Biocatalytic Conversion of Carrageenans for the Production of 3,6-Anhydro-D-galactose

Marine algal polysaccharides: Multifunctional bioactive ingredients for cosmetic formulations

Marine algal polysaccharides (MAP) are increasingly recognized as versatile bioactive ingredients in cosmetics due to their wide-ranging therapeutic benefits and eco-friendly sourcing. Sourced from red, brown, and green algae, these polysaccharides deliver numerous advantages for skin health, including antioxidant, anti-inflammatory, anti-aging, hydrating, and regenerative properties. As demand for natural and sustainable products grows, MAP offer a renewable and environmentally responsible alternative to synthetic chemicals. This review examines the chemical structures, extraction methods, biological activities, and cosmetic applications of key MAP, such as carrageenans, alginates, fucoidans, laminaran, ulvan, and sulfated rhamnan. It also discusses emerging research trends, innovative extraction techniques, and the formulation of multifunctional products that combine these polysaccharides with other bioactive compounds. As consumer preferences increasingly lean toward ethical and sustainable choices, MAP are well-positioned to contribute to the development of high-performance cosmetic products that meet both industry standards and consumer expectations.

The discovery of a random endo-acting ι-carrageenase with bifunctional activities against ι-carrageenan and κ-carrageenan

Carrageenans have attracted increasing research interests in recent decades for their various physicochemical and physiological properties. Random endo-acting carrageenases are promising tools for tailoring the molecular weight of carrageenan and preparing a series of carrageenan oligosaccharides. Although the processive ι-carrageenases in the GH82 family have been widely investigated, the random ι-carrageenase has not been reported. Herein, a novel GH82 family protein Cg82Mf, which was identified by AlphaFold2 as lacking a lid structure on the catalytic groove, was cloned and expressed in Escherichia coli. The analysis of hydrolysis pattern proved that Cg82Mf was the first random endo-acting enzyme against ι-carrageenan, and was capable of preparing the hydrolysis products with various degrees of polymerization. Cg82Mf exhibited higher substrate affinity among all characterized ι-carrageenases, reflected by its low Km value (0.18 μM). Remarkably, Cg82Mf could also hydrolyze κ-carrageenan, that is, the subsites of the enzyme could tolerate κ-carrageenan disaccharide units, which demonstrated a novel cleavage specificity. The novel hydrolysis pattern and cleavage specificity shed light on the presence of diversity within the GH82 family, and indicated that Cg82Mf could be facilitated as a potential biocatalyst for the molecule tailoring of carrageenans.

Simultaneous One-Step Preparation of β/κ-Carrapentaose and 3,6-Anhydro-D-galactose by Cascading κ-Carrageenase and an Exo-α-3,6-Anhydro-D-galactosidase

Carrageenan oligosaccharides have shown promising bioavailability and possess a variety of physiological activities, making them highly suitable for use in the food, pharmaceutical, and agricultural industries. The preferred method for producing carrageenan oligosaccharides is using various carrageenolytic enzymes, as it offers mild reaction conditions, high efficiency, and product specificity. However, there is still a lack of specific applications for using these enzymes to prepare odd-numbered carrageenan-oligosaccharides (OCOSs). Our previous research identified a more convenient route for simultaneously preparing OCOSs and 3,6-anhydro-D-galactose (D-AHG) using only two types of carrageenolytic enzymes: κ-carrageenase and exo-α-3,6-anhydro-D-galactosidase (D-ADAGase). In this study, we utilized a CipA-based self-assembly system to cascade κ-carrageenase CaKC16A and D-ADAGase ZuGH129A for one-step preparation of β/κ-carrapentaose, G-(DA-G4S)2, and D-AHG from degrading β/κ-carrageenan. This self-assembled enzyme, namely CipA-CaKC16A-ZuGH129A, can be easily obtained through a simple centrifugation process. The final optimized enzymatic process produced 0.74 g/L G-(DA-G4S)2 and 0.13 g/L D-AHG. This cascade system of different types of carrageenolytic enzymes has the potential to achieve the preparation of various types of carrageenan oligosaccharides.

Systematic review on carrageenolytic enzymes: From metabolic pathways to applications in biotechnology

Carrageenan, the major carbohydrate component of some red algae, is an important renewable bioresource with very large annual outputs. Different types of carrageenolytic enzymes in the carrageenan metabolic pathway are potentially valuable for the production of carrageenan oligosaccharides, biofuel, and other chemicals obtained from carrageenan. However, these enzymes are not well-developed for oligosaccharide or biofuel production. For further application, comprehensive knowledge of carrageenolytic enzymes is essential. Therefore, in this review, we first summarize various carrageenolytic enzymes, including the recently discovered β-carrageenase, carrageenan-specific sulfatase, exo-α-3,6-anhydro-D-galactosidase (D-ADAGase), and exo-β-galactosidase (BGase), and describe their enzymatic characteristics. Subsequently, the carrageenan metabolic pathways are systematically presented and applications of carrageenases and carrageenan oligosaccharides are illustrated with examples. Finally, this paper discusses critical aspects that can aid researchers in constructing cascade catalytic systems and engineered microorganisms to efficiently produce carrageenan oligosaccharides or other value-added chemicals through the degradation of carrageenan. Overall, this paper offers a comprehensive overview of carrageenolytic enzymes, providing valuable insights for further exploration and application of these enzymes.