Pectin, a heteropolysaccharide derived from plant cell walls, is essential in the food, pharmaceutical, and environmental industries. Currently, citrus and apple peels are the primary sources for commercial pectin production. The yield and quality of pectin extracted from various plant sources significantly differ based on the extraction methods employed, which include physical, chemical, and biological processes. The complex structures of pectin, composed of polygalacturonic acid and rhamnogalacturonan, influence its physicochemical properties and, consequently, its functionality. As a common polysaccharide, pectin finds applications across multiple sectors. In the food industry, it acts as a gelling agent and a packaging material; in pharmaceuticals, it is utilized for drug delivery and wound healing. Environmentally, pectin contributes to wastewater treatment by adsorbing pollutants. Current research focuses on alternative sources, sustainable extraction methods, and multifunctional applications of pectin. Ongoing studies aim to enhance extraction technologies and broaden the applications of pectin, thereby supporting sustainable development goals.

β-mannanase has shown compelling biological functions because of its regulatory roles in metabolism, inflammation, and oxidation. This study separated and purified theβ-mannanase fromBacillus subtilisBE-91, which is a powerful hemicellulose-degrading bacterium using a “two-step” method comprising ultrafiltration and gel chromatography. The purifiedβ-mannanase (about 28.2 kDa) showed high specific activity (79, 859.2 IU/mg). The optimum temperature and pH were 65°C and 6.0, respectively. Moreover, the enzyme was highly stable at temperatures up to 70°C and pH 4.5–7.0. Theβ-mannanase activity was significantly enhanced in the presence of Mn²⁺, Cu²⁺, Zn²⁺, Ca²⁺, Mg²⁺, and Al³⁺and strongly inhibited by Ba²⁺and Pb²⁺.KmandVmaxvalues for locust bean gum were 7.14 mg/mL and 107.5 μmol/min/mL versus 1.749 mg/mL and 33.45 µmol/min/mL for Konjac glucomannan, respectively. Therefore,β-mannanase purified by this work shows stability at high temperatures and in weakly acidic or neutral environments. Based on such data, theβ-mannanase will have potential applications as a dietary supplement in treatment of inflammatory processes.

Pectinase plays a crucial role in ramie bio-degumming. A pectate lyase gene ( pel4J4) from the high-efficiency degumming bacteria Dickeya dadantii DCE-01 of bast fibers was cloned and connected to pET28a, and then the recombinant plasmid was successfully transformed into Escherichia coli BL21(DE3). The pectate lyase (Pel4J4) induced was purified by ultrafiltration and Sephadex G-100 gel chromatography. The enzymatic properties of Pel4J4 were studied in detail. pel4J4 (GenBank accession number: KC900167) had a sequence length of 1179 bp, encoding 392 amino acids. The extracellular pectate lyase activity of pET28a- pel-BL was up to 204.4 IU/mL. The optimal temperature and pH of the purified Pel4J4 were 55℃ and 8.5, respectively. The stable temperature and pH of Pel4J4 activity were 45℃ and 8.5–10.0, respectively. The catalytic activity is Ca²⁺ dependent and promoted by 1 mmol/L Zn²⁺, Fe³⁺, Ca²⁺, and NH₄⁺, but seriously inhibited by Cu²⁺ and Pb²⁺. The optimal substrate is citrus pectin with more than 85% esterification. The heat-resistant alkaline Pel4J4 could strongly degrade natural ramie pectin, indicating a promising application prospect in ramie bio-degumming.

Background: Data on the microbial community and functional proteins associated with degumming in kenaf remains scant. Here, we analyzed the microbial communities associated with kenaf (Hibiscus cannabinus) bast fibers during retting to identify potential candidate degumming bacteria. Retting liquids were collected and analyzed at 0 days, 10 days, and 34 days and then evaluated the yield and quality of kenaf fiber at the different retting times. Besides, the microbial communities were characterized using metagenomic and proteomic analysis by LC–MS/MS technology. Results: The data showed that increase in the retting time significantly improves the softness, dispersion, and fiber whiteness of the kenaf fiber. The relative abundance of Acinetobacter increased from 2.88% at the baseline to 6.64% at the 34th retting. On the other hand, some members of Clostridium were reduced from 3% at the baseline to 2% at the 34th retting. Analysis of carbohydrate active enzymes showed constant changes in the utilization of carbohydrates. Besides, benzoquinone reductase, cellobiose dehydrogenase, glucose 1-oxidase, aryl alcohol oxidase and alcohol oxidase were the top five most abundant enzymes in the retting liquids. This present results demonstrated that the expressions of B7GYR8, Q6RYW5 and Q6FFK2 proteins were suppressed in Acinetobacter with the retting time. On the contrary, P05149 was upregulated with the retting time. In Clostridium, P37698, P52040 and P54937 proteins were upregulated with the retting time. Conclusion: In addition, bacteria Acinetobacter and Clostridium might be playing important roles in the kenaf degumming process. Similarly, up-regulation of P37698, P52040 and P54937 proteins is an important manifestation and mediates important roles in the degumming process.

Among industrial fiber crops, jute is ranked second to cotton in terms of yield and planting area worldwide. The traditional water retting and chemical semi-degumming methods restrict the development of the jute industry. Jute fiber can be extracted from jute bast through mechanical rolling (preprocessing), culture of bacteria, soaking fermentation (liquor ratio = 10, inoculum size = 1 %, temperature = 35 °C, and time = 15 h), inactivation, washing, and drying. Pectobacterium sp. DCE-01 secretes key degumming enzymes: pectinase, mannase, and xylanase, which match well the main non-cellulosic components of jute bast. Compared with the traditional water retting degumming, the bio-degumming cycle is shortened from more than 10 days to 15 h. The proposed bio-degumming achieved higher efficiency and lower pollution than water retting and chemical semi-degumming.

To explore high-quality microbial resources with the capability of ramie degumming, we collected soil samples from rotten ramie and straw heaps. After enrichment culture by ramie raw materials, bacterial strains with the potential ramie-degumming function were screened using a pectin-hydrolysis plate. Dominant bacteria were identified by combining colonial morphological characteristics with the molecular biology method, and their ramie-degumming effects were verified through comprehensive biological degumming indices. Results demonstrated that Bacillus aryabhattai, Bacillus thuringiensis, Lysinibacillus fusiformis, and Acidovorax temperans were successfully obtained. The highest pectinase activity, 98.2 U/mg, was found by A. temperans. B. thuringiensis showed the best ramie-degumming effect. The residual gum content, single-fiber linear density, and bundle-breaking strength of the degummed ramie fiber treated with B. thuringiensis were 8.32%, 6.80 dtex, and 7.84 cN/dtex, respectively. The residual gum content of the ramie fiber treated with B. thuringiensis met the textile requirement (<10%), and the values of all other indicators were also satisfactory. Therefore, B. thuringiensis was an excellent strain for ramie degumming, indicating potential industrial applications.