Lee So Jeong, Kim Jiwon, Ahn Jung Ho, Gong Gyeongtaek, Um Youngsoon, Lee Sun-Mi, Kim Kyoung Heon, Ko Ja Kyong
Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea.
Clean Energy Research Center, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology, Seoul 02792, Republic of Korea.
Bioresour Technol. 2025 Feb;418:131996. doi: 10.1016/j.biortech.2024.131996. Epub 2024 Dec 17.
Lignocellulosic biomass is a promising renewable feedstock for biodegradable plastics like polyhydroxyalkanoates (PHAs). Cupriavidus necator, a versatile microbial host that synthesizes poly(3-hydroxybutyrate) (PHB), the most abundant type of PHA, has been studied to expand its carbon source utilization. Since C. necator NCIMB11599 cannot metabolize xylose, we developed xylose-utilizing strains by introducing synthetic xylose metabolic pathways, including the xylose isomerase, Weimberg, and Dahms pathways. Through rational and evolutionary engineering, the RXI22 and RXW62 strains were able to efficiently utilize xylose as the sole carbon source, producing 64.2 wt% (wt%) and 61.4 wt% PHB, respectively. Among the engineered strains, the xylose isomerase-based RXI22 strain demonstrated the most efficient co-fermentation performance, with a PHB content of 75.7 wt% and a yield of 0.32 (g PHB/g glucose and xylose) from mixed sugars. The strains developed in this study represent an enhanced PHA producer, offering a sustainable route for converting lignocellulosic biomass into bioplastics.
木质纤维素生物质是生产聚羟基脂肪酸酯（PHA）等可生物降解塑料的一种很有前景的可再生原料。食酸戴尔福特菌（Cupriavidus necator）是一种能合成聚（3-羟基丁酸酯）（PHB，PHA中最常见的类型）的多功能微生物宿主，人们对其进行了研究以扩大其碳源利用范围。由于食酸戴尔福特菌NCIMB11599不能代谢木糖，我们通过引入包括木糖异构酶、温伯格途径和达姆斯途径在内的合成木糖代谢途径，开发出了能利用木糖的菌株。通过理性工程和进化工程，RXI22和RXW62菌株能够有效地将木糖作为唯一碳源利用，分别产生64.2%（重量）和61.4%（重量）的PHB。在这些工程菌株中，基于木糖异构酶的RXI22菌株表现出最有效的共发酵性能，PHB含量为75.7%（重量），混合糖产生的PHB产率为0.32（克PHB/克葡萄糖和木糖）。本研究中开发的菌株代表了一种强化的PHA生产者，为将木质纤维素生物质转化为生物塑料提供了一条可持续的途径。
