Method for biologically fermenting food waste

The invention relates to a method for biologically fermenting food waste. The method for biologically fermenting the food waste is characterized by comprising steps of firstly, draining the food waste, then smashing the food waste to obtain particles with the volumes smaller than 1.5cm , inoculating aspergillus niger spore suspension with the concentration of 10 -10 spores/mL on the particles, then fermenting the particles in solid states under the condition of temperatures of 32 DEG C for 5 days, stirring the particles once at intervals of 12h and preparing saccharifying enzyme leaven; secondly, smashing solid materials in the fresh food waste to obtain particles with the particle sizes smaller than 0.1cm, respectively adding tap water, the saccharifying enzyme leaven and lactobacillus fermentation lactic acid into the particles and then fermenting the particles under the condition of temperatures of 45 DEG C for 25h; thirdly, separating solid from liquid, and then purifying lactic acid in fermentation liquid by the aid of an electrodialysis process to obtain the lactic acid. The mass of the aspergillus niger spore suspension is 8% of that of the drained food waste. The mass of the tap water is equal to that of the fresh food waste, the mass of the saccharifying enzyme leaven added into the particles is 2.5% of that of the fresh food waste, and the mass of the lactobacillus fermentation lactic acid is 7%-8% of the total mass of the fermentation liquid after the water is added into the food waste. Aspergillus niger is aspergillus niger UV448; each lactobacillus is a lactobacillus TD175; the water content of the fresh food waste in the second step is 75%-85%.