The invention relates to an isolated polypeptide having NADH dependent HMF reductase activity, wherein said polypeptide shows 80% homology to the amino acid sequence shown in SEQ ID NO:2 and which differs from SEQ ID NO:2 in that at least S117L and Y295 or S110 is substituted, a nucleotide sequence coding for said polypeptide, a vector comprising said polypeptide or nucleotide sequence, host comprising said nucleotide sequence or vector as well as the use of the polypeptide for the reduction of furan or carbonyl compounds in lignocellulosic material or in any furan or carbonyl containing material.