Java-JWT use public and private keys from string (Scala)

Question

I'm building a server side application in scala which needs to create a JWT to communicate with a third party API.

Due to dependency reasons, I am using the Java JWT Library as opposed to a Scala equivalent.

The current infrastructure injects a string for the public and private keys among other bits of sensitive server configuration at run-time, so I need to be able to use keys as strings in the format

-----BEGIN PUBLIC KEY-----
<Base64 Bob>
-----END PUBLIC KEY-----

so far, I have

 private def newJWT(..., private: String, public: String) = Try {
  val privateKey: RSAPrivateKey = ???
  val publicKey: RSAPublicKey = ???


  val algorithm: Algorithm = Algorithm.RSA256(publicKey, privateKey)
  val token: String = JWT.create().
    // ...
    .sign(algorithm)
  // ...
  token
}

How can I convert my string encoded keys into the required RSAPrivateKey interfaced types in the simplest way?