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 Our main research objective is to transfer waste biomass into clean energy by taking use of microbial organism or microflora. The present research fields involve in (1) Studies on hydrogen production from a two step process of dark- and photo- fermentation of biomass; (2) Researches on the function and structure of the microflora.
Principal Investigator: Dr. Zhi-Hua Zhou, Professor. Email: zhouzhihua@sippe.ac.cn
Staff: Dr. Xing Yan, Research Assistant; Wei Xiao, Research Intern; Jun Zhang, Research Intern
Postdoctoral Fellow: Dr. Gen Zou
Graduate Students: Xin-Feng Li; Jun Zhang; Rui-Song Yu; Tong Liu; Ruo-Fan Wang; Liang Ma; Yong-Jun Wei; Chang-Li Qian
Graduated Student: Fang-Hua Liu, 2002 (PhD)
Improvement in Hydrogen Yield of a Photosynthetic Bacterial Strain by Genetic Manipulation
Photosynthetic bacteria evolve molecular H2 catalyzed by nitrogenase with nitrogen absent under illumination and parts of the evolved molecular H2 would be absorbed by uptake hydrogenase. nifA gene, encoding specific transcriptional activator for all other nif genes, controls the transcription of the genes for synthesis of nitrogennase. In this study, a genetic manipulating system was built for a Photosynthetic bacterial n, RS601. A mutant was obtained in which the gene coded for the small unit of uptake hydrogenase hupS was knocked out and nifA was over expressed. The hydrogen yield of the mutant increase 20% compared to that of the wild strain.
Discovery of Novel Cellulase Genes by Screening Metagenomic Library from Biogas Slurry
High efficiency of degradation of cellulose in a biogas digester indicates there might be abundance novel cellulase genes in the microbial community of the biogas slurry. However, the most of the microorganisms in the biogas slurry were uncultured, so it is difficult to obtain these novel cellulase genes through traditional approaches based on pure culture. In this study metagenomic methods were used to screening novel cellulase genes from the microbial community. Metagenomic DNA at high quality and high molecular weight (about 40kb) was extracted from the biogas slurry. The DNA was ligated to a fosmid vector and was then packaged and was used to transfect E coli cells. A metagenomic libray containing 1×105 clones was constructed. The clones containing genes of endoglucanase, or exoglucanse or β-D-glucanase or xylanase were selected by screening the library. Until now, 121, 341, 246 and 386 clones which showed activity of exoglucanse, endoglucanase, β-D-glucanase and xylanase were selected, respectively. Eight of the selected clones were sequenced and five new cellulase genes were discovered. The sequences of the four cellulase genes were matched to their nearest neighbor in Genbank at similarities from 45% to 62%, indicating these genes were novel. More novel cellulase genes were expected to be discovered from this metagenomic library.
Publications:
Tao Y, et al. and Zhou Z. (2008) Characteristics of a new photosynthetic bacterial strain for hydrogen production and its application in wastewater treatment. International Journal of Hydrogen Energy 33: 963-973. Zhou ZH, Sakaue D, Wu BY, Hogetsu T. (2007) Differentiation of Populations of the Pinewood Nematode Bursaphelenchus xylophilus between and within Pine Forests. Phytopathology 97: 304-310. Tao YZ, Chen Y, Wu YQ, He YL, Zhou ZH. (2007) High hydrogen yield from a two-step process of dark- and photo-fermentation of sucrose. International Journal of Hydrogen Energy 32: 200-206.
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