The invention discloses an
alginate lyase (Alg509) derived from marine
bacteria and a
gene thereof, and also disclosed a method for
recombinant expression and preparation of the
alginate lyase. According to the method, the alg509
gene is cloned into an E. coli
expression vector, and the vector is transformed into an E. coli host strain to obtain a recombinant
engineering strain which can heterologously express the
enzyme. The
alginate lyase Alg509 disclosed in the invention has high
enzyme activity, the
specific enzyme activity can reach up to 48000 U / mg and above, the optimum reaction pH is 10, the optimum
reaction temperature is 55 DEG C, and the
enzyme activity has no dependence on various
metal ions. The enzyme is active to
sodium alginate, poly-
guluronic acid (polyG) and ploymannuronic acid (polyM), and can completely degrade
sodium alginate to produce alginate oligomers such as alginate
disaccharide, alginate
trisaccharide, alginate tetrasccharide, etc. The enzyme exhibits strongbasophilia, has certain tolerance to high pH, has certain potential of industrial applications, and can be widely applied in the fields of
agriculture, food,
feed additive,
medicine and the like.