Linear fitting study on OD values and the number of two facultative anaerobic live bacteria

摘要

With the decrease of conventional energy, the development and utilization of bioethanol became a hot topic. Among many microorganisms that have been exploited for ethanol production, Yeast and Zymomonas mobilis have been intensively studied. The yield and quality of bioethanol directly depended on the activity and bacterial counts of this two, which was measured by the optical density (OD). In this paper, the relationship between OD values, and the number of Yeast and Zymomonas mobilis. After Yeast and Zymomonas mobilis were activated, 6.5mL sterilizated saline were adding to agar slant respectively. Then lml mixed bacterial liquid was diluted to 2.0, 3.4, 3.8,4.2, 4.6 and 5.0ml, in which the counts of Yeast and Zymomonas mobilis were determined with the method of dull colony notation. Two linear regression equations were obtained, one was Y1=0.166X+0.777 (R2= 0.956),whereX1 was the OD460 value, and Y1 was the number of viable cells(× 106 / ml). The other one was Y2= 0.147X2+0.137 (R2=0.984) , where X2 was the OD600 value, and Y2 was the number of viable cells(x 106 / ml). The bacterial counts of Yeast and Zymomonas mobilis can be got quickly and accurately by measuring the OD values, calculating from the two equations above.