I want to ask about decolorization activity of bacteria using uv-vis spectrophotometer.This is a project of other and I want to know why control is not zero and minus result can also be used?
In this project,bacteria is used to decolorize molasses wastewater and use molasses containing nutrient broth to grow bacteria and incubate for 7days.
In this case,bacteria in molasses containing nutrient broth(day 0) is used as control by using uv-vis spectrophotometer and shows result of 1.23(e.g) and measure other bacterial broth daily.
In this case,I want to know is there is need to set up contro is zero?When I check bacterial growth rate in LB broth,I used LB broth as control and resolution is zero(I understand the condition is different but I want to know).
Please explain me if you have answer.
Hi, I think it's possible to calculate the decolorization activity of molasses by using the the rate of decrease in color intensity with the progression of baterial culture. and here you don't need an extra control for it. Just start taking your OD values(better,after removing the solids with centrifugation) with the start of culture( as zero time) once or twice a day, depending on the growth rate of your bacteria. Try to decide the log growth phase where the bacteria will grow exponentially. In this range you will get the maximum growth rate and hence the highest decolorization rate, by dividing the difference of OD values over a particular period of time, by the time difference (in hr. )in the log growth range. The decolorization rate = {(OD t1 - OD t2) / ( t2 - t1) }. If you further divide this rate by ODt1, then you will get the specific rate of decolorization (udecol) as follows: {(OD t1 - OD t2) / ( t2 - t1).ODt1. If decolorization proceeds linearly but inversely with the bacterial growth, then the inverse of the specific rate of decolorization, will give you the specific growth rate of your bacteria(umax). That's it. Good luck.
Thank for advice Tapan Kumar Mazumder....In here,is there any other reason to centrifuge except removing solids?
Can I also show data by percentage of decolorization(% decolorization=100(Co -Ct)/Co
Co is the initial concentration (control) and Ct is the concentration at time t.)?
Thank you very much..
Hi May, thank you for rensponding. Centrifugation is for removing solids (baterial cells and any other precipitating materials due to possible pH shift (if any) as the culture proceeds.
Yes, you may express the decolorization in percent, if the conditions remain the same. Good luck.
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