Provided are a recombinant polypeptide having an excellent acyl-CoA compound reducing activity, and a production method of an aliphatic compound using the recombinant polypeptide.

A recombinant polypeptide has (a) an amino acid sequence A having a sequence identity of 60% or higher, 65% or higher, 70% or higher, 75% or higher, 80% or higher, 85% or higher, 88% or higher, 90% or higher, 93% or higher, 95% or higher, 97% or higher, 98% or higher, or 99% or higher with an amino acid sequence set forth in SEQ ID NO: 1; (b) a substitution of at least one amino acid at a position corresponding to a substrate-binding site of a polypeptide having an amino acid sequence set forth in SEQ ID NO: 1 in the amino acid sequence A; and (c) a reducing activity R of converting CoA thioester of an acyl-CoA compound into an aldehyde group, in which the reducing activity R includes (c-1) a reducing activity R1 of converting adipyl-CoA into 5-formylpentanoic acid in one step; and (c-2) a reducing activity R2 of converting succinyl-CoA into succinic semialdehyde.