibrium was well described by either Langmuir or Freundlich adsorption isotherm, reaching equilibrium from 1 h. In both bacterial and microalgal immobilization systems in the co-immobilization of Chlorella sp. and B. tropica to different concentrations of Hg(II), the kinetics of biosorption of Hg(II) was significantly higher before 60 min of contact time. The highest percentage of biosorption of Hg(II) achieved in the co-immobilization system was 95% at pH 6.4, at 3.6 g of biosorbent, $30{\pm}1^{\circ}C$, and a mercury concentration of 1 mg/l before 60 min of contact time. This study showed that co-immobilization with B. tropica has synergistic effects on biosorption of Hg(II) ions and merits consideration in the design of future strategies for the removal of toxic metals.

• 한국약용작물학회지
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• 제13권1호
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• pp.1-5
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• 2005

적변삼은 인삼에서 흔히 볼 수 있으며, 농가에 커다란 경제적 손실을 주지만, 아직까지 주원인에 대해서는 밝혀지지 않았다. 본 연구는 적변삼의 발생원인을 밝히기 위하여 적변삼과 내생 세균과의 연관성을 검토하였다. 인삼의 내생 세균 밀도는 정상 인삼의 경우 $0.96{\sim}1.5{\times}10^2cfu/g\;fw$에 불과하였으나 적변이 심한 경우는 $0.37{\sim}5.1{\times}10^7\;cfu/g\;fw$로 정상 인삼에 비하여 밀도가 매우 높았다. 적변삼에서 분리한 31개 균주는 적변정도의 차이는 있지만 적변을 유발하였다. 적변과 관련이 있는 세균은 대부분이 그람 음성균이었다. 적변을 유발하는 세균을 세균학적 특성과 16S rDNA의 염기서열 분석에 의해 동정한 결과 Agrobacterium tumefaciens, A. rhizogenes, Burkholderia phenazinium, Ensifer adharens, Lysobacter gummosus, Microbacterium Iuteolum, M. oxydans, Pseudomonas marginalis, P. veronii, Pseudomonas sp., Rhizobium leguminosarum, R. tropica, Rhodococcus erythropolis, Rh. globerulus, Variovorax paradoxus의 세균으로 동정되었다. 따라서 인삼적변의 발생은 내생세균의 침입 및 증식에 기인한 것으로 추정된다.