Wang Junting, Xu Mengying, Tremblay Pier-Luc, Zhang Tian
School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China.
School of Chemistry, Chemical Engineering, and Life Science, Wuhan University of Technology, Wuhan 430070, PR China; State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070, PR China; Shaoxing Institute for Advanced Research, Wuhan University of Technology, Shaoxing 312300, PR China; School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, PR China.
Int J Biol Macromol. 2022 Apr 1;203:526-534. doi: 10.1016/j.ijbiomac.2022.01.179. Epub 2022 Feb 2.
The photocatalyst graphitic carbon nitride (g-CN) is known to photostimulate the production of the bioplastic polyhydroxybutyrate (PHB) by Cupriavidus necator. In previous studies, the combination of C. necator and g-CN increased PHB yield from either an organic or inorganic carbon substrate under a light intensity of 4200 lx. Here, different parameters including light intensity, pH, temperature, nitrogen and carbon concentrations, aeration, and inoculum size were explored to maximize PHB production by hybrid photosynthesis from fructose and visible light. A g-CN/C. necator culture grown with a lower light intensity of 2100 lx, an inoculum size of 128.30 × 10 CFU ml, and constant aeration produced 7.16 g l d PHB with a product yield from fructose of 60.94%. Furthermore, the ratio of incident photons harvested by g-CN converted into NADPH+H by C. necator for PHB production was improved to 19.74% after the process optimization. In comparison, the PHB production rate of a non-optimized g-CN/C. necator system exposed to 4200 lx was only 2.94 g l d with a product yield from fructose of 33.29%. These results demonstrate that hybrid photosynthesis productivity can be significantly augmented by decreasing light intensity and adjusting other parameters, which is promising for future bioproduction applications.
已知光催化剂石墨相氮化碳（g-CN）可光刺激食酸丛毛单胞菌生产生物塑料聚羟基丁酸酯（PHB）。在先前的研究中，食酸丛毛单胞菌与g-CN的组合在4200勒克斯的光照强度下提高了有机或无机碳底物的PHB产量。在此，研究了包括光照强度、pH值、温度、氮和碳浓度、通气和接种量在内的不同参数，以通过果糖和可见光的混合光合作用使PHB产量最大化。在2100勒克斯的较低光照强度、128.30×10 CFU/ml的接种量和持续通气条件下培养的g-CN/食酸丛毛单胞菌培养物，以7.16 g l d的速度生产PHB，果糖的产物产率为60.94%。此外，经过工艺优化后，g-CN捕获的入射光子转化为食酸丛毛单胞菌用于生产PHB的NADPH+H的比例提高到了19.74%。相比之下，暴露在4200勒克斯光照下的未优化g-CN/食酸丛毛单胞菌系统的PHB生产率仅为2.94 g l d，果糖的产物产率为33.29%。这些结果表明，通过降低光照强度和调整其他参数，可以显著提高混合光合作用的生产率，这对未来的生物生产应用很有前景。
