Extraction of the Bacterial Extracellular Polysaccharide FucoPol by Membrane-Based Methods: Efficiency and Impact on Biopolymer Properties

Challenges and opportunities in bioprocessing of gellan gum: A review

Gellan gum (GG) - the microbial exopolysaccharide is increasingly being adopted into drug development, tissue engineering, and food and pharmaceutical products. In spite of the commercial importance and expanding application horizon of GG, little attention has been directed toward the exploration of novel microbial cultures, development of advanced screening protocols, strain engineering, and robust upstream or downstream processes. This comprehensive review not only attempts to summarize the existing knowledge pool on GG bioprocess but also critically assesses their inherent challenges. The process optimization design augmented with advanced machine learning modeling tools, widely adopted in other microbial bioprocesses, should be extended to GG. The unification of mechanistic insight into data-driven modeling would help to formulate optimal feeding and process control strategies.

Comprehensive review on recent trends and perspectives of natural exo-polysaccharides: Pioneering nano-biotechnological tools

Exopolysaccharides (EPSs), originating from various microbes, and mushrooms, excel in their conventional role in bioremediation to showcase diverse applications emphasizing nanobiotechnology including nano-drug carriers, nano-excipients, medication and/or cell encapsulation, gene delivery, tissue engineering, diagnostics, and associated treatments. Acknowledged for contributions to adsorption, nutrition, and biomedicine, EPSs are emerging as appealing alternatives to traditional polymers, for biodegradability and biocompatibility. This article shifts away from the conventional utility to delve deeply into the expansive landscape of EPS applications, particularly highlighting their integration into cutting-edge nanobiotechnological methods. Exploring EPS synthesis, extraction, composition, and properties, the discussion emphasizes their structural diversity with molecular weight and heteropolymer compositions. Their role as raw materials for value-added products takes center stage, with critical insights into recent applications in nanobiotechnology. The multifaceted potential, biological relevance, and commercial applicability of EPSs in contemporary research and industry align with the nanotechnological advancements coupled with biotechnological nano-cleansing agents are highlighted. EPS-based nanostructures for biological applications have a bright future ahead of them. Providing crucial information for present and future practices, this review sheds light on how eco-friendly EPSs derived from microbial biomass of terrestrial and aquatic environments can be used to better understand contemporary nanobiotechnology for the benefit of society.

Engineering strategies and applications of cyanobacterial exopolysaccharides: A review on past achievements and recent perspectives

Cyanobacteria are ideally suited for developing sustainable biological products but are underdeveloped due to a lack of genetic tools. Exopolysaccharide (EPS) is one of the essential bioproducts with widespread industrial applications. Despite their unique structural characteristics associated with distinct biological and physicochemical aspects, EPS from cyanobacteria has been underexplored. However, it is expected to accelerate in the near future due to the utilization of low-cost cyanobacterial platforms and readily available information on the structural data and specific features of these biopolymers. In recent years, cyanobacterial EPSs have attracted growing scientific attention due to their simple renewability, rheological characteristics, massive production, and potential uses in several biotechnology domains. This review focuses on the most recent research on potential new EPS producers and their distinct compositions responsible for novel biological activities. Additionally, nutritional and process parameters discovered recently for enhancing EPS production and engineering strategies applied currently to control the biosynthetic pathway for enhanced EPS production are critically highlighted. The process intensification of previously developed EPS extraction and purification processes from cyanobacterial biomass is also extensively explained. Furthermore, the newly reported biotechnological applications of cyanobacterial exopolysaccharides are also discussed.

Marine versus Non-Marine Bacterial Exopolysaccharides and Their Skincare Applications

Bacteria are well-known to synthesize high molecular weight polysaccharides excreted in extracellular domain, which constitute their protective microenvironment. Several bacterial exopolysaccharides (EPS) are commercially available for skincare applications in cosmetic products due to their unique structural features, conferring valuable biological and/or textural properties. This review aims to give an overview of bacterial EPS, an important group of macromolecules used in cosmetics as actives and functional ingredients. For this purpose, the main chemical characteristics of EPS are firstly described, followed by the basics of the development of cosmetic ingredients. Then, a focus on EPS production, including upstream and downstream processes, is provided. The diversity of EPS used in the cosmetic industry, and more specifically of marine-derived EPS is highlighted. Marine bacteria isolated from extreme environments are known to produce EPS. However, their production processes are highly challenging due to high or low temperatures; yield must be improved to reach economically viable ingredients. The biological properties of marine-derived EPS are then reviewed, resulting in the highlight of the challenges in this field.

