The microbial composition of Kombucha culture depends on several factors. Whether it's handcrafted or commercially made, no kombucha will have the exact same composition of microbes; it varies, depending on temperatures (as close to only one degree can change the whole culture), geographic location, oygen levels in the air, quality of tea, water, etc. It has even been shown that using a different Kombucha "starter" (Kombucha liquid that is put in during the first fermentation) can cause the development of a different antioxydant activity, even if the bacteria culture and yeast did not change (Aloulou and al. 2012).
If you'd like to know more about Kombucha, please visit the different scientific articles cited down below.