Regulation of lignocellulose degradation in microorganisms.

Microbial strategies for biomass deconstruction involve an incredible repertoire of enzymatic, structural, and regulatory proteins. From carbohydrate active enzymes to cellulosomes, bacteria, yeast, and filamentous fungi adapt their functional machinery to grow from alternative carbon sources such as lignocellulose and survive starvation. In that context, microbes must be able to sense, bind, degrade, and utilize lignin, cellulose, and hemicelluloses. Nature has developed specialized protein modules, RNA structures, and regulatory systems operating at a genomic, transcription, and translation level. This review briefly summarizes the main regulatory pathways involved in lignocellulose microbial degradation, including carbon catabolite repression; anti-sigma factors; regulatory RNA elements such as small RNAs, antisense RNA, RNA-binding proteins, and selective RNA processing and stabilization; and transcriptional regulators and unfolded protein response. Interplay with global regulators controlling pH response and nitrogen utilization is also revised.

Mushroom Production in the Southern Cone of South America: Bioeconomy, Sustainable Development and Its Current Bloom.

A Sustainable Development Goals (SDGs) based analysis is presented here for business development of the production of edible and medicinal mushrooms using agro-wastes in the Southern Cone of South America. This circular economy approach using edible and medicinal mushroom production on lignocellulosic residues is discussed by analysing both its advantages and drawbacks. Among its main benefits, it is notable that mushroom cultivation using lignocellulosic residues promotes innovation aimed at environmental sustainability, facilitating diversification of the labour supply and the transfer of science to the socio-cultural sphere, which also increases the availability of healthy foods. However, there are some bottlenecks in the process, such as the continuous supply chain of substrates for fungal growth, the lack of equipment and infrastructure for the implementation of cultivation systems in extreme habitats, as well as authorization requirements and other limitations related to a non-fungiphilic culture society. Therefore, this chapter tries to provide key tools for establishing sustainable guidelines for the procurement of local healthy food and other products derived from mushroom cultivation using agricultural residues in the region, which might bloom due to an SDGs-based circular economy approach.

Formulation and Evaluation of a Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes), Nutraceutical Hydroalcoholic Suspension.

Ganoderma lucidum is a mushroom used in traditional Chinese medicine for its purported health benefits. Its complex chemical composition and potential synergies between bioactive compounds make it desirable to design a product that retains most of these compounds in a single formulation. In this article we evaluate a novel G. lucidum nutraceutical suspension (GNS) that reunites two fractions, an ethanolic extract and an aqueous extract, in a single oral liquid product. Back-to-back ethanolic and water extracts were mixed and the fraction that precipitates was recovered. The content of soluble solids, total triterpenoids, high molecular weight carbohydrates, and polyphenols was determined. A suspension was formulated by mixing the extracts and adding different concentrations of Carbomer® 940. The viscosity, physical stability, and particle size distribution were evaluated in all formulations. Almost 9% of the total extractives, consisting mostly of triterpenoids and phenolic compounds from the ethanolic extract, are insoluble in the hydroalcoholic mix and precipitate. This fraction can be suspended and kept stable with the aid of Carbomer® 940, a concentration between 0.5% and 1.0% showing adequate viscosity and particle size distribution. This preparation is an advantageous way of uniting the wide benefits of two G. lucidum extracts in a single oral liquid formulation.

Analysis of the Influence of Substrate Formulations on the Bioactive Chemical Profile of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Agaricomycetes) by Conventional and Chemometrics Methods.

Ganoderma lucidum, a mushroom with medicinal properties, can grow on diverse lignocellulosic substrates. Substrate enrichment with additives has been used as a strategy to increase mushroom productivity. In this study, we evaluated the impact of substrate formulation on the bioactive chemical profile of the basidiome. The bioactive chemical profile of basidiomes cultivated on rice agro-residues (RA) or sunflower seed hulls (SSH) enriched with olive oil and/or copper was evaluated using conventional colorimetric methods and FT-MIR spectrometry coupled with chemometrics. The contents of total triterpenoids, ganoderic acids, high-molecular-weight carbohydrates, and phenolic compounds were sensitive to substrate formulation and harvest time. Moreover, cluster analysis and principal component analysis of the mid-IR spectra were able to discriminate between basidiomes cultivated on either RA or SSH substrates, and for SSH substrates between enriched and nonenriched formulas. These results indicate that the bioactive composition of G. lucidum can be influenced by the formulation of the cultivation substrate.

Biorefining via solid-state fermentation of rice and sunflower by-products employing novel monosporic strains from Pleurotus sapidus.

