▎ 摘　　要

NOVELTY - Cellobiose dehydrogenase, is new, where the nucleotide sequence encoding the cellobiose dehydrogenase is selected from nucleotide sequence of (SEQ ID NO: 2) with 80 % identity, where sequence is not defined, which is capable of expressing the cellobiose dehydrogenase in the Pichia pastoris. USE - Cellobiose dehydrogenase for use in lactose detection or preparation of lactose biosensor (claimed). ADVANTAGE - The cellobiose dehydrogenase effectively promotes rapid development of the lactose biosensor, and has good actual application value. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for: (1) a recombinant expression vector, which comprises the nucleotide for encoding the cellobiose dehydrogenase; (2) a host cell, which comprises the recombinant vector or the host cell capable of expressing the cellobiose dehydrogenase; (3) a lactose biosensor, which comprises the cellobiose dehydrogenase; (4) a method for electrochemically measuring concentration or presence of lactose, which involves: (a) introducing the lactose biosensor and the liquid sample with or suspected of having contact; and (b) measuring the response current intensity of lactose and analyzing the concentration or presence of lactose.