Enzymatic process for the fractionation of baker's yeast cell wall (Saccharomyces cerevisiae)

Beta-Glucans in Biotechnology: A Holistic Review with a Special Focus on Yeast

Beta-glucans (β-glucans) are polysaccharides with significant biological activity, widely recognized for their immunomodulatory, anti-inflammatory, and metabolic health benefits. Among various sources, yeast-derived β-(1 → 3), (1 → 6)-glucans have gained particular attention due to their potent bioactivity and diverse applications in biotechnology, pharmaceuticals, and functional foods. This review comprehensively examines yeast β-glucans, covering their biosynthesis, extraction, and purification from industrially relevant yeast strains, particularly Saccharomyces cerevisiae. The impact of fermentation parameters on β-glucan yield and structural properties is analyzed, highlighting advancements in optimizing microbial production. Furthermore, we discuss methods for characterizing yeast β-glucans, including analytical and bioassay techniques, and compare their physicochemical properties with those of β-glucans from other sources. Finally, this review explores the therapeutic potential of yeast-derived β-glucans, focusing on their role in immunomodulation and metabolic regulation and their emerging applications in biomedicine, functional foods, and industrial formulations. By synthesizing recent advancements, this work provides insights into the expanding utilization of yeast β-glucans and their potential for future biotechnological developments.

Structural characteristics of Saccharomyces cerevisiae mannoprotein and its immunomodulatory activities on RAW264.7 cells

An enzyme-extracted mannoprotein (SC-MP) from the cell wall of Saccharomyces cerevisiae was investigated for structural characteristics and immunomodulatory effects on RAW264.7. The SC-MP was purified using the diethylaminoethyl (DEAE) cellulose column and gel column to isolate 2 fractions (MP-1 and MP-2), with MP-1 as the dominant fraction (yield, 87.4 %). The results of composition analyses showed that MP-1, which comprises 88.13 % (w/w) sugar and 6.93 % (w/w) protein, had lower protein content than SC-MP (20.89 %, w/w). Monosaccharide analysis showed MP-1 comprises mannose, glucose, and glucosamine in a molar ratio of 97.64:1.46:0.38. The molecule weight of MP-1 was 141 kDa. The MP-1 was further analyzed using GC-MS, NMR to elucidate its structural characteristics, the results showed that the main sugar residue types of MP-1 included T-D-Manp (45.41 mol%), 1,2,6-D-Manp (21.58 mol%), 1,2-D-Manp (19.45 mol%), and 1,6-D-Manp (6.06 mol%), 1,3-D-Manp (3.91 mol%), and a little amount of 1,6-D-Glcp (3.59 mol%). The mannoses polymerized to form mannan and mano-oligosaccharide. Mannan, which has α-1,6-mannan backbone branched with α-1,2-mannan and α-1,3-mannan, connected to protein by N-glycosylation (via asparagine), and mano-oligosaccharide connected to protein by O-glycosylation (via serine or threonine). At 150 μg/mL concentrations, SC-MP and MP-1, which were different in purity, significantly stimulated the secretion of TNF-α and inhibited the secretion of IL-10 of RAW 264.7 cells, and MP-1 showed stronger effects. This study provided a scientific basis for further exploring the applications of yeast mannoprotein.

β-Glucans obtained from fungus for wound healing: A review

The cell surface of fungus contains a large number of β-glucans, which exhibit various biological activities such as immunomodulatory, anti-inflammatory, and antioxidation. Fungal β-glucans with highly branched structure show great potential as wound healing reagents, because they can stimulate the expression of many immune- and inflammatory-related factors beneficial to wound healing. Recently, the wound healing ability of many fungal β-glucans have been investigated in animals and clinical trials. Studies have proved that fungal β-glucans can promote fibroblasts proliferation, collagen deposition, angiogenesis, and macrophage infiltration during the wound healing process. However, the development of fungal β-glucans as wound healing reagents is not systematically reviewed till now. This review discusses the wound healing studies of β-glucans obtained from different fungal species. The structure characteristics, extraction methods, and biological functions of fungal β-glucans with wound healing ability are summarized. Researches about fungal β-glucan-containing biomaterials and structurally modified β-glucans for wound healing are also involved.

An important polysaccharide from fermentum

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Extraction, structure and modification of polysaccharides from fermentum were summarized.

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Structure-activity relationship and application of polysaccharides from fermentum were reviewed.

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It provided a strong basis for the development and application of polysaccharides from fermentum.

Fermentum is a common unicellular fungus with many biological activities attributed to β-polysaccharides. Different in vivo and in vivo experimental studies have long proven that fermentum β-polysaccharides have antioxidant, anti-tumor, and fungal toxin adsorption properties. However, there are many uncertainties regarding the relationship between the structure and biological activity of fermentum β-polysaccharides, and a systematic summary of fermentum β-polysaccharides is still lacking. Herein, we reviewed the research progress about the extraction, structure and modification, structure–activity relationship, activity and application of fermentum β-polysaccharides, compared the extraction methods of fermentum β-polysaccharide, and paid special attention to the structure–activity relationship and application of fermentum β-polysaccharide, which provided a strong basis for the development and application of fermentum β-polysaccharide.

