What beneficial bacteria are in your kombucha starter? Have you ever heard of opening probiotic pills and adding to starter? Will the living bacteria continue to reproduce in my homebrewed kombucha? There were some particular strands I wanted to add.
Our test results show mostly Gluconacetobacter, gluconic acid, which is a form of acetic acid. The process of fermenting kombucha creates both alcohol and high levels of acid, both substances are likely to kill off the living bacteria in the pills you buy. If you have the specific strands of bacteria you want in pill form, I would continue to rely on the pills.
To add Lactobacillus to your kombucha fermentation, you can do the following: add cabbage juice to your brew when you start, or minced cabbage, making it lacto-fermented. You can toss the batch made from cabbage if it tastes bad, but the ongoing scoby/ batches will be boosted by the Lactobacillus strain.
One suggestion, you could ferment other things, if you are looking to create specific strains. Beet kvass is one option, it contains vitamins, dietary fiber, as well as naturally grown probiotics. Here is one method to make it: http://holisticsquid.com/beet-kvass-myth-busting/
Another option would be to make your own yogurt, when you purchase the starter commercially the strains present are codified.
Here is one linkto information, for those of you who are committed to reproducing your own probiotics at home (the last post on the list being the most relevant): https://www.quora.com/Can-I-culture-grow-my-own-probiotic-s-using-a-store-bought-capsule-using-a-medium-other-than-milk-yoghurt-ex-water
In conclusion, if you research the particular strands you want to reproduce, it is possible to find a better medium than kombucha to ferment and reproduce them at home, unless it is Lactobacillus, which can be included in kombucha.