Résumé
The strain Acidiphilium cryptum DX1-1 producing PHB was irradiated respectively by UV and Co60 to raise PHB production. The results indicated that the effect of UV better than using Co60. One strain of the UV mutagenized called UV60-3 has the highest PHB production yield, showing final PHB concentra- tion of 28.56 g/L, 1.45 times higher than that of original strain. FT-IR spectroscopy analysis shows that the polymers obtained from the strain DX1-1 have the same IR spectra of standard PHB. Further research about the best appropriate C/N ratio of the mutant was done. The optimum ratio of C/N was about 3.76, the final PHB concentration reaches to 30.57 g/L.
Résumé
Reverse transcriptase-PCR experiments suggest that the two clusters of genes potentially involved in the oxidation of reduced sulfur compounds are organized as operons in strain of the acidophilic, chemolithoautotrophic bacterium Acidithiobacillus ferrooxidans ATCC 23270, the two clusters of genes including such the ORF of putative sulfate-thiosulfate-molybdate binding proteins, the ORF of putative thiosulfate: quinone oxidoreductase and the ORF of the rhodanese-like protein (P21). Bioinformatic analyses have predicted the possible promoters sequences and the possible +1 start site of transcription for the doxDA operons.
Résumé
Microalgae biodiesel can solve these problems currently of plants materials,such as:shortage of arable land,impact of climate change for production and to lead high crop prices and so on.Constructing "engineered microalgae" through transgenic technology,the microalgae have capacity of high growth,shorter periods of growth and several times higher oil production than terrestrial plants.Furthermore,sea water can be as its natural medium for industrial production.The advantages of microalgae biodiesel,current status and progress of researches on engineered microalgae as well as product technologies of microalgal biodiesel was introduced.
Résumé
Metal sulfides are chemically attacked by Fe~ 3+ and H~+, resulting in the formation of elemental sulfur via polysulfides or thiosulfate pathway. Elemental sulfur may aggregate and even form a layer on the metal sulfide surface, which will inhibit leaching metals from the sulfides minerals. Elimination of inert elemental sulfur in a typical acidic environment can exclusively be by way of oxidation of acidophilic sulfur-oxidizing bacteria, such a way includes the attachment, transport and oxidation process of elemental sulfur by acidophilic sulfur-oxidizing bacteria. On the basis of analysis on the pertinent researches, the molecular mechanism of sulfur elimination by the acidophilic bacteria is far away from elucidated, and to attain that target, there are still much work to be done for elucidating the molecular mechanism on the attachment, transport and oxidation process of elemental sulfur by the acidophilic sulfur-oxidizing bacteria.