Meta-l-lactic acid fermentation from non-treated kitchen refuse was reconstructed using a combination of isolated bacterial strains under several pH control strategies. The meta-fermentation system was successfully reconstructed using a combination of Weizmannia coagulans MN-07, Caldibacillus thermoamylovorans OM55-6, and Caldibacillus hisashii N-11 strains. Additionally, a simplified constant pH control strategy was employed, which decreased fermentation time and increased production. The optimum pH (6.5) for the reconstructed meta-fermentation was favorable for the respective pure cultures of the three selected strains. The l-lactic acid production performance of the reconstructed meta-fermentation system was as follows: concentration, 24.5 g L−1; optical purity, 100%; productivity, 0.341 g L−1 h−1; yield, 1.06 g g−1. These results indicated that constant pH control was effective in the reconstructed meta-fermentation with the best performance of l-lactic acid production at pH optimal for the selected bacterial growth, while the switching from swing pH control would suppress the activities of unfavorable bacterial species in un-isolated meta-fermentation. Graphical Abstract and Lay Summary: (Figure presented.) The meta-fermentation system was successfully reconstructed using a combination of three strains isolated from the compost. Additionally, a simplified constant pH control strategy was effective in the reconstructed system with decreased fermentation time and increased production of l-lactic acid at the optimum pH (6.5) value, which was favorable for the respective pure cultures of the three selected strains. The reconstructed meta-LA fermentation system proposed in this study increases organic biomass recycling efficiency.
All Science Journal Classification (ASJC) codes
- Applied Microbiology and Biotechnology
- Molecular Medicine