Bioprocessing Part 1: Fermentation

Summary

This script delves into the fascinating world of fermentation, a biological process harnessed to produce a myriad of products, from dairy to pharmaceuticals. It explains how cells, be it bacteria or fungi, act as micro-factories to manufacture goods like yogurt, bread, and vaccines. The script outlines the fermentation lifecycle, from the lag phase to death phase, and provides an in-depth look at a green fluorescent protein (GFP) production process, detailing the preparation, monitoring, and harvesting steps within a bioreactor.

Takeaways

• 🍶 Fermentation is a widely used process for producing dairy, baked goods, beverages, and more by controlling the decomposition of food substances.
• 🌱 It involves the use of microorganisms such as bacteria, fungi, or specific cells from mammals, plants, or insects to manufacture products.
• 🧪 The process is initiated by selecting a cell type based on its ability to produce a desired product, then growing it in a nutrient-rich media.
• 🔬 Fermentation is a key upstream biotechnology process that occurs before recovery, purification, and packaging stages.
• 🌡️ Environmental factors like temperature, pressure, pH, and oxygen levels are closely monitored and controlled for optimal cell growth and product production.
• 📈 The growth of cells in fermentation typically follows a pattern with four phases: lag, exponential (log), stationary, and death.
• 🔄 The process involves scaling up from a small seed stock of cells to larger vessels, eventually reaching a production vessel or bioreactor.
• 🧪 Commercial-scale fermentation produces a vast array of products including amino acids, biopharmaceuticals, enzymes, food products, and vitamins.
• 🔬 The production of green fluorescent protein (GFP) is used as an example, where genetically modified E. coli is used to produce the protein as a biological marker.
• 🛠️ Equipment such as bioreactors, spectrophotometers, and glucose analyzers are essential for monitoring and controlling the fermentation process.
• 🔍 The harvested product, or broth, is then moved to downstream processes where the desired product is separated from the media and cells.

Q & A

What is fermentation and how is it used in various industries?

Fermentation is a biological process used to produce a wide array of products such as dairy, baked goods, and beverages. It involves the controlled breakdown of substances by microorganisms like bacteria, fungi, or specific cells from mammals, plants, or insects. This process is utilized in industries to manufacture products like amino acids, biopharmaceuticals, dyes, enzymes, food products, lipids, steroids, and vitamins.

How does fermentation work at a cellular level?

At a cellular level, fermentation is a process where cells, which can be bacteria, fungi, or specific cells from other organisms, are used to manufacture a product. These cells act as micro-factories, converting nutrients from the growth media into the desired product, which could be a naturally occurring chemical, a substance genetically altered to produce, or a metabolic waste product.

What are the different types of cells used in biotechnological fermentation?

In biotechnological fermentation, various types of cells are used, including bacteria for products like yogurt, buttermilk, and cheese; yeast, a fungus, for breads and alcoholic beverages; and mammalian cells for the production of some vaccines.

What is the role of media in fermentation?

Media in fermentation provides the necessary nutrients for the cells to grow and produce the desired product. It is a carefully formulated mixture that contains elements like nutrients, stabilizers, and sometimes antibiotics to protect the purity of the batch.

How is the fermentation process scaled up in industrial production?

The fermentation process is scaled up by starting with a small seed stock of cells in a minimal amount of media. As the cells grow and consume nutrients, they are gradually moved into larger vessels with more media. This process repeats until the cells reach a quantity sufficient for transfer into a production vessel, often referred to as a bioreactor or fermenter.

What are the key environmental factors that need to be monitored and controlled during fermentation?

During fermentation, key environmental factors that need to be monitored and controlled include temperature, pressure, pH, dissolved oxygen levels, and nutrient levels. These factors are critical to ensure optimal growth and product yield from the cells.

What is the typical lifecycle of a fermentation batch?

The typical lifecycle of a fermentation batch includes four phases: lag, where the cells adapt to the new environment; exponential or log, where cells divide at a constant rate; stationary, where the key nutrients are consumed, and the growth slows; and death, where more cells die than divide if the fermentation continues.

What is the role of IPTG in the GFP fermentation process?

In the GFP (Green Fluorescent Protein) fermentation process, IPTG (Isopropyl β-D-1-thiogalactopyranoside) is a biochemical inducer used to activate or turn on the expression of the GFP gene in the cells, leading to the production of GFP.

How is the quality of the fermentation process ensured?

The quality of the fermentation process is ensured through rigorous monitoring, control of the environment within the bioreactor, and adherence to standard operating procedures (SOPs). Sterilization of equipment and media is also crucial to eliminate unwanted microorganisms.

What happens to the fermented product after the fermentation process is complete?

After the fermentation process is complete, the product, referred to as broth, is harvested. This broth contains spent media and cells. It is then cooled, pumped into a broth tank, and labeled with relevant information. The broth will move downstream to the recovery process, where the cells are ruptured to release the product, which is then separated from other components.