A perspective on the use of Pleurotus for the development of convenient fungi-made oral subunit vaccines

Technological, Biochemical and Microbiological Evaluation of Dehydrated Pleurotus ostreatus Powder for Nutraceutical Applications

Abstract:

Background: Mushroom-based products can serve as superior nutraceuticals in both preventing and alleviati human diseases. Dehydrated powder of Pleurotus ostreatus grown in Cuba has a rich nutritional composition and a large number of therapeutic properties. However, technological parameters (e.g. rheological), as well as biochemical and microbiological quality control standards for its use as a raw material in the manufacture of solid dosage forms with nutraceutical and biopharmaceutical applications have not been established yet.

Objective:

The study aims to determine the technological, biochemical and microbiological quality parameters of dehydrated Pleurotus ostreatus powder.

Method:

Rheological ngproperties (Carr´s index, Hausner´s ratio, angle of repose and flow rate) were determined in seven batches of mushroom powder. Biochemical and microbiological analyses were performed using standard methods. Other physicochemical properties (mean particle size, pH and moisture) were also determined.

Results:

Technical parameters showed a mean particle size of 224.08±7.96 µm, Carr´s compressibility index (23.08-26.58%), Hausner´s ratio (1.30-1.36), angle of repose (36.6-41.90°) and flow rate (3.69-6.93 g cm-2 s-1), typical of materials with poor flowability. Biochemical analyses indicated significant nutraceutical composition: protein (25.0-30.4%), carbohydrate (45-60%), ash (6.1-9.8%), fiber (5-9%), -D-Glucans (1.47-1.61%), iron (21-50 mg/100 g), zinc (3.8-8.0 mg/100 g), and polyphenols (123-160 mg/100 g). Moisture content was ≤3.50% and microbiological analyses were in agreement with ISO standards.

Conclusion:

Dehydrated P. ostreatus powder exhibits good nutraceutical composition and microbiological quality. Technological parameters evidenced poor flow properties, suggesting the need to include excipients to improve the rheological properties for applications as an active ingredient in solid dosage forms for health benefits.

Nutraceutical potential of mushroom bioactive metabolites and their food functionality

Numerous mushroom bioactive metabolites, including polysaccharides, eritadenine, lignin, chitosan, mevinolin, and astrakurkurone have been studied in life-threatening conditions and diseases such as diabetes, cardiovascular, hypertension, cancer, DNA damage, hypercholesterolemia, and obesity attempting to identify natural therapies. These bioactive metabolites have shown potential as antiviral and immune system strengthener natural agents through diverse cellular and physiological pathways modulation with no toxicity evidence, widely available, and inexpensive. In light of the emerging literature, this paper compiles the most recent information describing the molecular mechanisms that underlie the nutraceutical potentials of these mushroom metabolites suggesting their effectiveness if combined with existing drug therapies while discussing the food functionality of mushrooms. The findings raise hope that these mushroom bioactive metabolites may be utilized as natural therapies considering their therapeutic potential while anticipating further research designing clinical trials and developing new drug therapies while encouraging their consumption as a natural adjuvant in preventing and controlling life-threatening conditions and diseases. PRACTICAL APPLICATIONS: Diabetes, cardiovascular, hypertension, cancer, DNA damage, hypercholesterolemia, and obesity are among the world's largest life-threatening conditions and diseases. Several mushroom bioactive compounds, including polysaccharides, eritadenine, lignin, chitosan, mevinolin, and astrakurkurone have been found potential in tackling these diseases through diverse cellular and physiological pathways modulation with no toxicity evidence, suggesting their use as nutraceutical foods in preventing and controlling these life-threatening conditions and diseases.

Biological efficiency and nutritional value of Pleurotus ostreatus cultivated in agroindustrial wastes of palm oil fruits and cocoa almonds

ABSTRACT The cocoa and palm oil agro-industries active in the state of Bahia, Brazil, generate high quantities of lignocellulosic wastes that could be recycled through their use in the formulation of substrates to cultivate edible mushrooms. Pleurotus ostreatus, also known as oyster mushroom, is the second most cultivated mushroom in the world due to its highly appreciated gastronomic, nutritional, and medicinal characteristics. This work evaluated the vertical mycelium growth, biological efficiency, mushroom yield, and nutritional composition of P. ostreatus produced in substrates formulated with a combination of palm oil fruit mesocarp (POFM) and cocoa almond peels (CAP) processing wastes. The substrates were formulated with the following POFM/CAP proportions (%/%): S1 – 86.4/9.6; S2 – 76.8/19.2; S3 – 67.2/28.8; S4 – 57.6/38.4, and S5 – 48.0/48.0. Substrates also received 3% powdered charcoal and 1% calcium carbonate. Substrates S1, S2, S3, and S4 were superior for vertical mycelium growth. S2 promoted the best biological efficiency (148.8%) and yield (560.5g·kg-1).The mushrooms produced in all substrates presented good nutritional values, although mushrooms produced using the S2 presented the highest crude protein content. Overall, S1 is the recommended substrate as it results in higher yields of nutrient rich mushrooms. Production of P. ostreatus in substrates composed of POFM and CAP represents a good alternative for recycling these wastes with potential economic and ecological benefits to regions where palm oil and cocoa are grown.

