The invention discloses a method for producing
docosahexaenoic acid (DHA) through fermenting a
straw hydrolyzate. The method comprises the following steps of (1) pretreating
straw powder by using an
ammonia gas blasting method, so as to obtain pretreated
straw powder; (2) carrying out enzymolysis on the pretreated straw
powder by using
cellulase, beta-galactosidase and
pectinase, so as to obtain the straw hydrolyzate; (3) adding a culture medium into the straw hydrolyzate, then, inoculating Aurantiochytrium to carry out
fermentation culture, so as to obtain Aurantiochytrium
fermentation liquor; (4) extracting the Aurantiochytrium
fermentation liquor by using mixed liquid of
ethanol and n-
hexane, so as to obtain an extract, and
drying the extract, thereby obtaining the DHA. According to the DHA prepared by the method, the yield is stable; in the case of not adding exogenous glucose, by adopting the method, the
dry weight of obtained thalli can reach 58-66g / L, oil and fat account for 40.8-53.3% of the
dry weight of cells, the DHA accounts for 42.1-45.3% of the
dry weight of the oil and fat, and the DHA yield is 10.3-15.4g / L.