Pleurotus sapidus monokaryotic strains (Mk) were screened as a novel source of mycelia to valorize rice straw (RS), rice husks (RH) and sunflower seed hulls (SSH) into value-added products through solid-state fermentation (SSF). P. sapidus Dk3174 basidiospores were cultured in the presence of Remazol Brillant Blue R for strain selection, revealing the ligninolytic ability of emerging colonies. Further screening demonstrated the intraspecific variability in dye degradation and enzyme production of 63 strains. Growth rate, biomass and enzyme production in plates containing RS, RH or SSH pointed at MkP6 as a suitable strain for pilot-scale SSF. MkP6 presented a similar laccase profile as the parental Dk3174, being greater in pasteurized substrates (300-1200 U/Kg) than in sterilized substrates (30-250 U/Kg). Peroxidase represented 25% of the total ligninolytic activity measured. The SSH fermented biomass with MkP6 obtained good yields of nanocellulose (67%) and the saccharide release for ethanol production increased by 3-4 times.

DNA damaging potential of Ganoderma lucidum extracts.

ETHNOPHARMACOLOGICAL RELEVANCE: Ganoderma lucidum (Lingzhi or Reishi) is a medicinal mushroom historically used in Asian countries to treat a wide variety of diseases and prolong life. In the last years, G. lucidum has been internationally recognized as an effective adjuvant in cancer treatment. Among active components, the most recent research indicates that polysaccharides modulate the immune response favoring the recovery from toxicity of chemo and radiotherapy while triterpenes are cytotoxic to tumoral cells mainly by altering gene expression. Beyond this body of evidence on the efficacy of G. lucidum in cancer treatment, it is not yet understood whether these extracts exert the same mechanisms of action than current antitumoral drugs. AIM OF THE STUDY: In this study, we tested the DNA damaging potential of G. lucidum extracts by the ß-galactosidase biochemical prophage induction assay (BIA) using doxorubicin, a DNA intercalating agent, as a positive control. This assay was traditionally used to screen microbial metabolites towards antitumoral agents. Here, we used this bacterial assay for the first time to assess DNA damage of herbal drugs. RESULTS: After a bioguided assay, only a purified fraction of G. lucidum containing a mixture of C16 and C18:1 fatty acids exerted weak activity which could not be attributed to direct interaction with DNA. At the same concentrations, the induction observed for doxorubicin was clearly contrasting. CONCLUSIONS: The micro BIA assay could be successfully used to demonstrate differences in cellular effects between G. lucidum extracts and doxorubicin. These results showed that G. lucidum extracts display weak DNA damaging potential. Since DNA injury promotes aging and cancer, our results substantiate the traditional use of this mushroom to prolong life.

Optimization of the Yield of Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (Higher Basidiomycetes), Cultivated on a Sunflower Seed Hull Substrate Produced in Argentina: Effect of Olive Oil and Copper.

Sunflower seed hulls were used as the main component of a solid substrate for the cultivation of the lingzhi or reishi medicinal mushroom Ganoderma lucidum. This study evaluated the effects of supplementing the substrate with olive oil and copper (II) on the mushroom production (MP) parameters and fruiting body total triterpenoid content. The addition of 1.5% olive oil increased total MP by 21.7% (dry basis) in 3 flushes. Copper (60 ppm) increased the daily productivity of the first flush (MP per day) by both reducing the time needed to harvest the crop and increasing the MP. However, the MP at the second and third flushes was reduced. When both supplements were combined, the MP at the first flush was 43% higher than with control treatment. No significant change in mushroom total triterpenoid content was observed by the addition of supplements to the substrate. An increase of 145-155% in the mushroom copper content was obtained by the addition of 60 ppm copper to the substrate. It is thus recommended to use substrate formulations containing both olive oil and copper (II) and harvest just the first flush.

Pyrolysis of sunflower seed hulls for obtaining bio-oils.

Bio-oils from pyrolysis of as received sunflower seed hulls (SSH), hulls previously washed with acid (SSHA) and hulls submitted to a mushroom enzymatic attack (BSSH) were analyzed. The concentration of lignin, hemicellulose and cellulose varied with the pre-treatment. The liquid corresponding to SSH presented a relatively high concentration of acetic acid and a high instability to storage. The bio-oil from SSHA showed a high concentration of furfural and an appreciable amount of levoglucosenone. Lignin was degraded upon enzymatic activity, for this reason BSSH led to the highest yield of bio-oil, with relative high concentration of acetic acid and stability to storage.