Production of composite organic acidifier by fermentation of molasses with yogurt microbial consortium

Abstract:

[Background] Developing safe, effective, stable, palatable, and environmentally friendly antibiotic-free feed additives is the top priority of China’s animal husbandry. As a feed additive, acidifier stands out from the alternatives of antibiotics. [Objective] This study aims to produce low-cost lactic acid-based composite organic acidifier by fermenting beet molasses with yogurt microbial consortium. [Methods] Eleven microbial consortiums used for the fermentation of yogurt by farmers and herdsmen in Xinjiang were taken as the starting bacteria and enriched with MRS medium. The microbial consortiums with high acid production were selected for beet molasses fermentation. The fermentation time, fermentation conditions, molasses concentration, nitrogen source, and neutralizer were optimized. [Results] The optimized conditions of producing composite organic acidifier by fermenting molasses with yogurt microbial consortium were non-sterilized medium, molasses concentration of 100 g/L, and static fermentation at 37 ℃ for 48 h. Under the optimal conditions, the microbial consortium B2 produced 34.52 g/L lactic acid and 83.42 g/L total acids. When Na₂CO₃ was added as the neutralizer, B2 produced 73.42 g/L lactic acid and 169.37 g/L total acids. The microbial consortium B5 produced 61.12 g/L lactic acid and 112.50 g/L total acids. When Ca(OH)₂ was added as the neutralizer, B5 produced 74.37 g/L lactic acid and 137.26 g/L total acids. The fermentation broth of microbial consortium B2 mainly inhibited Salmonella, Staphylococcus aureus, and Clostridium perfringens, and that of microbial consortium B5 mainly inhibited Clostridium perfringens,Salmonella enterica, S.aureus, Escherichia coli O517 and E.coli STEC. [Conclusion] The raw beet molasses fermented with microbial consortiums enriched from Xinjiang farmhouse yogurt flora can produce lactic acid-based composite liquid acidifiers at low costs.