The present application relates to the technical field of
biotechnology, and particularly relates to a
tagatose-6-
phosphate phosphatase mutant and a method for synthesizing
tagatose from scratch. The method provided by the present application is a one-pot method for biosynthesizing D-
tagatose by using
starch or
dextrin as a substrate, adopting a multi-
enzyme cascade reaction system composed of a tagatose-6-
phosphate phosphatase mutant, a
glycogen-debranching
enzyme, an alpha-
glucan phosphorylase, a
phosphoglucomutase, a glucose-6-
phosphate isomerase, a D-tagatose-6-phosphate-3-epimerase and a 4-alpha-
glucan transferase. The method can prepare tagatose from ordinary and inexpensive starting materials (
starch or
dextrin) at a high yield, improves the overall conversion rate of the
system and the final yield of tagatose, provides a new technical approach for realizing low-cost and
green production of tagatose, and has the advantages of high yield, low cost and being more suitable for industrial production.