Study On The Selectivity Of Methanotrophs On Methanol And Ethanol

Methanotrophs have been specialized, it has a wide range of potential applications in Bio-catalys, Bio-remediation,CH4 Controls, Sensors and so on. Espiecially Methanotrophs as molecular recognition elements methanol or ethanol sensor have high selectivity, and it doesn't interfere from other alcohol. The mechanism should be dehydrogenase high select to alcohol, but the high selectivity mechanism is not clear. Address these issues, our group select strains ME25 and ME45, using pure culture, determination of growth, determination of dissolved oxygen, determination of dehydrogenase activity and isozyme analysis to study the law about ME25 and ME45 select to methanol and ethanol.The cell growth results showed, ME25 and ME45 cultured into methanol medium, the two strains growth fastest when methanol concentration was 1%(v/v), the two strains cultured into ethanol medium, the strain ME25 growth fastest when methanol concentration was 1%(v/v), the strain ME45 growth fastest when methanol concentration was 2%(v/v).The methanol cultured strains cultured in the methanol and ethanol medium, the ethanol cultured strains cultured in the methanol and ethanol. It found out the methanol cultured strains cultured in ethanol, the lag phase was longer than the strains' cultured in methanol. The ethanol cultured strains cultured in methanol, the lag phase was longer than the strains'cultured in ethanol. Dissolved oxygen determination showed, ME45 which is cultured into ethanol medium has a strong signal on the response to ethanol, but it has not signal on the response to methanol. ME25 which is cultured into methanol medium has a strong signal on the response to methanol, but it has not signal on the response to ethanol. Dehydrogenase activity analysis showed, with ethanol as the substrate, methanol cultured strains'enzyme activity was far lower than with methanol as the substrate. On the contrary, with methanol as the substrate, ethanol cultured strains'enzyme activity was far lower than with ethanol as the substrate. Isozyme analysis showed that the methanol cultured strains'metabolism of methanol zymogram was different from the ethanol cultured strains'. The effects of metallic ions to alcohol dehydrogenase results showed, Cu2+,Hg2+,Cd2+,Fe3+ inhibit the alcohol dehydrogenase, and Fe3+ had a smaller inhibition. Ca2+ had an advance action to the alcohol dehydrogenase.These results indicated that from cell growth, dissolved oxygen consumer, dehydrogenase activity anlysis and Isozyme analysis showed ME25 and ME45 have selectivity to methanol and ethanol. The methanol cultured strains give priority to use methanol and have a higher methanol dehydrogenase activity. The ethanol cultured strains give priority to use ethanol and have a higher ethanol dehydrogenase activity. The metabolic enzymes for methanol and ethanol were inducible enzyme. It can tolerance different metallic ions inhibit and control. It is important to understand methanotrophs sensor select methanol and ethanol.