Development of Emulsions Containing L-Ascorbic Acid and α-Tocopherol Based on the Polysaccharide FucoPol: Stability Evaluation and Rheological and Texture Assessment

The main function of vitamin C, as an antioxidant, is to combat free radicals and prevent premature aging, smoothing wrinkles and expression lines. In addition, it acts directly on depigmentation and prevention of blemishes on the skin. In this study, natural oils (30 wt.%) and α-tocopherol (2.5 wt.%) containing oil-in-water (O/W) emulsions stabilized with the bacterial fucose-rich polysaccharide FucoPol were formulated, adding L-ascorbic acid as an antioxidant. The optimized formulations were obtained with 8.0 wt.% L-ascorbic acid for the Olea europaea oil formulation (C1) with a ƞ value of 2.71 Pa.s (measured at shear rate of 2.3 s−1) and E24 = 96% and with 15 wt.% L-ascorbic acid for the Prunus amygdalus dulcis formulation (C2) with a ƞ value of 5.15 Pa.s (at a shear rate of 2.3 s−1) and E24 = 99%. The stability of the FucoPol-based formulations was investigated over 45 days at 4 °C, 20 °C, and 30 °C. The results showed that all formulations maintained the organoleptic characteristics, with pH variations (5.7–6.8 for C1, and 5.5–6.03 for C2) within the regulations for cosmetic products (4 ≤ pH ≤ 7). The accelerated stability tests proved the formulations’ stability at 4 °C with EI = 95% for C1 and EI = 100% for C2. The rheological assessment demonstrated that the formulation presents a shear-thinning and liquid-like behavior. Regarding textural parameters, formulations C1 and C2 displayed an increase in firmness and consistency with similar spreadability during the shelf life. These findings further demonstrate FucoPol’s functional properties, acting as an emulsifier and stabilizer polysaccharide in cosmetic formulations containing L-ascorbic acid.

Formulation of the Polysaccharide FucoPol into Novel Emulsified Creams with Improved Physicochemical Properties

Driven by the customers' growing awareness of environmental issues, the production of topical formulations based on sustainable ingredients is receiving widespread attention from researchers and the industry. Although numerous sustainable ingredients (natural, organic, or green chemistry-derived compounds) have been investigated, there is a lack of comparative studies between conventional ingredients and sustainable alternatives. In this study, olive oil (30 wt.%) and α-tocopherol (2.5 wt.%) containing oil-in-water (O/W) emulsions stabilized with the bacterial fucose-rich polysaccharide FucoPol were formulated envisaging their validation as cosmetic creams. After formula composition design by Response Surface Methodology (RSM), the optimized FucoPol-based emulsion was prepared with 1.5 wt.% FucoPol, 1.5 wt.% cetyl alcohol, and 3.0 wt.% glycerin. The resulting emulsions had an apparent viscosity of 8.72 Pa.s (measured at a shear rate 2.3 s^-1) and droplet size and zeta potential values of 6.12 µm and -97.9 mV, respectively, which are within the values reported for cosmetic emulsified formulations. The optimized formulation displayed the desired criterium of a thin emulsion system, possessing the physicochemical properties and the stability comparable to those of commercially available products used in cosmeceutical applications.

Deacetylation and Desuccinylation of the Fucose-Rich Polysaccharide Fucopol: Impact on Biopolymer Physical and Chemical Properties

FucoPol is an acylated polysaccharide with demonstrated valuable functional properties that include a shear thinning fluid behaviour, a film-forming capacity, and an emulsion forming and stabilizing capacity. In this study, the different conditions (concentration, temperature, and time) for alkaline treatment were investigated to deacylate FucoPol. Complete deacetylation and desuccinylation was achieved with 0.02 M NaOH, at 60 °C for 15 min, with no significant impact on the biopolymer’s sugar composition, pyruvate content, and molecular mass distribution. FucoPol depyruvylation by acid hydrolysis was attempted, but it resulted in a very low polymer recovery. The effect of the ionic strength, pH, and temperature on the deacetylated/desuccinylated polysaccharide, d-FucoPol, was evaluated, as well as its emulsion and film-forming capacity. d-FucoPol aqueous solutions maintained the shear thinning behaviour characteristic of FucoPol, but the apparent viscosity decreased significantly. Moreover, contrary to FucoPol, whose solutions were not affected by the media’s ionic strength, the d-FucoPol solutions had a significantly higher apparent viscosity for a higher ionic strength. On the other hand, the d-FucoPol solutions were not affected by the pH in the range of 3.6–11.5, while FucoPol had a decreased viscosity for acidic pH values and for a pH above 10.5. Although d-FucoPol displayed an emulsification activity for olive oil similar to that of FucoPol (98 ± 0%) for an oil-to-water ratio of 2:3, the emulsions were less viscous. The d-FucoPol films were flexible, with a higher Young′s modulus (798 ± 152 MPa), a stress at the break (22.5 ± 2.5 MPa), and an elongation at the break (9.3 ± 0.7%) than FucoPol (458 ± 32 MPa, 15.5 ± 0.3 MPa and 8.1 ± 1.0%, respectively). Given these findings, d-FucoPol arises as a promising novel biopolymer, with distinctive properties that may render it useful for utilization as a suspending or emulsifier agent, and as a barrier in coatings and packaging films.

