Interested to Buy Any Domain ? << Click Here >> for more details...
MICROBIOLOGICAL ENGINEERING - QUESTION 28.3 : In the calculation of the growth of bacteria, absorbance, A in spectrophotometry is used. According to Beer-Lambert Law, A = e x l x c where A is the absorbance of the solution (no unit), l is the distance of light travels through the solution (in cm), e is the molar absorptivity or the molar extinction coefficient [ in L / (mol.cm) ]. For a particular solute and fixed path length : As / Ao = Cs / Co where Ao is the observed signal for a known concentration Co, and As is the observed signal for a sample concentration Cs. (a) For a cell concentration of 560 cells / mL, a spectrophotometre gives an absorbance reading of 1.0. A mixture of concentration 3600000 cells / mL can be diluted in several operations, with each operation having a dilution of 1:20. How many dilutions should be made so that the concentration of this mixture can be calculated within a range of A = 0.0 to 1.0. (b) In another experiment, a sample tube of 1 cm in width is used. Let A = 0.06 and e = 0.0012 ml / (cell.cm). Find the cell concentration of the sample.
- 1 Answers
- 2430 Views
- I also Faced
- E-Mail Answers
Answer Posted / kangchuentat
MICROBIOLOGICAL ENGINEERING - ANSWER 28.3 : (a) Let Ao = 1.0, Co = 560 cells / mL, Cs = 3600000 cells / mL. By using the equation As / Ao = Cs / Co, then As = Ao x Cs / Co = 1.0 x 3600000 / 560 = 6428.57. For a dilution of 1:20, first stage dilution gives A = 6428.57 / 20 = 321.43, second stage dilution gives A = 321.43 / 20 = 16.07, third stage dilution gives A = 16.07 / 20 = 0.8, which is within a range of A = 0.0 to 1.0. Total stages of dilution needed = 3. (b) By using the equation A = e x l x c, then c = A / (e x l) = 0.06 / { [ 0.0012 ml / (cell.cm) ] x 1 cm } = 50 cells / mL. The answer is given by Kang Chuen Tat; PO Box 6263, Dandenong, Victoria VIC 3175, Australia; SMS +61405421706; chuentat@hotmail.com; http://kangchuentat.wordpress.com.
| Is This Answer Correct ? | 0 Yes | 0 No |
Post New Answer View All Answers
Hi. I have completed my masters in chemical engineering from M S University in year 2008 and now going to do MS Chemical engineering in Lamar University. I am planning to appear for interview in two weeks from now. What are the expected questions from VO regarding masters after masters ? and wat should i expect to give reply ? kindly give your suggestions. Thanks
Explain how can one determine if a particular solid can be fluidized as in a fluidized bed?
What are the uses of quicklime?
friends....i have been searching the model paper for HPCL officer trainee for chemical eng....tat apptitude section...if u people got any information regarding tat...please send me to my mail...my id is: maruthu.flower@gmail.com...pls send me wtever information u knew....thank u....
What are some of the consequences of an undersized kettle type reboiler?
What is carbon sequestration?
Explain what particle sizes are electrostatic precipitators used to remove?
What is the best way to control an oversized, horizontally oriented shell and tube steam heater?
How can hexavalent chromium be removed from aqueous waste streams?
Explain can large temperature differences in vaporizers cause operational problems?
What is an effective means of removing silicone from aluminum?
Can you pls tell me how to calculate the amphere rating of cable in case of three phase supply but all load is single phase
Corenuts technology interview questions
What are some guidelines for sizing a psv for a fire scenario on a vessel in a refinery service?
What are some factors to consider when trying choosing between a dry screw compressor and an oil-flooded screw compressor?
