Recent Developments and Applications of Microbial Levan, A Versatile Polysaccharide-Based Biopolymer

Abstract

Polysaccharides are essential components with diverse functions in living organisms and find widespread applications in various industries. They serve as food additives, stabilizers, thickeners, and fat substitutes in the food industry, while also contributing to dietary fiber for improved digestion and gut health. Plant-based polysaccharides are utilized in paper, textiles, wound dressings, biodegradable packaging, and tissue regeneration. Polysaccharides play a crucial role in medicine, pharmacy, and cosmetology, as well as in the production of biofuels and biomaterials. Among microbial biopolymers, microbial levan, a fructose polysaccharide, holds significant promise due to its high productivity and chemical diversity. Levan exhibits a wide range of properties, including film-forming ability, biodegradability, non-toxicity, self-aggregation, encapsulation, controlled release capacity, water retention, immunomodulatory and prebiotic activity, antimicrobial and anticancer activity, as well as high biocompatibility. These exceptional properties position levan as an attractive candidate for nature-based materials in food production, modern cosmetology, medicine, and pharmacy. Advancing the understanding of microbial polymers and reducing production costs is crucial to the future development of these fields. By further exploring the potential of microbial biopolymers, particularly levan, we can unlock new opportunities for sustainable materials and innovative applications that benefit various industries and contribute to advancements in healthcare, environmental conservation, and biotechnology.

Influence of pH on Inulin Conversion to 2,3-Butanediol by Bacillus licheniformis 24: A Gene Expression Assay

“…However, the CRE site with sequence TGAAAACGCTT(a)ACA proposed by Marciniak et al [ 39 ] is not located upstream of sacC in the genome of the strain B. licheniformis 24 and ATCC 14580 T ; therefore, this mechanism most likely does not operate in this species. Thus, sacC expression control in B. licheniformis is most probably governed by LevR as an operon activator and by LevE, which is known to control levR activity [ 42 ].…”

“…In general, both hydrolase and transglycosidase activities obey Michaelis–Menten kinetics, but the balance between them is delicate and depends on numerous factors, such as pH [ 46 ]. Levansucrases are widely distributed across bacterial genera, including Bacillus , but reports in B. licheniformis are relatively scarce [ 42 , 47 ]. In B. licheniformis RN-01, a purified 52 kDa protein is able to synthesize levan with different molecular weights at different temperatures [ 48 ].…”

“…Under fermentation conditions of pH 6.25, sacB was 196.72 times overexpressed, while levB remained unaffected, thus suggesting that the non-coding region (76 bp) between the genes probably prevents their common expression control. Regarding inulinase activity, it is known that levansucrase can break β-2,6 linkages, stopping hydrolysis when reaching a β-2,1 linkage [ 37 , 42 ], thus being rather unrelated to the degradation of inulin. The main effect of the overexpression of sacB is the production of EPS at pH values above 5.75, giving high visual viscosity to the culture liquid, increasing at pH 6.25, corresponding to sacB gene overexpression.…”

Levan Production by Suhomyces kilbournensis Using Sugarcane Molasses as a Carbon Source in Submerged Fermentation

“…Microbial levan is typically obtained through fermentation or enzymatic reactions using isolated enzymes, in which sucrose serves as both a principal carbon source and substrate, respectively. The optimal sucrose concentration for achieving maximum synthesis efficiency varies not only among different species but also often among different strains of microorganisms [ 19 , 20 ]. In the literature, there are various reports that indicate the capacity of some microorganisms to produce levan using sucrose as the only carbon source; among these, we can highlight Bacillus subtilis [ 21 , 22 ], Lactobacillus reuteri [ 23 ], and Leuconostoc citreum [ 24 ] and Gram-negative bacteria such as Gluconobacter albidus [ 25 ], Brenneria goodwinii [ 26 ], Erwinia tasmaniensis [ 27 ], and Halomonas smyrnensis [ 28 ].…”

The influence of selected factors on shaping the quality of the strawberry

“…The use of Bacillus subtilis bacteria in the fermentation process offers the possibility of obtaining raw materials with collagen (Hsu & Chiang, 2009) and hyaluronic acid synthesis-stimulating effects (Jia et al 2013). In addition, studies were presented in which this bacterium may exhibit the ability to synthesize biopolymers, the levan (Domżał- Kędzia et al, 2023), and biosurfactants, such as surfactin (Lewińska et al, 2023). Levan has been confirmed for its beneficial cosmetic properties, including antioxidant (Bouallegue et al, 2020) and skin moisturizing (Lewińska at al., 2021).…”