Isolation, identification and validation of the facultative fixed carbon and nitrogen bacteria: A type of microorganisms that can fix CO2 and N2 at the same time
一种能同时固定CO2和N2的微生物——兼性固CO2、N2菌的分离鉴定及其验证实验

Currently, greenhouse effect becomes more and more serious, and biological carbon-fixing, especially microbial biological carbon-fixing, can play a unique role in curbing the greenhouse effect. The N2-fixing microbial azotobacter and the CO2-fixing bacteria have been discovered for years. However, there is few report about microprganisms that can fix CO2 and N2 simultaneously while taking CO2 and N2 separately as microbial carbon and nitrogen sources. Such a microorganism was defined as facultative CO2 and N2-fixing bacteria in this study. A carbon and nitrogen-free medium was optimized by carbon-fixing medium and nitrogen-fixing medium. A strain of CO2 and N2 as the carbon source and nitrogen source, respectively, was isolated by a nitrogen and carbon-free culture medium and was labeled as HSJ. In addition, the HSJ's characteristics of carbon fixation enzyme activity and nitrogenase activity was determined. The HSJ with a carbon fixation enzyme specificity of cbbL gene stripe (cbbL in RubisCO genes) and nitrogen-fixing enzyme specificity of nifH gene stripe was detected by PCR and agarose gel electrophoresis. To testify fixation of CO2 and N2 in the air simultaneously with CO2 and N2 separately as the carbon and nitrogen sources, validation testing of the bacterium HSJ was carried out. The observation morphology and sequence analysis of 16S rDNA of the HSJ is subordinate to the strains of Streptomyces.