Iron bioaccumulation in mycelium of Pleurotus ostreatus

Pleurotus florida mediated biosynthesis of nanoparticles and biofortification

The mycosynthesis of biogenic NPs using nanotechnology technique is an ecofriendly and economical approach. The extracellular mycelial extract of the Pleurotus florida fungi were used to biosynthesized Zn, Cu and Fe NPs using zinc sulphate, zinc chloride, copper sulphate, copper chloride ferrous sulphate and ferric chloride, precursor salts at 1.0 mM concentration. The color of reaction mixture was changed from (transparent to white, blue to green and yellow to brown) for Zn, Cu and Fe NPs during incubation period of 96 h at 25 ± 2 °C, indicating synthesis of NPs. Spectroscopy and microscopy techniques were used for the characterization of newly synthesized biogenic NPs. Whereas, the ICP-MS analysis revealed that copper chloride precursor salts produced high concentration of Cu biogenic NPs, followed by zinc chloride derived Zn NPs. The fortification with the biogenic NPs of Pleurotus florida mycelium exhibited high accumulation of the trace elements as compared to non-fortified mycelium.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-023-01307-z.

Production of oyster mushroom (Pleurotus ostreatus) on sawdust supplemented with anaerobic digestate

Anaerobic digestion of organic waste results in production of biogas and a nutrient-rich digestate that has an established use as fertilizer in plant production. This study evaluated use of anaerobic digestate based on a high concentration of organic household waste as a fertilizer in sawdust-based production of oyster mushrooms (Pleurotus ostreatus). Inclusion of 0.5 L of anaerobic digestate (AD) per kg sawdust gave similar productivity in terms of biological efficiency (79.5 ± 5.4 %), and protein concentration (24.7 ± 2.4 % of dry weight (dw)) as standard mushroom substrate (78.1 ± 5.3 %, and 21.9 ± 3.0 % of dw, respectively). However, mushroom growth was impaired at the highest concentration of anaerobic digestate tested, 1 L digestate per kg dw sawdust. Comparison of the AD-fertilized substrate with a mushroom substrate with standard components (sawdust, wheat bran, calcium sulfate) and with similar C/N-ratio revealed some differences in elemental composition of the fruiting bodies, with an major increase in sodium concentration for the AD-fertilized substrate compared with the standard substrate (413.3 ± 28.9 and 226.7 ± 30.6 mg kg^-1 dw, respectively). This difference can be explained by high sodium concentration in the anaerobic digestate, most likely due to inclusion of food scraps from households and restaurants in the biodigester feedstock. Screening of both substrates for a total of 133 micropollutants revealed that total sum of micropollutants was significantly higher in the AD-fertilized substrate (258 ± 12 ng/g dw substrate) than in the standard substrate (191 ± 35 ng/g dw substrate). Nitrogen losses during preparation of the AD-fertilized substrate were negligible.

Biofortification of Three Cultivated Mushroom Species with Three Iron Salts—Potential for a New Iron-Rich Superfood

Mushrooms fortified with iron (Fe) can offer a promising alternative to counter the worldwide deficiency problem. However, the factors that may influence the efficiency of fortification have not yet been fully investigated. The aim of this study was to compare the effects of three Fe forms (FeCl₃ 6H₂O, FeSO₄ 7H₂O, or FeHBED) in three concentrations (5, 10, or 50 mM) for three mushroom species (Pleurotus eryngii, P. ostreatus, or Pholiota nameko) on their chemical composition, phenolic compounds, and organic acid production. The most effective metal accumulation of all the investigated species was for the 50 mM addition. FeCl₃ 6H₂O was the most favorable additive for P. eryngii and P. nameko (up to 145 and 185% Fe more than in the control, respectively) and FeHBED for P. ostreatus (up to 108% Fe more than in control). Additionally, P. nameko showed the highest Fe accumulation among studied species (89.2 ± 7.51 mg kg⁻¹ DW). The creation of phenolic acids was generally inhibited by Fe salt supplementation. However, an increasing effect on phenolic acid concentration was observed for P. ostreatus cultivated at 5 mM FeCl₃ 6H₂O and for P. eryngii cultivated at 5 mM FeCl₃ 6H₂O and 5 mM FeSO₄ 7H₂O. In the case of organic acids, a similar situation was observed. For P. ostreatus, FeSO₄ 7H₂O and FeHBED salts increased the formation of the determined organic acids in fruiting bodies. P. eryngii and P. nameko were characterized by a much lower content of organic acids in the systems supplemented with Fe. Based on the obtained results, we recommend starting fortification by preliminarily indicating which form of the element is preferred for the species of interest for supplementation. It also seems that using an additive concentration of 50 mM or higher is most effective.

