Hi @ezynda3,
Welcome to the community forum 
Thanks for posting the question here.
In the current version there doesn’t appear to be an option to configure the mnemonic for the accounts being used: https://docs.openzeppelin.com/test-environment/0.1/getting-started#configuration
Additional features are being added as part of OpenZeppelin Test Environment – Roadmap Q2 2020
I will have to come back to you if this is an option.