2.2.5. Utilization of immobilized enzyme for pyruvate acid production
with LA produced during storage of food waste
The food waste in this study was obtained from the dining room
of the University of Science and Technology Beijing. Corresponding
treatment and LA fermentation for food waste storage were based
on Ref. [14]. The inoculum size for LAB was determined to be 1%
(V/W). During the storage, pH and LA were determined every
12 h. After 48 h of storage, saccharification of food waste was performed
using glucoamylase with the addition of 100 U/g. Saccharification
of fermentation broth was carried out at 45 C for 5 h.
Then, the broth was separated into solid and liquid parts. The
liquid part was used for ethanol fermentation. To utilize the LA residue,
the immobilized enzyme was inoculated with a dosage of
20 g/100 mL, and the reaction was catalyzed at 55 C for 5 h. The
fermentation broth was inoculated with yeast to produce ethanol.
A corresponding fermentation procedure was mentioned in our
previous study [5,6]. One group, which served as control treatment,
underwent ethanol fermentation without lactic oxidase added.