Characterization of Paenibacillus sp. GKG Endo-β-1, 3-Glucanase, a Member of Family 81 Glycoside Hydrolases

Paenibacillus sp. GKG was isolated based on its ability to produce hydrolysis zones on agar plates containing yeast cell wall substrate as the single carbon source. The extracellular enzymes secreted into the culture medium were identified by LC-MS/MS proteomics. Endo-β-1,3-glucanase PsLam81A containing GH81 catalytic and the CBM56 carbohydrate-binding modules was selected for heterologous expression in Escherichia coli. The identity of the recombinant PsLam81A was confirmed by LC-MS/MS proteomics. The PsLam81A showed the highest activity at 60 °C, and the optimal pH range was between 6.5 and 8.0. The analysis of the full-length PsLam81A and truncated PsLam81AΔCBM56 enzymes showed that the CBM56 module improved the hydrolytic activity towards linear β-1,3-glucans-curdlan and pachyman but had no effect on hydrolysis of β-1,3/β1,6-branched glucans-laminarin and yeast β-glucan. The characterization of PsLam81A enzyme broadens current knowledge on the biochemical properties and substrate specificity of family 81 glycoside hydrolases and allows prediction of the necessity of CBM56 module in the process of designing new truncated or chimeric glycosidases.

Yeast β-1,3-glucan production by an outer membrane β-1,6-glucanase: process optimization, structural characterization and immunomodulatory activity

The β-glucan from Saccharomyces cerevisiae is a potent adjuvant that exhibits a broad spectrum of biological activities and health benefits, and different processes have been established to prepare active β-glucan from yeast. However, studies concerning the effect of β-1,6-glucanase enzymolysis on the structure and immunomodulatory activity of yeast β-1,3-glucan are scarce. In this study, we aim to develop a novel enzymatic process for the preparation of immunologically active β-glucan (BYG) from baker's yeast using a β-1,6-glucanase GluM. The β-1,6-glucan in fungal cell wall was specifically hydrolyzed by GluM, and resulted in cell wall decomposition and β-glucan release. Batch production of BYG was realized with 17.8% yield, 85.3% purity and 75.4% recovery rate. Structural characterization indicated that BYG exhibits rod-like structures with natural triplex and nanoparticle-like substructures compared with the commercial Glucan 300. BYG ameliorated inflammation in a DSS-induced mouse model of colitis through inhibiting oxidative stress (NO, MDA and MPO), inflammatory mediators (NLRP3, ASC, caspase-1, iNOS and COX-2), and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α, IFN-γ), increasing the expression levels of tight junction proteins (ZO-1, occludin and claudin-1) and modulating the production of gut microbiota-synthesized SCFAs compared to the control. Our results showed that yeast β-1,3-glucan prepared with β-1,6-glucanase exhibits structural integrity that is responsible for its favorable immunomodulatory activity.

Immune-enhancing effects of polysaccharide extract of by-products of Korean liquor fermented by Saccharomyces cerevisiae

To increase the value of yeast-fermented Korean liquor by-products, we obtained crude polysaccharide (CPS) fractions via ultrasound-assisted extraction and stepwise-gradient ethanol precipitation and investigated their functionality. Nitric oxide production in RAW 264.7 cells was increased following treatment with the CPSs derived from extract. Analysis of the monosaccharide and amino acid composition of the CPS fractions using HPLC revealed that the polysaccharides were mainly composed of glucose (57.2%), mannose (22.6%), and galactose (17.6%), and no amino acids were detected. In addition, a higher concentration of ethanol solvent for fractionation yielded polysaccharides with lower molecular weights (<15 kDa). CPS 3 and 4 fractions increased the production of TNF-α (15 and 17-fold, respectively) and IL-6 (20 and 18-fold, respectively) and iNOS (65 and 35-fold, respectively) expression at concentration 12.5 μg/mL compared with levels in non-treated RAW 264.7 cells. Especially, CPS 4 at 200 and 400 μg/mL significantly increased the proliferation of mouse spleen cells by 126% and 153%, respectively. These results indicated that CPS 4 enhanced the proliferation of mouse spleen cells in vivo, indicating its immune-enhancing effects. Therefore, this research can contribute to the development of eco-friendly extraction techniques and immune-enhancing materials.