Iron-enriched mycelia of edible and medicinal basidiomycetes

Iron bioaccumulation in basidiomycetes is an alternative to recover ferrous sulphate from titanium dioxide pigment production and to produce an iron-enriched mycelial biomass. This study aimed to evaluate iron bioaccumulation capacity in vegetative mycelium of edible and medicinal fungi grown in malt extract liquid medium with different ferrous sulphate contents. Five basidiomycetes were grown in malt extract liquid medium with different iron contents from 0.116 to 100 mg L^-1 iron. The iron content of dried mycelial biomass bioaccumulated with iron was determined by flame atomic absorption spectrophotometry. All fungi grew on the iron culture media and the mycelial biomass growth ranged from 3.24 ± 0.65a mg mL^-1 to 12.46 ± 0.29 mg mL^-1. Iron addition to culture media increased the iron content in the mycelial biomass from 4000-13,000-fold compared with control. Pleurotus ostreatus (2181 ± 218 mg kg^-1) presented the greatest iron content in the mycelial biomass, followed by Schizophyllum commune (1769 ± 131 mg kg^-1), Agaricus subrufescens (1272 ± 8.84 mg kg^-1), and Ganoderma lucidum (840 ± 75 mg kg^-1). P. ostreatus, followed by S. commune, and G. lucidum at 90 and 100 mg L^-1 iron in the culture medium are the best choices to produce iron-enriched mycelial biomass. This extensive study of several edible and medicinal basidiomycetes grown in different iron contents was effective in recovering ferrous sulphate byproduct and transferring it to mycelium to produce a new nutraceutical food of iron-enriched mycelial biomass.

Influence of Iron Addition (Alone or with Calcium) to Elements Biofortification and Antioxidants in Pholiota nameko

Mushrooms supplementation with iron (Fe) is usually limited, and therefore it would be beneficial to search for other vital elements able to improve the process. The aim of this study was to verify a possible interaction between Fe and calcium (Ca) to estimate the role of the addition of the latter metal to stimulate Fe accumulation in Pholiota nameko. Additionally, an analysis of phenolic compounds and low molecular weight organic acids (LMWOAs) was performed. The increase of Fe concentration in the substrate caused a significantly higher accumulation of this metal in P. nameko. The addition of Ca (5 or 10 mM) stimulated Fe accumulation, just as Fe concentration in the substrate stimulated Ca accumulation, which pointed to a synergism between these metals. The obtained results show that the presence of Fe in the substrate may also promote K, Mg, Mn, Na, P, and S accumulation. In contrast, the addition of Ca stimulates and/or inhibits their content in fruit bodies. The phenolic and organic acids profile was poor. Only gallic, 4-hydroxybenzoic, sinapic and syringic acids (phenolics), as well as citric and succinic acids (LMWOAs), were quantified in some combinations in P. nameko fruiting bodies.

Iron Or Zinc Bioaccumulated In Mycelial Biomass Of Edible Basidiomycetes

Iron and zinc bioaccumulation in mycelial biomass of different medicinal basidiomycetes was evaluated in order to produce metal-enriched mycelial biomass as an alternative functional food from non-animal sources and based on biotechnology processes. Pleurotus ostreatus strain U2-9, U2-11, U6-8, and U6-9, Pleurotus eryngii strain U8-11, Schizophyllum commune strain U6-7, and Lentinula edodes strain U6-11 and U6-12 were grown in malt extract agar with or without addition of 50 mg/L iron or 7.5 mg/L zinc. The mycelial biomass was separated and iron and zinc concentrations were determined in a flame atomic absorption spectrophotometer. Basidiomycete strains presented different growth rates with the presence of iron and zinc; there was no dependence between the metal bioaccumulation and the fungal growth. The fungi presented greater capacity to bioaccumulate iron than zinc. P. ostreatus (U2-9) has greater iron bioaccumulation (3197.7 mg/kg) while P. ostreatus (U6-8) greater zinc bioaccumulation (440.4 mg/kg) in mycelial biomass. P. ostreatus (U2-9), P. ostreatus (U2-11), and S. commune (U6-7) had the highest metal translocation rates from the culture medium to mycelial biomass. The mycelial biomass enriched with iron or zinc is an alternative to a new functional food from non-animal sources.

