Understanding Recombinant Protein Production in High Cell Density Fermentation

High cell density fermentation is a powerful technique for producing recombinant proteins, where microorganisms are cultured in large quantities. In these systems, the recombinant protein of interest often represents a significant proportion of the total cellular protein. In this article, we will walk through the steps to calculate the concentration of recombinant protein produced in a high cell density fermentation system based on key parameters such as optical density (OD), dry cell weight, and protein content.

Problem Overview:

In this scenario, the recombinant protein is 20% of the total cellular protein. The final cell density is 80 OD, where 1 OD corresponds to 0.4 g of dry cell weight per liter. Additionally, 50% of the dry cell weight is total cellular protein. The goal is to determine the concentration of the recombinant protein in the fermentation broth.

Step-by-Step Calculation:

Step 1: Convert OD to Dry Cell Weight

Optical density (OD) is a commonly used measure of cell growth in microbial cultures. The given data states that 1 OD corresponds to 0.4 g of dry cell weight per liter.

To find the dry cell weight at 80 OD:

$$\text{Dry cell weight}=80\text{OD}\times 0.4\text{g/L/OD}=32\text{g/L}$$

Step 2: Calculate the Total Cellular Protein

The problem specifies that 50% of the dry cell weight is total cellular protein:

$$\text{Total cellular protein}=32\text{g/L}\times 50\%=16\text{g/L}$$

Step 3: Calculate the Recombinant Protein Concentration

The recombinant protein is 20% of the total cellular protein:

$$\text{Recombinant protein}=16\text{g/L}\times 20\%=3.2\text{g/L}$$

Conclusion:

The recombinant protein concentration in the fermentation broth is 3.2 g/L.

Final Answer:

• 2. 3.2 g/L

This process illustrates how to calculate recombinant protein concentration in high cell density fermentation using key growth parameters such as optical density, dry cell weight, and protein content. Understanding these calculations is crucial for optimizing fermentation processes in biotechnology applications.