Polysaccharides of mushroom Pleurotus spp.: New extraction techniques, biological activities and development of new technologies

The biodiversity of mushrooms Pleurotus spp. is impressive due to its complexity and diversity related to the composition of chemical structures such as polysaccharides, glycoproteins and secondary metabolites such as alkaloids, flavonoids and betalains. Recent studies of polysaccharides and their structural elucidation have helped to direct research and development of technologies related to pharmacological action, production of bioactive foods and application of new, more sophisticated extraction tools. The diversity of bioactivities related to these biopolymers, their mechanisms and routes of action are constant focus of researches. The elucidation of bioactivities has helped to formulate new vaccines and targeted drugs. In this context, in terms of polysaccharides and the diversity of mushrooms Pleurotus spp., this review seeks to revisit the genus, making an updated approach on the recent discoveries of polysaccharides, new extraction techniques and bioactivities, emphasising on their mechanisms and routes in order to update the reader on the recent technologies related to these polymers.

Development of a Transgenic Flammulina velutipes Oral Vaccine for Hepatitis B

Orally administered fungal vaccines show promise for the prevention of infectious diseases. Edible mushrooms are deemed appropriate hosts to produce oral vaccines due to their low production cost and low risk of gene contamination. However, their low expression level of antigens has limited the potential development of oral vaccines using mushrooms. The low expression level might result from impurity of the transgenic mycelia since dikaryotic mycelia are commonly used as transformation materials. In this study, stable transgenic hepatitis B virus surface antigen (HBsAg) in Flammulina velutipes transformants was obtained by Agrobacterium-mediated transformation, followed by fruiting and basidiospore mating. The formation of HBsAg was detected by western blot analysis. The expression levels of HBsAg in transgenic F. velutipes fruiting bodies were (129.3±15.1), (110.9±1.7) and (161.1±8.5) ng/g total soluble protein. However, the values may be underestimated due to incomplete protein extraction. Two of the four pigs in the experimental group produced positive anti-HBsAg-specific IgG after being fed the HBsAg transgenic F. velutipes fruiting bodies for 20 weeks, while no anti-HBsAg antibody was detected in the control group. One of the positive pigs had HBsAg titres of 5.36 and 14.9 mIU/mL in weeks 10 and 14, respectively, but expression faded thereafter. The other positive pig displayed HBsAg titres of 9.75, 17.86 and 39.87 mIU/mL in weeks 14, 18 and 20, respectively. The successful immunogenicity in pigs fed transgenic F. velutipes fruiting bodies demonstrated the potential of using the fungus as an oral vaccine.

Mechanisms of Cd and Cr removal and tolerance by macrofungus Pleurotus ostreatus HAU-2

Fungi bioaccumulation is a novel and highly promising approach to remediate polluted soil. The present study revealed a high ability to tolerate Cd and Cr in the fungus Pleurotus ostreatus HAU-2. However, high concentrations of Cd and Cr can suppress fungal growth and result in a variation of hypha micromorphology. Batch experiments were performed to investigate Cd and Cr stress effects on the amount of active oxygen in fungi, activity of antioxidant enzyme, as well as the removal efficiency of Cd and Cr. The results revealed that Cd and Cr caused increasing active oxygen and malonaldehyde (MDA) concentrations. Antioxidant enzymes play a central role in removing active oxygen, while glutathione (GSH) aids the Cd detoxification within cells. In fluid culture, fungal removal rates of Cd and Cr ranged from 44.85% to 80.36% and 14.49% to 45.55%, respectively. Intracellular accumulation and extracellular adsorption were the major removal approaches. Bag cultivation testing indicated that the fungus absorbed Cd and Cr contained within soil. In particular, the accumulation ability of Cd (15.6mgkg^-1) was higher compared to that of Cr (8.9mgkg^-1). These results successfully establish P. ostreatus HAU-2 as promising candidate for the remediation of heavy-metal polluted soils.

Factors affecting mushroom Pleurotus spp

Pleurotus genus is one of most extensively studied white-rot fungi due to its exceptional ligninolytic properties. It is an edible mushroom and it also has several biological effects, as it contains important bioactive molecules. In basidiomycete fungi, lignocellulolytic enzymes are affected by many typical fermentation factors, such as medium composition, ratio of carbon to nitrogen, pH, temperature, air composition, etc. The survival and multiplication of mushrooms is related to a number of factors, which may act separately or have interactive effects among them. Out that understanding challenges in handling Pleurotus species mushroom requires a fundamental understanding of their physical, chemical, biological and enzymatic properties. This review presents a practical checklist of available intrinsic and extrinsic factors, providing useful synthetic information that may help different users. An in-depth understanding of the technical features is needed for an appropriate and efficient production of Pleurotus spp.

The Last Ten Years of Advancements in Plant-Derived Recombinant Vaccines against Hepatitis B

Disease prevention through vaccination is considered to be the greatest contribution to public health over the past century. Every year more than 100 million children are vaccinated with the standard World Health Organization (WHO)-recommended vaccines including hepatitis B (HepB). HepB is the most serious type of liver infection caused by the hepatitis B virus (HBV), however, it can be prevented by currently available recombinant vaccine, which has an excellent record of safety and effectiveness. To date, recombinant vaccines are produced in many systems of bacteria, yeast, insect, and mammalian and plant cells. Among these platforms, the use of plant cells has received considerable attention in terms of intrinsic safety, scalability, and appropriate modification of target proteins. Research groups worldwide have attempted to develop more efficacious plant-derived vaccines for over 30 diseases, most frequently HepB and influenza. More inspiring, approximately 12 plant-made antigens have already been tested in clinical trials, with successful outcomes. In this study, the latest information from the last 10 years on plant-derived antigens, especially hepatitis B surface antigen, approaches are reviewed and breakthroughs regarding the weak points are also discussed.