Spent Brewer's Yeast as a Source of Insoluble β-Glucans

In the brewing process, the consumption of resources and the amount of waste generated are high and due to a lot of organic compounds in waste-water, the capacity of natural regeneration of the environment is exceeded. Residual yeast, the second by-product of brewing is considered to have an important chemical composition. An approach with nutritional potential refers to the extraction of bioactive compounds from the yeast cell wall, such as β-glucans. Concerning the potential food applications with better textural characteristics, spent brewer’s yeast glucan has high emulsion stability and water-holding capacity fitting best as a fat replacer in different food matrices. Few studies demonstrate the importance and nutritional role of β-glucans from brewer’s yeast, and even less for spent brewer’s yeast, due to additional steps in the extraction process. This review focuses on describing the process of obtaining insoluble β-glucans (particulate) from spent brewer’s yeast and provides an insight into how a by-product from brewing can be converted to potential food applications.

Maillard conjugates from spent brewer's yeast by-product as an innovative encapsulating material

Yeast-based by-products are greatly available, have a rich nutritional composition and functional properties. The spent brewer's yeast (SBY) cells after enzymatic hydrolysis may be a sustainable and low-cost alternative as carrier material for encapsulation processes by spray drying. Our work had as main purpose to characterise the hydrolysed SBY cell debris after the Maillard reaction and to study their potential as a microencapsulation wall material. SBY-based Maillard reaction products (MRPs) were used to encapsulate ascorbic acid (AA) by spray drying. The Maillard Reaction was able to improve the solubility of solids and proteins by 15% and promoted brown color development (230% higher Browning Index). SBY-based MRPs resulted in particles of a high encapsulation yield of AA (101.90 ± 5.5%), a moisture content of about 3.4%, water activity of 0.15, hygroscopicity values ranging from 13.8 to 19.3 g_H2O/100 g and a glass transition temperature around 71 °C. The shape and microstructure of the produced particles were confirmed by scanning electron microscopy (MEV), indicating very similar structure for control and AA encapsulated particles. Fourier Transform Infrared Spectroscopy (FT-IR) results confirmed the presence of yeast cell debris in the surface of particles. Ascorbic acid was successfully encapsulated in Maillard conjugates of hydrolyzsd yeast cell debris of Saccharomyces pastorianus and maltodextrin as confirmed by optical microscopy, differential scanning calorimetry, MEV and FT-IR.

Antioxidant, antiproliferative, and immunostimulatory effects of cell wall α-d-mannan fractions from Kluyveromyces marxianus

This study evaluated the antioxidant, antiproliferative, and immunostimulatory properties of cell wall α-d-mannan fractions from yeast Kluyveromyces marxianus CCT7735. Filter centrifugation was used to obtain four fractions (KMM-1, KMM-2, KMM-3, and KMM-4) with molecular weight ranging from 7.6 to 75.1kDa. KMM-1 and KMM-2 comprised D-mannose with traces of D-glucose, whereas other fractions contained only D-mannose. Total sugar found in samples ranged from 85.9% to 96.1%, while protein and phenolic contents were 1.21% and 0.41%, respectively. Although only KMM-1 was able to scavenge superoxide radicals, all fractions presented total antioxidant capacity as well as reducing power, hydroxyl-radical scavenging, and copper- and iron-chelating activities. No fraction was cytotoxic to HeLa cells. However, all samples inhibited the proliferation of the tumor cell Hep-G2 and presented minor cytotoxicity against normal 3T3 cells. All fractions showed mitogenic activity in macrophages and all, except KMM-4, induced nitric oxide production in macrophages, suggestive of their immunostimulatory effects.

Effect of a polysaccharide-rich hydrolysate from Saccharomyces cerevisiae (LipiGo®) in body weight loss: randomised, double-blind, placebo-controlled clinical trial in overweight and obese adults

BACKGROUND

In the present study we evaluated the weight loss effect of a polysaccharide-rich food supplement, LipiGo®, comprising a specific β-glucan-chitin-chitosan fraction (BGCC) obtained from the chemical hydrolysis of Saccharomyces cerevisiae, resulting as a by-product of the brewing process.

RESULTS

A randomised, double-blind, placebo-controlled clinical trial was performed enrolling 56 overweight and obese subjects (body mass index, BMI, 25-35 kg m^-2 ) who were not following any specific diet, and were given placebo or BGCC (3 g d^-1 ) for 12 weeks. Results were analysed by intention-to-treat (ITT) and per-protocol (PP) methods. Body weight increased in the placebo group compared to baseline (ITT: 1.0 kg, P < 0.001; PP: 1.5 kg, P = 0.003), while it was slightly lowered in the BGCC group (ITT: -0.8 kg, P = 0.210; PP: -1.1 kg, P = 0.182). BGCC, but not the consumption of placebo, also resulted in a reduction of waist circumference and body fat compared to baseline.

CONCLUSIONS

Results suggest that daily supplementation of BGCC may be useful for improving body weight and waist circumference in overweight and obese subjects, without relevant adverse effects. © 2017 Society of Chemical Industry.