Answered

Welcome to Westonci.ca, where you can find answers to all your questions from a community of experienced professionals. Explore thousands of questions and answers from a knowledgeable community of experts ready to help you find solutions. Join our Q&A platform to connect with experts dedicated to providing accurate answers to your questions in various fields.

Serratia marcescens bacteria are used for the production of threonine. The maximum specific oxygen uptake rate of S. marcescens in batch culture is 4 mmol O2 g-1 h-1. It is planned to operate the fermenter to achieve a maximum cell density of 50 g l-1. At the fermentation temperature and pressure, the solubility of oxygen in the culture liquid is 8 × 10^-3 kg m^-3. The concentration of oxygen in the culture liquid is 0.5 × 10^-3 kg m^-3. At a particular stirrer speed, kLa is 0.17 s^-1.

Required:
Under these conditions, will the rate of cell metabolism be limited by mass transfer?

Sagot :

Answer:

The rate of cell metabolism is limited by mass transfer since the value of maximum cell concentration obtained (38 g/l) is lower than 50 g l-1, the value planed.

Explanation:

                                                     Data

kLa = 0.17/s

Solubility of oxygen =  8 × 10^-3 kg / m^3

The maximum specific oxygen uptake rate = 4 mmol O2 / g h.

Concentration of oxygen =  0.5 × 10^-3 kg/ m^3

**The maximum cell density = 50 g/l

___________________

The calculated maximum cell concentration:

xmax=  kLa · CAL*/ qo

CAL* is the solubility of oxygen in the broth and qo is the specific oxygen uptake rate

Replacing the data given

xmax= ( 0.17/s ) ·   (8 × 10^-3 kg / m^3)  /  4 mmol O2 / g h

4 mmol O2 / g h  to kg O2/ g s

[tex]4 \frac{mmol}{gh} \frac{1 gmol}{1000mmol}\frac{1h}{3600s}\frac{32 g}{gmol} \frac{1Kg}{1000g}[/tex]

= 3.56 x 10^-3 kg O2/ g s

So then,

xmax= ( 0.17/s ) ·   (8 × 10^-3 kg / m^3)  / 3.56 x 10^-3 o kg O2/ g s

xmax= 3. 8 x 10^4 g/ m^3   = 38 g/l

_____________________

We appreciate your visit. Our platform is always here to offer accurate and reliable answers. Return anytime. Thank you for your visit. We're committed to providing you with the best information available. Return anytime for more. Your questions are important to us at Westonci.ca. Visit again for expert answers and reliable information.