I am working in microalgae and I have optimised their growth conditions in fermenter. But after 2 months, when I again growing the alga there is slow growth at same conditions. What would be the reason?
The main reason for slow growth of microorganisms at optimized conditions in a fermenter could be substrate limitation, where essential nutrients or substrates required for microbial growth are not present in sufficient quantities. Other factors like oxygen availability, pH, temperature, or the accumulation of inhibitory by-products can also influence microbial growth rates in a fermenter.
About growth of algae in fermentor,First you should check about contamination specially yeast.second its probably your carbohydrate resources is not enough for growth.
So, you grew it and optimized the conditions; then grew it again two months later with poor results. So something, such as contamination, has occurred. Also, check and be sure the bioreactor is working properly, and nothing is getting stuck.
Check that your inoculum (starter culture) is as much as the last time you grew it.
Yes, I have successfully optimized the process at larger scales, up to a 700 L bioreactor. Now, in flasks up to 5 L, it grows very well. I regularly check under the microscope and have not observed any contamination. However, when I transferring the inoculum to a 75 L bioreactor, it initially grows slowly, then enters a stationary phase, followed by another period of slow growth before ultimately stopping altogether. I have attempted three batches, and each follows a similar pattern of growth. There have been no changes in the medium composition or fermenter conditions. Additionally, I am growing it in parallel in flasks, where it grows well.
If you are sure about contamination,I would like to say about enough carbohydrate source again .next, maybe limited oxygen rate need to be optimize according to your algae species.then, its possible, it releated to fermentor design ,i mean mechanichal stimulation damage the cells and reduce the growth.finally you notice some micro algae are not suitable for growing in fermentor.good luck