- Email: [email protected]
Hydrodynamic characteristics of microcapsules in a liquid–solid fluidized bed used for bioartificial liver
Abstracts / Journal of Biotechnology 136S (2008) S140–S143
S143
II4-P-008
II4-YP-009
Beauvericin produced by an endophytic fungus Fusarium redolens isolated from Dioscorea zingiberensis and its antibacterial activity
Hydrodynamic characteristics of microcapsules in a liquid–solid fluidized bed used for bioartificial liver
Peng 1 ,
Xiaobo Huang 1,2,∗ , Jianzheng Wang 1,2 , Ying Zhang 1 , Wei Wang 1 , Xiaojun Ma 1,∗
Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China 2 Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
1 Laboratory of Biomedical Material Engineering and Department of Science and Technology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, PR China 2 Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
E-mail address: [email protected] (L. Zhou).
E-mail address: [email protected] (X. Huang).
Microorganisms, in particular fungi, are known as a rich source of novel and unique antimicrobial compounds. Interest in endophytic fungi as potential producers of biological active products has increased in the last decade. One compound coded as Fr01 was separated from an endophytic fungus Fusarium redolens Dzf2 (accession number DQ44621) (Xu et al., 2008) from rhizomes of the traditional Chinese medicinal plant Dioscorea zingiberensis by bioassay-guided fractionation, and was identified as beauvericin by spectroscopic and physical methods to be a cyclic hexadepsipeptide which showed strong and broad antibacterial activity. The median effective inhibitory concentration (IC50 ) values of beauvericin against the six test bacteria (i.e. Bacillus subtilis, Staphylococcus haemolyticus, Pseudomonas lachrymans, Agrobacterium tumefaciens, Escherichia coli and Xanthomonas vesicatoria) were between 18.45 and 70.41 g/ml by a 96-well microplate broth dilution-MTT assay (Langfied et al., 2004). This is the first report of beauvericin fractionation and purification from fungal endophyte F. redolens Dzf2 isolated from D. zingiberensis. The obtained results provide promising information for the potential use of endophytic F. redolens Dzf2 for the biological role in its host plant protection as well as beauvericin production as antibacterial.
This study examined the hydrodynamic characteristics of APA microcapsules (Alginate-Poly-Lysine-Alginate) in a liquid–solid fluidized bed used for bioartificial liver. A detailed knowledge of hydrodynamic behavior of microcapsules is the first essential step for the correct design and operation of the fluidized bed (Francesc and Carles, 1995; Wu et al., 2003). The hydrodynamic properties include particle densities, terminal settling velocities, drag coefficient, and minimum fluidization velocities for immobilized cell beads of various particle sizes (Nicilella et al., 1999; Hermanowicz and Ganczarczyk, 1983). From experimental measurements of the single particle terminal settling velocity, the corresponding drag coefficient was found to be larger than that of a smooth, rigid sphere whereas to be in agreement with that of a elastic sphere. In addition, the drag coefficient–Reynolds number, velocity–voidage, and expansion index–Reynolds number relationships observed in our experiments were compared with the published results. Our experimental findings were inconsistent with the predictions made from previous correlations because of the difference of particles in physical characteristics (Ro and Neethling, 1990). Thus, new correlations describing the above-mentioned relationships were suggested. For multiparticle systems, the correction factor, f(ε), is a function of Reynolds number as well as Archimedes, and depends strongly on the bed voidage(ε). A new simple relation was developed to predict easily the voidage value from 0.45 to 0.90 at 945 < Ar < 13753. Furthermore, all the data were calculated by the means of the proposed equation and compared to the experimental measurements. A satisfactory accordance between experimental and calculated curves was observed.
Xu 1,∗ ,
Zhao 1 ,
Lijian Jianglin Jianyong Wu 2 , Ligang Zhou 1
Yongfu
Huang 1 ,
Youliang
1
Acknowledgements This work was co-financed by the grants from the 973 program of China (2006CB101901) and National Natural Science Foundation of China (30470038). Reference Langfied, R.D., Scarano, F.J., Heitzman, M.E., Kondo, M., Hammond, G.B., Neto, C.C., 2004. Use of a modified microplate bioassay method to investigate antibacterial activity in the Peruvian medicinal plant Peperomia galioides. J. Ethnopharmacol. 94, 279–281. Xu, L., Zhou, L., Zhao, J., Li, J., Wang, J., 2008. Fungal endophytes from Dioscorea zingiberensis rhizomes and their antibacterial activity. Lett. Appl. Microbiol. 46, 68–72.
doi:10.1016/j.jbiotec.2008.07.304
Reference Francesc, G., Carles, S., 1995. Fluidized-bed bioreactors. Biotechnol. Prog. 11, 479–497. Hermanowicz, S.W., Ganczarczyk, J.J., 1983. Some fluidization characteristics of biological beds. Biotechnol. Bioeng. 25, 1321–1330. Nicilella, C., van Loosdrecht, M.M.C., Felice, R.D., Rovatti, M., 1999. Terminal settling velocity and bed-expansion characteristics of biofilm-coated particles. Biotechnol. Bioeng. 62, 62–70. Ro, K.S., Neethling, J.B., 1990. Terminal settling velocity of bioparticles. Res. J. Water Pollut. Control Fed. 62, 901–906. Wu, J.Y., Chen, K.C., Chen, C.T., Hwang, S.C.J., 2003. Hydrodynamic characteristics of immobilized cell beads in a liquid–solid fluidized-bed bioreactor. Biotechnol. Bioeng. 83, 583–594.
doi:10.1016/j.jbiotec.2008.07.305
S143
II4-P-008
II4-YP-009
Beauvericin produced by an endophytic fungus Fusarium redolens isolated from Dioscorea zingiberensis and its antibacterial activity
Hydrodynamic characteristics of microcapsules in a liquid–solid fluidized bed used for bioartificial liver
Peng 1 ,
Xiaobo Huang 1,2,∗ , Jianzheng Wang 1,2 , Ying Zhang 1 , Wei Wang 1 , Xiaojun Ma 1,∗
Department of Plant Pathology, College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193, China 2 Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong, China
1 Laboratory of Biomedical Material Engineering and Department of Science and Technology, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, PR China 2 Graduate School of the Chinese Academy of Sciences, Chinese Academy of Sciences, 457 Zhongshan Road, Dalian 116023, China
E-mail address: [email protected] (L. Zhou).
