Lactic acid production from co-fermentation of food waste and spent mushroom substance with Aspergillus niger cellulase

Abstract

The feasibility of co-fermentation of food waste and spent mushroom substance for lactic acid with Aspergillus niger cellulase replacing commercial cellulase was explored. In this study, Enterococcus mundtii was used in this study because it could utilize hexose and pentose. When the ratio of food waste and spent mushroom substance was 1:2, lactic acid concentration was 39.22 g/L, 39.28% higher than the weighted average of experimental lactic acid concentrations, indicating that the co-fermentation had positive synergistic effects. Results showed 92.62% of sugars of pretreated spent mushroom substance was released by Aspergillus niger cellulase. Moreover, when Aspergillus niger cellulase was added into the lactic acid fermentation system at 24 h, lactic acid concentration reached 48.72 g/L, which was 22.97% higher than that of the control group with commercial cellulase, because of the disappearance of Veillonella and Saccharomycetales with the Aspergillus niger cellulase addition, thus making more substrates converted into lactic acid.