Kombucha traditionally is made in a glass or porcelain fermenter. We would strongly recommend you to start in a similar mason jar or a pickle jar that is typically found in Indian kitchens. Tie it with a muslin cloth (or handkerchief) to prevent insects from dropping by.
As you scale your kombucha, we would recommend you to use either:
Conical fermenter: This allows you to rapidly clean the sediment without disturbing the SCOBY. Hence, you can ferment faster and scale up your enterprise. Another option is to ferment in a Corny Keg. These are inexpensive and allow you to produce very good quality natural carbonation. You can sell and transport in the kegs as well. This allows you to scale up fast.