I used to make kombucha & it is alkaline and full of probiotics but a big hassle. So I did an experiment. I got a bottle of blueberry & pomegranite juice or else used some raspberry juice from frozen raspberries. I put in some Sundown probiotics, also some sugar just to make sure that the little prob. guys got plenty to eat. In a few days the filler from the probiotics was floating at the top and easy to remove. The drink was no longer sweet but sour like kombucha. Put the mixture in a relatively warm and dark place for 3-4 days. When it is no longer sweet at all, it is ready. If you cap it tightly you will get fizzies (maybe too much, enough to pop the top) but that means acid & acid is bad for your teeth - very bad.

How much sugar? How many probiotics capsules? Any other kinds of juices that work? You'd have to experiment. I used about 3 hp tsp of sugar for 1 qt personally. Just guessing. I added 2 of one kind of probiotic and 1 of another just to be on the safe side! One of the probiotics was just lactobacillus, the other had 2 billion or so of various different kinds of probiotics.

You can also find ways on the net to easily make a probiotic drink with Vitacoco, but I found the juice way to be less expensive. You really don't even need to use total juice as long as you add the sugar. I added lots of water to the juice. The colored "water" looks and seems more palatable but I suspect just sugar & plain water would work as well, depending on how much sugar you use and how many probiotics you use.


After experimenting, as above, I found this link from Springer.com:
Abstract
In present investigation, two Lactobacillus isolates, viz. L. plantarum and L. acidophilus, were observed to be able not only to survive but to utilize fruit juices for their cell synthesis, as indicated by a decrease in fruit sugar and pH, and increase in acidity. L. acidophilus was found to consume the sugar at a faster rate than L. plantarum, although the fall in sugar and pH and increase in acidity was faster during the first 24 h and became a little slower during the next 48 h, which could be due to the accumulation of too much acid during the initial 24 h of fermentation. Still, both cultures were found to be able to survive in fermented juices with high acidity and low pH. Therefore, it could be concluded that such probiotic-fortified fruit juices could certainly be exploited as a medium for the delivery of probiotics, and could be used as a functional healthy beverage to promote better health and nutrition of the population, especially for those who are allergic or intolerant to milk-based products.

After I did this experiment I saw a link at springer.com about scientists in India using fruit juice to make probiotic drinks.