Advances in fermentative production, purification, characterization and applications of gellan gum

Multiple microbial exopolysaccharides have been reported in recent decade with their structural and functional features. Gellan gum (GG) is among these emerging biopolymers with versatile properties. Low production yield, high downstream cost, and abundant market demand have made GG a high cost material. Hence, an understanding on the various possibilities to develop cost-effective gellan gum bioprocess is desirable. This review focuses on details of upstream and downstream process of GG from an industrial perspective. It emphasizes on GG producing Sphingomonas spp., updates on biosynthesis, strain and media engineering, kinetic modeling, bioreactor design and scale-up considerations. Details of the downstream operations with possible modifications to make it cost-effective and environmentally sustainable have been discussed. The updated regulatory criteria for GG as a food ingredient and analytical tools required to validate the same have been briefly discussed. Derivatives of GG and their applications in various industrial segments have also been highlighted.

Development of Olive Oil and α-Tocopherol Containing Emulsions Stabilized by FucoPol: Rheological and Textural Analyses

Biobased raw materials like natural polysaccharides are increasingly sought by the cosmetic industry for their valuable properties. Such biodegradable and usually non-cytotoxic biopolymers are commonly used in skin-care products as rheological modifiers, bioemulsifiers and/or bioactive ingredients. FucoPol is a natural polysaccharide with reported biocompatibility, emulsion-forming and stabilizing capacity, shear-thinning behavior and bioactivity (e.g., antioxidant capacity, wound healing ability) that potentiate its utilization in skin-care products. In this study, olive oil and α-tocopherol containing emulsions were stabilized with FucoPol. Although the presence of α-tocopherol negatively impacted the emulsions’ stability, it increased their emulsification index (EI). Moreover, FucoPol outperformed the commercial emulsifier Sepigel^® 305, under the tested conditions, with higher EI and higher stability under storage for 30 days. The formulation of FucoPol-based emulsions with olive oil and α-tocopherol was studied by Response Surface Methodology (RSM) that allowed the definition of the ingredients’ content to attain high emulsification. The RSM model established that α-tocopherol concentration had no significant impact on the EI within the tested ranges, with optimal emulsification for FucoPol concentration in the range 0.7–1.2 wt.% and olive oil contents of 20–30 wt.%. Formulations with 25 wt.% olive oil and either 0.5 or 2.0 wt.% α-tocopherol were emulsified with 1.0 wt.% or 0.7 wt.% FucoPol, respectively, resulting in oil-in-water (O/W) emulsions. The emulsions had similar shear-thinning behavior, but the formulation with higher FucoPol content displayed higher apparent viscosity, higher consistency, as well as higher firmness, adhesiveness and cohesiveness, but lower spreadability. These findings show FucoPol’s high performance as an emulsifier for olive oil/α-tocopherol, which are supported by an effective impact on the physicochemical and structural characteristics of the emulsions. Hence, this natural polysaccharide is a potential alternative to other emulsifiers.

Characterization of the Thermostable Biosurfactant Produced by Burkholderia thailandensis DSM 13276

Biosurfactants synthesized by microorganisms represent safe and sustainable alternatives to the use of synthetic surfactants, due to their lower toxicity, better biodegradability and biocompatibility, and their production from low-cost feedstocks. In line with this, the present study describes the physical, chemical, and functional characterization of the biopolymer secreted by the bacterium Burkholderia thailandensis DSM 13276, envisaging its validation as a biosurfactant. The biopolymer was found to be a glycolipopeptide with carbohydrate and protein contents of 33.1 ± 6.4% and 23.0 ± 3.2%, respectively. Galactose, glucose, rhamnose, mannose, and glucuronic acid were detected in the carbohydrate moiety at a relative molar ratio of 4:3:2:2:1. It is a high-molecular-weight biopolymer (1.0 × 107 Da) with low polydispersity (1.66), and forms aqueous solutions with shear-thinning behavior, which remained after autoclaving. The biopolymer has demonstrated a good emulsion-stabilizing capacity towards different hydrophobic compounds, namely, benzene, almond oil, and sunflower oil. The emulsions prepared with the biosurfactant, as well as with its autoclaved solution, displayed high emulsification activity (>90% and ~50%, respectively). Moreover, the almond and sunflower oil emulsions stabilized with the biosurfactant were stable for up to 4 weeks, which further supports the potential of this novel biopolymer for utilization as a natural bioemulsifier.