|
In the 21st century, cleaner energy is the new requirements for our society. Hydrogen, renewable, safety and environmentally benign, is considered as one of the most promising future resources, so it has attracted widely attention in the whole world. Now, people concentrate their attentions on the development of hydrogen, and more and more researches have been focused on this field. Hydrogen production through bioconversion is highly prized for its feasibility and more marginal energy obtained by especially anaerobic fermentation which has many, advantages, such as desirable hydrogen production rate, mild conditions and controllable parameters.Bio-hydrogen technology has been research in this study, such as screening and identifying the strains producing hydrogen, the influence of mainly impact factors and the structure of the strain’s metabolic network. Hungate technique which has been widely used is adopted in this study. Four strains with higher efficiency are obtained from sludge which has been handled by different treatment, especially ES3, which has the most hydrogen production of 1804ml/L, and then ES3 is used as the object strain of the following research. After analyzed by its morphology, physiology and 16S rDNA gene sequence, it was found that the gene of the strain is 98% homologous to Enterobacteriaceace Bacterium M530. So the strain is named of ES3 for short and it status in microbial taxonomy is determined.After researching the growth feature of ES3, it was found that the best carbon source for ES3 is glucose, and the appropriate temperature is range from 34℃to 38℃. The incubation time of ES3 is short which only last for 10～14 hours. The key researches of this experiment are two principal factors, pH and reducing agent, the results shew that:the optimal pH value for hydrogen production is 5.8, and the amount of hydrogen production will be enhanced if a proper quantity of phosephate buffer is added to the culture medium,. How did L-cysteine affect the hydrogen production have also been considerated, the result shows that:when 300 mg/l of L-cysteine is added to the media, the hydrogen production reach the most value which is 1.29mol H2/mol Glu.Except for hydrogen and carbon dioxide in the fermentation broth, there are many by-productions in it. From the research we can know that:the mainly by-productions are 2, 3-butanediol, ethanol, acetic acid, succinic acid and lactic acid. According to the metabolites of ES3 and its production process, a metabolic network was structured in order to give a guideline in the following research.
|