Work

Continuous Lactic Acid Fermentation of Actual Food Waste Slurry: Effects of Reaction Temperature and Hydraulic Retention Time

Year: 2025

Type: article

Abstract: Food waste (FW) valorization via lactic acid (LA) fermentation is a promising approach, yet most studies rely on surrogate substrates, limiting industrial applicability. This study investigated continuous LA fermentation of actual FW slurry from a Shenzhen treatment plant, focusing on the effects of hydraulic retention time (HRT: 1.33, 2.0, 3.0 days) and temperature (25, 30, 35, 40 °C) under open-culture conditions. Results showed that hydraulic retention time (HRT) and temperature jointly regulated fermentation performance and microbial communities. Short HRT (1.33 days) caused system instability with fluctuating LA concentrations, while extending the HRT to 2 days enhanced stability, achieving LA concentrations exceeding 14,000 mg/L across all temperatures. Further increasing the HRT to 3 days reduced LA yield and acidification rate, accompanied by acetic/propionic acid accumulation, especially at higher temperatures. Temperature affected the system’s hydrolysis rate, with higher temperatures promoting the hydrolysis of cellulose and hemicellulose. Metagenomic analysis revealed that Lactobacillaceae dominated (>90% of bacteria). The phosphoketolase pathway was the most abundant LA-producing route, and temperature and HRT affected carbohydrate-active enzyme profiles. Balancing efficiency and cost, an HRT of 2 days at 30–35 °C is recommended for industrial LA fermentation of actual FW.

Source: Fermentation

DOI: 10.3390/fermentation11120654

Authors: Luxin Yang, Chuyun Zhao, Caiping Sun, Huan Li

Institutions: Tsinghua Shenzhen International Graduate School, Tsinghua University

Language: English

Topic: Biofuel production and bioconversion

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Responsible consumption and production, Zero hunger

Open Access status: gold

Estimated APC paid: $2,534