Davis Reeta, Duane Gearoid, Kenny Shane T, Cerrone Federico, Guzik Maciej W, Babu Ramesh P, Casey Eoin, O'Connor Kevin E
School of Biomolecular and Biomedical Science, University College Dublin, Dublin 4, Ireland; Technology Centre for Biorefining and Bioenergy, National University of Ireland, Galway, Ireland.
Biotechnol Bioeng. 2015 Apr;112(4):725-33. doi: 10.1002/bit.25474. Epub 2014 Nov 19.
High Cell Density (HCD) cultivation of bacteria is essential for the majority of industrial processes to achieve high volumetric productivity (g L(-1) h(-1) ) of a bioproduct of interest. This study developed a fed batch bioprocess using glucose as sole carbon and energy source for the HCD of the well described biocatalyst Pseudomonas putida KT2440 without the supply of oxygen enriched air. Growth kinetics data from batch fermentations were used for building a bioprocess model and designing feeding strategies. An exponential followed by linearly increasing feeding strategy of glucose was found to be effective in maintaining biomass productivity while also delaying the onset of dissolved oxygen (supplied via compressed air) limitation. A final cell dry weight (CDW) of 102 g L(-1) was achieved in 33 h with a biomass productivity of 3.1 g L(-1) h(-1) which are the highest ever reported values for P. putida strains using glucose without the supply of pure oxygen or oxygen enriched air. The usefulness of the biomass as a biocatalyst was demonstrated through the production of the biodegradable polymer polyhydroxyalkanoate (PHA). When nonanoic acid (NA) was supplied to the glucose grown cells of P. putida KT2440, it accumulated 32% of CDW as PHA in 11 h (2.85 g L(-1) h(-1) ) resulting in a total of 0.56 kg of PHA in 18 L with a yield of 0.56 g PHA g NA(-1) .
对于大多数工业生产过程而言，细菌的高细胞密度（HCD）培养对于实现目标生物产品的高体积生产力（g L⁻¹ h⁻¹）至关重要。本研究开发了一种补料分批生物工艺，该工艺使用葡萄糖作为唯一的碳源和能源，用于高细胞密度培养已得到充分描述的生物催化剂恶臭假单胞菌KT2440，且无需供应富氧空气。来自分批发酵的生长动力学数据用于构建生物工艺模型并设计补料策略。结果发现，先指数后线性增加的葡萄糖补料策略在维持生物质生产力的同时，还能延迟溶解氧（通过压缩空气供应）限制的出现。在33小时内实现了102 g L⁻¹的最终细胞干重（CDW），生物质生产力为3.1 g L⁻¹ h⁻¹，这是使用葡萄糖且不供应纯氧或富氧空气的恶臭假单胞菌菌株所报道的最高值。通过生产可生物降解聚合物聚羟基脂肪酸酯（PHA）证明了生物质作为生物催化剂的有效性。当向恶臭假单胞菌KT2440的葡萄糖生长细胞供应壬酸（NA）时，它在11小时内积累了占CDW 32%的PHA（2.85 g L⁻¹ h⁻¹），在18升中总共产生了0.56千克PHA，产率为0.56 g PHA g NA⁻¹。
