Who builds the blockchain and processes transaction?

[svk]

How does it work in Bitshares? Who builds the blockchain and processes transaction if there is no mining? Is it possible to earn transactionfees by having  a transaction server running? Could someone please explain this in an easy way.

Bitshares uses Delegated Proof of Stake (DPOS), where a set of witnesses take turns to produce blocks. Witnesses are selected through stake-weighted voting, and there are currently 27 of them. The number is dynamic and depends on the votes being cast by shareholders.

http://cryptofresh.com/witnesses

https://bytemaster.github.io/bitshares/2015/01/04/Delegated-Proof-of-Stake-vs-Proof-of-Work/

[wolfram]

How does it work in Bitshares? Who builds the blockchain and processes transaction if there is no mining? Is it possible to earn transactionfees by having  a transaction server running? Could someone please explain this in an easy way.