E-mail address: [email protected] (X. Huang).
Microorganisms, in particular fungi, are known as a rich source of novel and unique antimicrobial compounds. Interest in endophytic fungi as potential producers of biological active products has increased in the last decade. One compound coded as Fr01 was separated from an endophytic fungus Fusarium redolens Dzf2 (accession number DQ44621) (Xu et al., 2008) from rhizomes of the traditional Chinese medicinal plant Dioscorea zingiberensis by bioassay-guided fractionation, and was identified as beauvericin by spectroscopic and physical methods to be a cyclic hexadepsipeptide which showed strong and broad antibacterial activity. The median effective inhibitory concentration (IC50 ) values of beauvericin against the six test bacteria (i.e. Bacillus subtilis, Staphylococcus haemolyticus, Pseudomonas lachrymans, Agrobacterium tumefaciens, Escherichia coli and Xanthomonas vesicatoria) were between 18.45 and 70.41 g/ml by a 96-well microplate broth dilution-MTT assay (Langfied et al., 2004). This is the first report of beauvericin fractionation and purification from fungal endophyte F. redolens Dzf2 isolated from D. zingiberensis. The obtained results provide promising information for the potential use of endophytic F. redolens Dzf2 for the biological role in its host plant protection as well as beauvericin production as antibacterial.
This study examined the hydrodynamic characteristics of APA microcapsules (Alginate-Poly-Lysine-Alginate) in a liquid–solid fluidized bed used for bioartificial liver. A detailed knowledge of hydrodynamic behavior of microcapsules is the first essential step for the correct design and operation of the fluidized bed (Francesc and Carles, 1995; Wu et al., 2003). The hydrodynamic properties include particle densities, terminal settling velocities, drag coefficient, and minimum fluidization velocities for immobilized cell beads of various particle sizes (Nicilella et al., 1999; Hermanowicz and Ganczarczyk, 1983). From experimental measurements of the single particle terminal settling velocity, the corresponding drag coefficient was found to be larger than that of a smooth, rigid sphere whereas to be in agreement with that of a elastic sphere. In addition, the drag coefficient–Reynolds number, velocity–voidage, and expansion index–Reynolds number relationships observed in our experiments were compared with the published results. Our experimental findings were inconsistent with the predictions made from previous correlations because of the difference of particles in physical characteristics (Ro and Neethling, 1990). Thus, new correlations describing the above-mentioned relationships were suggested. For multiparticle systems, the correction factor, f(ε), is a function of Reynolds number as well as Archimedes, and depends strongly on the bed voidage(ε). A new simple relation was developed to predict easily the voidage value from 0.45 to 0.90 at 945 < Ar < 13753. Furthermore, all the data were calculated by the means of the proposed equation and compared to the experimental measurements. A satisfactory accordance between experimental and calculated curves was observed.
Xu 1,∗ ,
Zhao 1 ,
Lijian Jianglin Jianyong Wu 2 , Ligang Zhou 1
Yongfu
Huang 1 ,
Youliang
1
Acknowledgements This work was co-financed by the grants from the 973 program of China (2006CB101901) and National Natural Science Foundation of China (30470038). Reference Langfied, R.D., Scarano, F.J., Heitzman, M.E., Kondo, M., Hammond, G.B., Neto, C.C., 2004. Use of a modified microplate bioassay method to investigate antibacterial activity in the Peruvian medicinal plant Peperomia galioides. J. Ethnopharmacol. 94, 279–281. Xu, L., Zhou, L., Zhao, J., Li, J., Wang, J., 2008. Fungal endophytes from Dioscorea zingiberensis rhizomes and their antibacterial activity. Lett. Appl. Microbiol. 46, 68–72.
doi:10.1016/j.jbiotec.2008.07.304
Reference Francesc, G., Carles, S., 1995. Fluidized-bed bioreactors. Biotechnol. Prog. 11, 479–497. Hermanowicz, S.W., Ganczarczyk, J.J., 1983. Some fluidization characteristics of biological beds. Biotechnol. Bioeng. 25, 1321–1330. Nicilella, C., van Loosdrecht, M.M.C., Felice, R.D., Rovatti, M., 1999. Terminal settling velocity and bed-expansion characteristics of biofilm-coated particles. Biotechnol. Bioeng. 62, 62–70. Ro, K.S., Neethling, J.B., 1990. Terminal settling velocity of bioparticles. Res. J. Water Pollut. Control Fed. 62, 901–906. Wu, J.Y., Chen, K.C., Chen, C.T., Hwang, S.C.J., 2003. Hydrodynamic characteristics of immobilized cell beads in a liquid–solid fluidized-bed bioreactor. Biotechnol. Bioeng. 83, 583–594.
doi:10.1016/j.jbiotec.2008.07.305