Yu Tianyi, Li Pandeng, Shu Tong, Liu Tingting, Fu Chunhua, Yu Longjiang
Department of Biotechnology, Institute of Resource Biology and Biotechnology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China.
Key Laboratory of Molecular Biophysics, Ministry of Education, Huazhong University of Science and Technology, Wuhan 430074, China.
Polymers (Basel). 2024 Dec 22;16(24):3592. doi: 10.3390/polym16243592.
Hemp fibers, recognized for their breathability, specific strength, and ultraviolet resistance, are widely utilized in textile manufacturing and composite materials. Bio-degumming is a promising alternative technology to traditional chemical degumming that can be used to produce hemp fibers due to its eco-friendly nature. However, its lower efficiency has hindered its widespread adoption. The unclear and complex structure of the gums leads to a poor understanding on the enzyme types required for bio-degumming, thereby restricting improvements in its efficiency. In this study, the morphological characteristics, polysaccharide composition, and branched structure of hemp stem, roving fibers, and refined fibers were investigated using scanning electron microscopy and laser scanning confocal microscopy in combination with immunofluorescence techniques, with a view to identify the enzymes necessary for the efficient bio-degumming of hemp. The results revealed that the gums were primarily located in the middle lamella, phloem parenchyma, and certain xylem tissues. These tissues showed chunk-like, fence-like, and plate-like shapes, respectively, and tightly wrapped around the fiber bundles. In these tissues, pectin comprised low-esterified homogalacturonan, along with rhamnogalacturonan carrying galactan and arabinan branches. Xylan exhibited acetyl, arabinose, and glucuronic acid branches, while mannan displayed acetyl and galactose branches. Partial xylan and mannan were masked by pectin, and the branching structures impeded their enzymatic removal. As a consequence, the necessary enzymes and their synergistic effects for effective hemp roving degumming were elucidated. Pectin degradation was facilitated by pectate lyase and rhamnogalacturonan-degrading enzymes. Xylan and mannan were effectively removed by endo-xylanase and endo-mannanase, a process necessitating the synergistic action of branched-chain-degrading enzymes, including the esterase, α-L-arabinofuranosidase, α-galactosidase, and α-glucuronidase. This study provided practical strategies to enhance the efficiency of hemp bio-degumming.
大麻纤维因其透气性、比强度和抗紫外线性能而闻名，广泛应用于纺织制造和复合材料领域。生物脱胶作为一种替代传统化学脱胶的技术，因其环保特性而有望用于生产大麻纤维。然而，其较低的效率阻碍了它的广泛应用。胶质的结构不清晰且复杂，导致人们对生物脱胶所需的酶类型了解不足，从而限制了其效率的提高。在本研究中，利用扫描电子显微镜、激光扫描共聚焦显微镜结合免疫荧光技术，对大麻茎、粗纱纤维和精制纤维的形态特征、多糖组成和分支结构进行了研究，旨在确定高效生物脱胶大麻所需的酶。结果表明，胶质主要位于胞间层、韧皮薄壁组织和某些木质部组织中。这些组织分别呈现块状、栅栏状和板状，并紧密包裹在纤维束周围。在这些组织中，果胶由低酯化的同型半乳糖醛酸组成，以及带有半乳聚糖和阿拉伯聚糖分支的鼠李糖半乳糖醛酸聚糖。木聚糖具有乙酰基、阿拉伯糖和葡萄糖醛酸分支，而甘露聚糖具有乙酰基和半乳糖分支。部分木聚糖和甘露聚糖被果胶掩盖，其分支结构阻碍了酶对它们的去除。因此，阐明了有效脱胶大麻粗纱所需的酶及其协同作用。果胶酸裂解酶和鼠李糖半乳糖醛酸聚糖降解酶促进了果胶的降解。内切木聚糖酶和内切甘露聚糖酶有效地去除了木聚糖和甘露聚糖，这一过程需要包括酯酶、α-L-阿拉伯呋喃糖苷酶、α-半乳糖苷酶和α-葡萄糖醛酸苷酶在内的支链降解酶的协同作用。本研究为提高大麻生物脱胶效率提供了切实可行的策略。
