The responses of organic acid production and microbial community to different carbon source additions during the anaerobic fermentation of Chinese cabbage waste

The effects of glucose, fructose, sucrose and molasses on organic acid levels, protein degradation, nutrient preservation and bacteriome were studied during the anaerobic fermentation of Chinese cabbage waste. The results showed that fructose and molasses additions caused a significant (p < 0.05) increase in lactic acid pro-duction (82.16-89.79 %), acetic acid production (175.41-196.93 %), ammonia nitrogen formation (15.93-37.43 %) and reduction of neutral detergent fiber level (8.17-15.87 %). However, few positive effects of glucose and sucrose additions were found on organic acid production. Furthermore, carbon source additions enriched (p < 0.05) the acid-producing bacteria, such as Lactobacillus paralimentarius and Lactobacillus hei-longjiangensis, upregulated (p < 0.05) the pathways of carbohydrate and lipid metabolisms and reduced (p < 0.05) the abundances of Lactobacillus buchneri and Escherichia coli and bacteria that were mobile elements-contained and stress-tolerant. Collectively, fructose and molasses additions enhanced the recycling of Chinese cabbage waste by anaerobic fermentation, in which the desired products are organic acids.

Automated summary

The study investigated the effects of glucose, fructose, sucrose, and molasses on the anaerobic fermentation of Chinese cabbage waste. Fructose and molasses additions significantly increased lactic acid production, acetic acid production, ammonia nitrogen formation, and reduced neutral detergent fiber level. Glucose and sucrose additions had limited effects on organic acid production. Additionally, carbon source additions enriched acid-producing bacteria, upregulated carbohydrate and lipid metabolism pathways, and reduced the abundances of specific bacteria. Overall, fructose and molasses additions enhanced the recycling of Chinese cabbage waste into organic acids.