Synergistic fermentation of cottonseed meal using Lactobacillus mucosae LLK-XR1 and acid protease: Sustainable production of cottonseed peptides and depletion of free gossypol

This study aimed to determine the optimal fermentation process for enhancing the content of small peptides (C SP ) and the degradation efficiency of free gossypol (D FG ), improving nutritional value. The results indicated that after fermentation, the D FG was reduced to 85.63 % (below both safety standards for human consumption (<200 mg/kg) and animal feed requirements (100–500 mg/kg)), and the C SP content was elevated to 46.25 %. The proportion of soluble protein to total protein and the total free AA were increased by 281.25 % and 1015.68 % than that of the raw feedstock, respectively ( P  < 0.05). Furthermore, the enrichment of harmful bacteria in CSM was inhibited by the fermentation process, and the ability to improve in vitro fermentation characteristics of cows and in vitro dry matter and crude protein digestibility of pigs was also demonstrated by fermented CSM. Overall, the synergistic fermentation process of CSM with LLK-XR1 and acid protease enhanced its nutritional value and bioavailability, offering a practical solution for utilizing CSM.