机械搅拌发酵产细菌纤维素的中试研究
Mechanical stirring fermentation pilot study of bacterial cellulose
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摘要: 细菌纤维素的中试发酵实验研究是其工业化生产的必经阶段,有着极为重要的研究价值和意义。利用实验室20 L-50 L-100 L机械搅拌发酵罐系统对发酵生产细菌纤维素进行了中试实验,测定了葡糖杆菌在20 L种子罐中的生长曲线,研究了不同培养级数的种子对100 L机械发酵罐的影响,采用转速-溶氧(DO)联动控制法提高发酵中后期的溶氧水平和纤维素产量。结果表明,在种子生长曲线对数期的中后期(3048 h)移种较佳,使用三级种子移种比一级和二级种子移种的发酵周期分别短62 h和14 h,保持移种后发酵罐的菌体浓度在2.0×107CFU/m L以上对缩短发酵过程延滞期有利,转速-DO联动控制可保证发酵中后期DO维持在30%左右,纤维素产量由2.2 g/L提高至2.8 g/L。细菌纤维素的中试实验结果对探索生产工艺、缩短发酵周期、降低生产成本、提高纤维素产量等方面有明显改善,为其工业化生产奠定了基础。Abstract: The pilot fermentation experiment of bacterial cellulose( BC) is a necessary stage for its industrial production.It has a very important value and significance. The pilot fermentation experiment were systematically researched using 20 L- 50 L- 100 L laboratory stirred tank fermentation system. The growth curve of Komagataeibacter nataicola seeds at 20 L fermentor were determined. The effects of different seed culture series on 100 L mechanical fermentation tank were studied. To improve the level of dissolved oxygen,stirring speed-dissolved oxygen( DO) linkage control method were used during fermentation and cellulose production.The results showed that suitable inoculation period was in the middle and late stage of logarithmic phase( 30 ~ 48 h). The fermentation period using grade three seed was 62 h and 14 h shorter than grade one and two,respectively. To shorten the fermentation process delay time,the bacteria concentration in the fermentation tank was more than 2.0× 107 CFU / m L after inoculation with bacteria. Stirring speed- DO linkage control could ensure DO maintained at around 30% and increased BC yield to 2.8 g / L.This research was beneficial with shortening the fermentation cycle,reducing the production cost,improving the yield of cellulose,and laying foundations for the industrial production.The pilot experiment study results of BC had a significant improvement in the production process.