Iron biofortification and availability in the mycelial biomass of edible and medicinal basidiomycetes cultivated in sugarcane molasses

Basidiomycetes can bioaccumulate high iron contents, but there are few studies on iron availability from the mycelial biomass in order to support their use as an iron-enriched fungal food. This study aimed to evaluate the in vitro iron bioaccumulation and availability in the mycelial biomass of edible and medicinal basidiomycetes grown in two distinct culture media. Lentinus crinitus, Ganoderma lucidum, Schizophyllum commune, Pleurotus ostreatus, Pleurotus eryngii, Lentinula edodes, and Agaricus subrufescens were grown in liquid culture medium of malt extract or sugarcane molasses to obtain iron-bioaccumulated mycelial biomass. P. ostreatus was the fungus that most bioaccumulated iron, followed by S. commune, and P. eryngii; they also had the highest mycelial biomass growth and iron transfer from the culture medium to the mycelial biomass. Mycelial iron availability is species-specific, regardless of the culture medium and the iron bioaccumulation capacity of the fungus in the mycelial biomass. Mycelial biomass of S. commune, followed by G. lucidum, P. ostreatus, and P. eryngii, associated with molasses culture medium, are the best choice for the production of iron-enriched mycelial biomass.

Analysis of Fungal Composition in Mine-Contaminated Soils in Hechi City

Fungi play an important role in bioremediation of contaminated soil. However, the diversity of fungal populations in four mine-contaminated soils located in Hechi City has remained unexplored. In this study, high-throughput sequencing of ITS was performed to investigate the diversity and abundance of fungal communities in four mine-contaminated soils in Hechi city. Phylogenetic taxonomy showed that the fungal communities included five phyla. Ascomycota and Basidiomycota were the most abundant phyla in four samples. The most abundant fungi included Agaricomycetes, Nectriaceae, Eurotiomycetes, Mortierellaceae, Incertae sedis, Trichocomaceae, Sordariomycetes, and Fusarium. Various fungi with the potential of bioremediation and industrial application were discussed. The results of fungal composition will provide a clue for isolation of new fungi with the potential of bioremediation and industrial application. Furthermore, this study will lay a good foundation for modifying the indigenous fungi by genetic engineering in the future.

Influence of selenium yeast on the growth, selenium uptake and mineral composition of Coriolus versicolor mushroom

The ability of Coriolus versicolor medicinal mushroom to grow and accumulate selenium during submerged cultivation in a selenium-fortified medium is examined in this paper. For selenium supplementation, commercial selenium yeast was used. Control, nonenriched sample and reference cultures cultivated in the medium enriched with commercial yeast Saccharomyces cerevisiae were also prepared. The mushroom demonstrated a high ability to accumulate selenium from the added source (around 970 and 1,300 µg/g of dry mycelium weight for samples enriched with selenium in a concentration of 10 and 20 mg Se/L, respectively). The addition of selenium significantly (p ≤ .05) increased the biomass yield, whereas the addition of nonenriched yeast had no significant (p ≤ .05) impact. Furthermore, regression analysis showed statistically significant (p ≤ .05) and positive correlations between the content of Se and Fe (r = .92), Se and Cu (r = .92), Se and Mn (r = .98), and Se and Sr (r = .96), suggesting that selenium incorporation was followed by incorporation of these elements, and led to mineral enrichment of the obtained mycelium. Methanol extracts prepared from mycelium biomass demonstrated a better inhibitory effect on Gram-positive bacterial strains with minimal inhibitory concentrations between <0.3125 and 40 mg/ml. The obtained results showed that selenium yeast could be used for obtaining a potential novel food supplement: mushroom biomass with high selenium content and enhanced mineral composition.

Lithium bioaccumulation in Lentinus crinitus mycelial biomass as a potential functional food

