Hi Alex, welcome to the group and good luck with the job.
Probably the only way to mount that turntable will be something resembling a lathe-headstock, although a large roller-ring bearing may suffice if money is no object.
In Engineering it is mandatory to present all of the known facts in order that others may help with a problem. Just giving the load figure and nothing else is as useful as just telling us the color you would like it finish up. Do some research here and you will find that in excess of 70% of ALL first inquiries, the following responses were for more detail and a sketch or picture.
You may as well learn to start out as you need to be in order to become a good, competent and useful Engineer. Good communication is beyond essential, it is mandatory in Engineering.