Huong Kai-Hee, Azuraini Mat Junoh, Aziz Nursolehah Abdul, Amirul Al-Ashraf Abdullah
Malaysian Institute of Pharmaceuticals and Nutraceuticals, NIBM, 11700 Gelugor, Penang, Malaysia.
School of Biological Sciences, Universiti Sains Malaysia, 11800 Minden, Penang, Malaysia.
J Biosci Bioeng. 2017 Jul;124(1):76-83. doi: 10.1016/j.jbiosc.2017.02.003. Epub 2017 Apr 27.
Poly(3-hydroxybutyrate-co-4-hydroxybutyrate) [(P(3HB-co-4HB)] copolymer receives attention as next generation biomaterial in medical application. However, the exploitation of the copolymer is still constrained since such copolymer has not yet successfully been performed in industrial scale production. In this work, we intended to establish pilot production system of the copolymer retaining the copolymer quality which has recently discovered to have novel characteristic from lab scale fermentation. An increase of agitation speed has significantly improved the copolymer accumulation efficiency by minimizing the utilization of substrates towards cell growth components. This is evidenced by a drastic increase of PHA content from 28 wt% to 63 wt% and PHA concentration from 3.1 g/L to 6.5 g/L but accompanied by the reduction of residual biomass from 8.0 g/L to 3.8 g/L. Besides, fermentations at lower agitation and aeration have resulted in reduced molecular weight and mechanical strength of the copolymer, suggesting the role of sufficient oxygen supply efficiency in improving the properties of the resulting copolymers. The Ka-based scale-up fermentation was performed successfully in maintaining the yield and the quality of the copolymers produced without a drastic fluctuation. This suggests that the scale-up based on the Ka values supported the fermentation system of P(3HB-co-4HB) copolymer production in single-stage using mixed-substrate cultivation strategy.
聚（3-羟基丁酸酯-co-4-羟基丁酸酯）[(P(3HB-co-4HB)]共聚物作为下一代医用生物材料受到关注。然而，由于这种共聚物尚未成功实现工业规模生产，其开发仍受到限制。在这项工作中，我们旨在建立该共聚物的中试生产系统，同时保持其质量，这种共聚物最近在实验室规模发酵中发现具有新特性。提高搅拌速度通过减少底物用于细胞生长成分的利用，显著提高了共聚物的积累效率。这表现为聚羟基脂肪酸酯（PHA）含量从28 wt%急剧增加到63 wt%，PHA浓度从3.1 g/L增加到6.5 g/L，同时残余生物量从8.0 g/L减少到3.8 g/L。此外，在较低搅拌和通气条件下的发酵导致共聚物的分子量和机械强度降低，这表明充足的氧气供应效率在改善所得共聚物性能方面的作用。基于Ka值的放大发酵成功进行，保持了所生产共聚物的产量和质量，且没有剧烈波动。这表明基于Ka值的放大支持了采用混合底物培养策略在单阶段生产P(3HB-co-4HB)共聚物的发酵系统。