Lentinus crinitus is an important basidiomycete consumed by ethnic groups from the Amazon, commonly found in decomposing trees with high lignolytic and antioxidant activities. Lithium is a mood stabilizer, antiepileptic, antipsychotic, and antidepressant used in clinical practice. This study aimed to evaluate L. crinitus mycelial biomass bioaccumulated with lithium in liquid cultivation medium. The malt extract medium was added from zero to 100 mg L^-1 lithium from two lithium sources (Li₂CO₃ and LiCl). The maximum mycelial biomass production was 7218.89 mg L^-1 in the culture medium added with 5 mg L^-1 lithium from LiCl. The highest lithium concentration in the mycelial biomass was of 574.72 μg g^-1 produced in the culture medium with 25 mg L^-1 lithium from Li₂CO₃. Pearson's correlation showed that Li₂CO₃ reduces the mycelial biomass and increases lithium bioaccumulation. The maximum translocated lithium from cultivation medium to mycelial biomass was up to 19 or 28% with LiCl or Li₂CO₃, respectively. Therefore, although Li₂CO₃ presents greater inhibition on the mycelial biomass production, it promoted greater lithium bioaccumulation in L. crinitus mycelial biomass and resulted in greater yield of lithium translocation. The equivalent daily dose of lithium for psychiatric treatment, without bioavailability studies, could be reached with 97.4 g lithium-enriched mycelial biomass and, based in the literature, for reduction of violence and criminality rates the amount could be reached with 0.24-0.58 mg. Thus, the development of lithium-enriched mycelial biomass could be an alternative functional food.

Pleiotropic Roles of ChSat4 in Asexual Development, Cell Wall Integrity Maintenance, and Pathogenicity in Colletotrichum higginsianum

Potassium has an important role to play in multiple cellular processes. In Saccharomyces cerevisiae, the serine/threonine (S/T) kinase Sat4/Hal4 is required for potassium accumulation, and thus, regulates the resistance to sodium salts and helps in the stabilization of other plasma membrane transporters. However, the functions of Sat4 in filamentous phytopathogenic fungi are largely unknown. In this study, ChSat4, the yeast Sat4p homolog in Colletotrichum higginsianum, has been identified. Target deletion of ChSAT4 resulted in defects in mycelial growth and sporulation. Intracellular K⁺ accumulation was significantly decreased in the ChSAT4 deletion mutant. Additionally, the ΔChsat4 mutant showed defects in cell wall integrity, hyperoxide stress response, and pathogenicity. Localization pattern analysis indicated ChSat4 was localized in the cytoplasm. Furthermore, ChSat4 showed high functional conservation with the homolog FgSat4 in Fusarium graminearum. Taken together, our data indicated that ChSat4 was important for intracellular K⁺ accumulation and infection morphogenesis in C. higginsianum.

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.

A Macrosphelide as the Unexpected Product of a Pleurotus ostreatus Strain-Mediated Biotransformation of Halolactones Containing the gem-Dimethylcyclohexane Ring. Part 1

The aim of the study was to obtain new compounds during biotransformation of two halocompounds, the δ-bromo and δ-iodo-γ-bicyclolactones 1 and 2. Unexpectedly Pleurotus ostreatus produced together with the hydroxylactone, 2-hydroxy-4,4-dimethyl-9-oxabicyclo[4.3.0]nonane-8-one (3), its own metabolite (3S,9S,15S)-(6E,12E)-3,9,15-trimethyl-4,10,16-trioxacyclohexa-deca-6,12-diene-1,5,8,11,14-pentaone (4). The method presented here, in which this macrosphelide 4 was obtained by biotransformation, has not been previously described in the literature. To the best of our knowledge, this compound has been prepared only by chemical synthesis to date. This is the first report on the possibility of the biosynthesis of this compound by the Pleurotus ostreatus strain. The conditions and factors, like temperature, salts, organic solvents, affecting the production of this macrosphelide by Pleurotus ostreatus strain were examined. The highest yield of macroshphelide production was noticed for halolactones, as well with iodide, bromide, iron and copper (2+) ions as inductors.

Potential Biotechnological Strategies for the Cleanup of Heavy Metals and Metalloids

Global mechanization, urbanization, and various natural processes have led to the increased release of toxic compounds into the biosphere. These hazardous toxic pollutants include a variety of organic and inorganic compounds, which pose a serious threat to the ecosystem. The contamination of soil and water are the major environmental concerns in the present scenario. This leads to a greater need for remediation of contaminated soils and water with suitable approaches and mechanisms. The conventional remediation of contaminated sites commonly involves the physical removal of contaminants, and their disposition. Physical remediation strategies are expensive, non-specific and often make the soil unsuitable for agriculture and other uses by disturbing the microenvironment. Owing to these concerns, there has been increased interest in eco-friendly and sustainable approaches such as bioremediation, phytoremediation and rhizoremediation for the cleanup of contaminated sites. This review lays particular emphasis on biotechnological approaches and strategies for heavy metal and metalloid containment removal from the environment, highlighting the advances and implications of bioremediation and phytoremediation as well as their utilization in cleaning-up toxic pollutants from contaminated environments.