Isolation Of Butanol-producing Bacteria And Its Metabolism By-products Influence On Fermentation

With the reduction of fossil fuel and the increasing pollution, the energy crisishas already become a global problem. To find new and renewable clean energy,researchers from the global are actively exploring. Initially, people pay their focuson bio-ethanol, and have achieved certain results. However, with the developmentof science and technology, on bio-ethanol, there are many defects, and can not meetthe requirements of the automotive industry for fuel. Compared with traditional thebio-energy-ethanol, butanol has the higher value-added product, and it is moresuitable for automotive and easy to storage and transport, and because of the wideuse, butanol has higher value-added than ethanol, which make the research on itgradually become popular. However, because biological meause to produce butanolis not productive, and has long fermentation cycle, and the strain is easy todeteriorate, and so on. Therefore, one butanol production strains S10has beenisolated, and the optimization of culture conditions and metabolite regulationexperiment have finished. The main results are as follows:Through isolating from soil, one butanol production strain S10has been found.Through analyzing this strain by molecular measure, the sequence of its16S rDNAhas been known, and it is a1535bp long sequence. Nucleotide blast using the NCBIdatabase sequence alignment showd the strain S10belongs to Clostridium spp.Through morphological observation and physiological and biochemicalidentification, supplemented by the Neighbor-Joining phylogenetic tree analysis, thestrains were tentatively named C. roseum S10. For the best culture conditions ofstrain S10, three factors, which affect strain production of butanol most, wasidentified by the Plaekett-Burman experiment. Then these three factors wereoptimized by response surface, to determine the best formulation of the medium,and the production has improved from4.063g/L to4.204g/L.In order to improve butanol production, organic acids were added to themedium optimized to adjust the metabolic flow. The optimum time to addingorganic acids was determined to late exponential growth phase by the experiment ofadding acids in different time. After using response surface optimization, theoptimum concentration was identified—sodium butyrate2.57g/L and no sodiumacetate, and the production has reached5.808g/L,38.15%more the origin.