Hyperledger Fabric is a permissioned distributed ledger framework for enterprises that allow developers to build blockchain-based applications and solutions. With its modularity, Fabric can cater to a wide range of industry use cases. It provides a unique approach to consensus algorithm that enhances performance at scale while maintaining privacy. 

Hyperledger Sawtooth blockchain supports both public and permissioned blockchain implementation, while Hyperledger Fabric only provides permissioned blockchain implementation. 

Hyperledger Sawtooth uses the Proof of Elapsed Time mechanism; on the other hand, Hyperledger Fabric uses the Kafka consensus algorithm. Unlike Hyperledger Fabric, Sawtooth supports Seth project, which means Ethereum based smart contracts can be migrated to the Sawtooth platform seamlessly. 

In a Hyperledger Sawtooth platform, either all the transactions are processed simultaneously or not at all processed. On the other hand, transactions are executed in batches of Kafka blocks in a Hyperledger Fabric platform. 

PBFT and PoET are two most common consensus algorithms supported by the Hyperledger Sawtooth platform.

• PBFT:
  It is a leader-based Hyperledger consensus mechanism which is non-forking and offers Byzantine Fault Tolerance (BFT). Since this algorithm is ideal for smaller consortium networks, it does not need open membership.
  
  
• PoET:
  PoET stands for Proof of Elapsed Time. It supports large distributed validator networks with the least resource consumption. You don’t need hardware to run PoET or Sawtooth.