The invention discloses a method for carrying out alkaline pretreatment on
plant fiber raw materials for preparing
ethanol through enzymolysis and
fermentation. According to the method, firstly, green liquid is used for carrying out alkaline treatment on the air dried
plant fiber raw materials; then, under the condition that the substrate w / v concentration being 5 to 15 percent, the
cellulose is adopted for batch type
hydrolysis for 48 to 72 hours; and after the
hydrolysis completion,
hydrolysate is subjected to
solid-liquid separation, the obtained
clear liquid is concentrated to a state that the glucose concentration in the
sugar liquid is 100 to 200g / L,
hexose in the concentrated
sugar liquid is converted into the
ethanol through brewer's
yeast, the
ethanol mash is removed through
distillation, and then, the
pichia stipitis is used for converting
pentose into the ethanol. The method realizes the goals that the mature process and equipment of the paper pulp process are utilized for recovering chemical
medicine and
heat energy, the consumption of chemicals and the loss of
heat energy are reduced, the environment
pollution is reduced, the clean production of the ethanol is realized, the efficient proceeding of the enzymolysis and the
hexose and
pentose fermentation are respectively ensured through the low-substrate-concentration
enzyme hydrolysis and the sequential
fermentation, particularly, through the
pentose fermentation, the
ethanol yield of each
ton of
plant fiber raw materials is improved, and the
raw material cost of the
ton ethanol is reduced.