Fermentation – what a broad topic. People think that most fermentation types are different from each other and they really are not. Fermentation is the production of a product in a tank by usually a mono culture (but not always – Belgium ales, kombucha, etc) be it, fungi, bacteria, algae or yeast. Some have unique aspects, like totally anaerobic fermentation, which is really susceptible to oxygen. But, if you know the particulars of the organism, the basic process is not that different.
The big trick, with most fermentation processes are understanding the what the product is and what parameters (micro-organism biochemistry) are needed to produce it. These are considered the parameters of the process. For example, there are many bacterial enzymes, such as alpha-amylase, which are produced by starving the culture for carbon (discussed in papers such as Regulatory factors affecting alpha-amylase production in bacillus licheniformis. ). Knowing the fermentation parameters is important as is what was discussed in 3 previous posts, cleanliness and contamination – B. cereus about contamination – part 1.
An example of dealing with process parameters: long fermentation times can have issues with contamination. The longer the process time, the more susceptible the process is. This is where understanding the process and the micro-organism’s characteristics can help define the proper parameters. For example, I performed a 7 day fermentation to produce an enzyme I was interested in studying. The fungus I was studying was grown at a low pH (~pH4.0) to help prevent contamination. Since I understood the growth and biochemical characteristics of the organism in question, it was easy to determine the best way to alleviate possible contamination and this was by lowering the pH of the initial fermentation broth. This helped to relieve any possible contamination issues. This is just one example of how understanding the parameters can bring you to a successful fermentation.
If you need help with fermentation design, scale-up, or contamination issues, GeoMetrick Enterprises can help.
David Slomczynski, Ph.D; GeoMetrick Enterprises