An exoelectrogenic consortia isolated from a microbial electrolysis cell (MEC) for H2 production

An exoelectrogenic consortia isolated from a microbial electrolysis cell (MEC) for H2 production

Abstracts / Journal of Biotechnology 136S (2008) S290–S344 V1-O-128 Enzymatic hydrolyzation of chitin by an enzyme mixture Hyun-Chul Jung ∗ , Gyung-H...

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Abstracts / Journal of Biotechnology 136S (2008) S290–S344

V1-O-128 Enzymatic hydrolyzation of chitin by an enzyme mixture Hyun-Chul Jung ∗ , Gyung-Hyun Jo, Ro-Dong Park Department of Agricultural Chemistry, Chonnam National University, Gwangju 500-757, South Korea

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the columbic efficiency using this exoelectrogenic consortia can reached 80% which is three times higher than that using sewer sludge. Meanwhile, the DGGE analysis showed community structure of this exoelectrogenic consortia is much more simple than that of sewer sludge. So the exoelectrogenic consortia might provide a more proper and effective model on the study of community structure in MEC system.

E-mail address: [email protected] (R.-D. Park). Previously, it was studied that culture supernatant of Aeromonas sp. GJ-18 contained N-acetyl-d-glucosaminidase and N,N -diacetylchitobiase (KuK et al., 2005). Also N-acetyl-dglucosaminidase and chitinase activities were screened from wheat bran and these enzyme were further purified to homogeneity in this lab (Ju and Park, 2008). For a higher enzymatic hydrolysis of chitin, five kinds of enzyme mixtures composed of different ratio of enzyme amount from wheat bran (5.7 U/ml, W) and GJ-18 (7 U/ml, G) were tested. Three kinds (W/G ratio of 5/15, 10/10 and 15/5) of enzyme mixtures almost completely hydrolyzed the substrate ␣-swollen chitin after 3 days of incubation at 45 ◦ C. Wheat bran extract and GJ-18 supernatant hydrolyzed the substrate by 23% and 87%. When the amount of wheat bran extract increased in the enzyme mixture, yield of GlcNAc decreased but yield of chitobiose increased.

References Liu, H., Gort, S., Logan, B.E., 2005. Electrochemically assisted microbial production of hydrogen from acetate. Environ. Sci. Technol. 39, 4317–4320. Liu, W.Z., Wang, A.J., Ren, N.Q., Zhao, X.Y., Liu, L.H., Yu, Z.G., Lee, D.J., 2008. Electrochemically assisted biohydrogen production from acetate. Energy Fuels 22, 159–163.

doi:10.1016/j.jbiotec.2008.07.1869 V1-Y-004 A new method for microbial breeding by atmospheric-pressure, non-equilibrium discharge plasmas Li-Yan Wang 1,∗ , Guo Li 2 , Hong-Xin Zhao 1 , Sen Wang 2 , He-Ping Li 2 , Cheng-Yu Bao 2 , Xin-Hui Xing 1 1

References Ju, W.T., Park, R.D., 2008. Purification and characterization of N-acetyl-Dglucosaminidase from Wheat bran. Master degree article. Chonnam National University, Korea. KuK, J.H., Jung, W.J., Jo, G.H., Kim, Y.C., Kim, K.Y., Park, R.D., 2005. Selective preparation of N-acetyl-d-glucosamine and N,N -diacetylchitobiose from chitin using a crude enzyme preparation from Aeromonas sp. Biotechnol. Lett. 27, 7–11.

doi:10.1016/j.jbiotec.2008.07.1868 V1-O-129 An exoelectrogenic consortia isolated from a microbial electrolysis cell (MEC) for H2 production Aijie Wang 1,2,∗ , Dan Sun 2 , Nanqi Ren 1,2 , Lihong Liu 2 , Wenzong Liu 2 , Haoyi Cheng 2 1

State Key Lab of Urban Water Resource and Environment, Harbin Institute of Technology, China 2 School of Environmental and Municipal Engineering, Harbin Institute of Technology, Harbin, China E-mail address: [email protected] (A. Wang). It is well known that microbial electrolysis cell (MEC) was first developed by Liu et al. (2005) for hydrogen production. However, till now, little information presents the remarkable bacteria that function in a microbial electrochemical assisted hydrogen production reactor, especially, the function of different kinds of bacterial flora. In this study, a medium contained poorly crystalline Fe(III)-oxide was used to enrich exoelectrogenic consortia based on a serial dilution method. Using this method, we obtained a smallest functional unit from a double-chamber MEC inoculated with sewer sludge (Liu et al., 2008). This exoelectrogenic consortia can completely reduce 100 mmol poorly crystalline Fe(III)-oxide using acetate as the sole electron donors and form Fe3 O4 after 7 days cultivation, while this exoelectrogenic consortia did not grow on acetate in absence of Fe(III). When this exoelectrogenic consortia was inoculated into a mediator-less MFC fed with acetate as sole electron donor, it produced electricity at higher current density (375 mA/m2 ) than sewer sludge under the same conditions. And in one batch cycle (10 days),

Department of Chemical Engineering, Tsinghua University, Beijing 100084, China 2 Department of Engineering Physics, Tsinghua University, Beijing 100084, China E-mail addresses: [email protected] (L.-Y. Wang), [email protected] (H.-P. Li).

Effective and stable microbial mutation breeding is of great importance in biotechnology, especially for the microorganisms with highly complicated metabolic networks. Most of the traditional breeding methods have more or less shortcomings, such as low efficiency, low stability and safety (Schutze et al., 1998; Zhang et al., 2006). To overcome these problems, in this paper, we studied a new microbial breeding method by using atmospheric pressure, nonequilibrium discharge plasmas (APNEDPs). The APNEDPs consists of high concentrations of reactive species at low gas temperature and at atmospheric pressure without any requirements of vacuum systems, and can be expected to be potentially applied in microbial mutation breeding and other biotechnological fields. For developing the new breeding technology by APNEDPs, we investigated the plasma’s effect on single nucleotide, oligonucleotide and plasmid DNA (Li et al., in press). The results clearly showed that the plasma could destroy the DNA and break the DNA chain into segments. The APNEDPs were also used to mutate some industrial microorganisms, such as Streptomyces avermitilis, Methylosinus trichosporium, and so on. The results showed that the APNEDP-based microbial breeding method could easily form mutants with high mutation frequency and high genetic stability. Acknowledgements This work was supported by the National Key Technologies R&D Program (2006BAE01A-08-05), the Natural Science Foundation of Beijing (3083021) and the project sponsored by Beijing Municipal Science & Technology Commission (Z07000200540705). References Li, G., Li, H.-P., Wang, L.-Y., Wang, S., Zhao, H.-X., Sun, W.-T., Xing, X.-H., Bao, C.-Y., 2008. Genetic effects of radio-frequency, atmospheric-pressure glow discharges with helium. Appl. Phys. Lett. 92, in press.