Men Zhiyue, Zhang Yafei, Pang Zhao, Li Tao, Zhang Hening, Zhou Yue, Hao Ning, Song Yajian, Bai Yu
Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, 300308, China.
College of Biological Engineering, Tianjin University of Science & Technology, Tianjin, 300457, China.
Bioresour Bioprocess. 2025 Jun 25;12(1):68. doi: 10.1186/s40643-025-00886-5.
Galactomannan oligosaccharides (GMOS), composed of 2-10 mannose units linked with β-1, 4 glycosidic bond as the main chain and galactose linked with α-1, 6 glycosidic bond as the side chain, are crucial for probiotic food synthesis due to their ability to promote the growth and activity of beneficial intestinal microbiota, enhance the host immune system, and improve nutrient digestion. GMOS is usually obtained by hydrolyzing plants such as locust bean gum and guar gum with mannanase. β-mannanase ManA from Alkaliphilic Bacillus sp. N16-5 can hydrolyze β-1, 4 glycosidic bond of galactomannan. In this study, an immobilization system was employed utilizing polyhydroxyalkanoate (PHA) biopolymers, which naturally have an affinity mainly mediated by hydrophobic interaction for PhaP protein. Fusion protein combining ManA with PhaP from Aeromonas hydrophila, was subsequently immobilized on PHA support to form a multi-enzyme complex, facilitating the hydrolysis of locust bean gum to generate GMOS. This immobilized enzyme enhances enzyme stability and reusability, can be reused up to 32 times while maintaining ~ 80% of its activity, offering substantial cost savings through in-situ enzyme and product separation. Additionally, the different PHA forms were developed to hydrolyze locust bean gum to produce GMOS, such as nano PHA particles, PHA electrospun materials, while these preliminary investigations show promise, further research is needed to optimize their performance and practical application.
低聚半乳甘露聚糖（GMOS）由2-10个通过β-1,4糖苷键连接的甘露糖单元作为主链，以及通过α-1,6糖苷键连接的半乳糖作为侧链组成，由于其能够促进有益肠道微生物群的生长和活性、增强宿主免疫系统并改善营养消化，因此对益生菌食品的合成至关重要。GMOS通常通过用甘露聚糖酶水解刺槐豆胶和瓜尔胶等植物来获得。嗜碱芽孢杆菌N16-5的β-甘露聚糖酶ManA可以水解半乳甘露聚糖的β-1,4糖苷键。在本研究中，采用了一种利用聚羟基脂肪酸酯（PHA）生物聚合物的固定化系统，PHA天然主要通过疏水相互作用与PhaP蛋白具有亲和力。将ManA与嗜水气单胞菌的PhaP结合的融合蛋白随后固定在PHA载体上，形成多酶复合物，促进刺槐豆胶的水解以产生GMOS。这种固定化酶提高了酶的稳定性和可重复使用性，可重复使用多达32次，同时保持约80%的活性，通过原位酶和产物分离节省了大量成本。此外，还开发了不同形式的PHA来水解刺槐豆胶以生产GMOS，如纳米PHA颗粒、PHA静电纺丝材料，虽然这些初步研究显示出了前景，但仍需要进一步研究来优化它们的性能和实际应用。
