酸奶菌群发酵糖蜜产复合有机酸化剂的研究

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

摘要:

【背景】开发安全、有效、稳定、适口性好、对环境无危害的无抗饲料添加剂是我国畜牧业的重中之重，酸化剂作为功能性饲料添加剂在众多替抗产品中有较大的优势。【目的】通过酸奶菌群发酵甜菜糖蜜制备低成本乳酸型复合液态酸化剂。【方法】以11种不同的新疆农牧民传统发酵酸奶菌群为出发菌，经MRS培养基富集乳酸菌群，选择产酸量高的菌群进行甜菜糖蜜发酵试验，并对菌群发酵时间、发酵条件、糖蜜浓度、氮源及中和剂进行优化。【结果】在糖蜜浓度为100 g/L、培养基未灭菌且37 ℃静置发酵48 h时，B2菌群发酵乳酸产量为34.52 g/L，总酸为83.42 g/L，加入中和剂Na₂CO₃后其乳酸产量达73.42 g/L，总酸达到169.37 g/L；B5菌群发酵乳酸产量可达61.12 g/L，总酸可达112.50 g/L，加入中和剂Ca(OH)₂后其乳酸产量达74.37 g/L，总酸为137.26 g/L。B2菌群发酵原液对沙门氏菌、金黄色葡萄球菌及产气荚膜杆菌均有较强的抑制作用；B5菌群发酵原液则对产气荚膜杆菌、沙门氏菌、金黄色葡萄球菌、大肠杆菌O157和大肠杆菌STEC均有较强的抑制作用。【结论】富集新疆农家酸奶菌群，生料发酵甜菜糖蜜可低成本生产乳酸型液态酸化剂。

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.