耐高温半乳糖地质杆菌BWTGW1-1液体发酵工艺优化及中试生产

Optimization of Liquid Fermentation Process and Pilot Production of High Temperature-resistant Geobacillus galactosidasius BWTGW1-1

摘要:

半乳糖地质杆菌（Geobacillus galactosidasius）是畜禽养殖废弃物堆肥发酵过程中常见的菌株类群，在好氧堆肥发酵过程中有重要作用。为获得菌株BWTGW1-1液体发酵的最佳条件，并建立其规模化生产工艺，该研究采用单因素和响应面试验对菌株BWTGW1-1液体发酵培养的组成、发酵条件进行了优化。结果表明菌株BWTGW1-1液体发酵最佳的培养基组成和条件为：甘露醇2.50 g/L、酵母膏8 g/L、大豆蛋白胨5 g/L、氯化钠1.50%，培养温度60 ℃、pH值6.00、液体接种量为0.50%，在此条件下菌株BWTGW1-1液体菌剂OD600值可达1.423 7。在此基础上，基于5 t液体发酵罐体系，建立菌株BWTGW1-1规模化液体发酵工艺，并通过2个批次规模化生产进行验证，获得将近5.50 t菌株BWTGW1-1液体菌剂产品，菌剂有效活菌数能达到7.25×108 CFU/mL，喷雾干燥原粉有效活菌数达到1.12×1010 CFU/g，杂菌率极低（<0.01%）。研究表明菌株BWTGW1-1的最优中试生产发酵条件为，甘露醇2.50 g/L、酵母膏8 g/L、大豆蛋白胨5 g/L、NaCl 1.50 wt.%、pH值6.00、温度60 ℃，发酵0~12 h转速150 r/min，12~24 h转速250 r/min，通气量20 m3/h，发酵时长24 h。

Abstract:

Geobacillus galactosidasius is a common bacterial group in the livestock and poultry waste composting fermentation process, and plays an important role in aerobic composting fermentation. To obtain the optimal liquid fermentation conditions for strain BWTGW1-1 and establish its large-scale production process, a single factor and response surface methodology were used to optimize the composition and fermentation conditions of the liquid fermentation of strain BWTGW1-1. The results showed that the optimal medium composition and conditions for liquid fermentation of strain BWTGW1-1 were as follows: mannitol (2.50 g/L), yeast extract (8 g/L), soy peptone (5 g/L), sodium chloride (1.50%), culture temperature of 60 ℃, pH value 6.00, and liquid inoculum (0.50%). Under these conditions, the OD600 nm value of the liquid inoculum of strain BWTGW1-1 reached 1.423 7. On this basis, using a 5 ton liquid fermentation tank system, a largescale liquid fermentation process for strain BWTGW1-1 was established, and validated through two batches of large-scale production. Nearly 5.50 tons of strain BWTGW1-1 liquid microbial product were obtained, with an effective viable bacterial count of 7.25×108 CFU/mL. The effective viable count in the spray-dried raw powder reached 1.12×1010 CFU/g, with a noticeably low impurity rate (<0.01%). Conclusively, the optimal pilot production fermentation conditions for strain BWTGW1-1 were as follows: mannitol 2.50 g/L, yeast extract 8 g/L, soy peptone 5 g/L, NaCl 1.50 wt.%, pH 6.00, temperature 60 ℃, fermentation speed 150 r/min for 0~12 h, 250 r/min for 12~24 h, ventilation rate 20 m3/h, and fermentation time of 24 h.