Ganoderic Acid Production Research Articles

Improved ganoderic acids production in Ganoderma lucidum by wood decaying components

Ganoderma lucidum is a legendary Traditional Chinese Medicine (TCM) over a few thousands of years and one kind of its major active components are Ganoderic acids (GAs). GAs are largely produced in the mushroom primordium and fruiting body but much less in mycelium stage. However, little is known on the underlying regulatory mechanism. As a saprophytic fungus, G. lucidum solely obtains nutrients by wood decaying. Wood in general contains sophisticated chemical components with diverse structural units. To explore a strategy that extensively leads to GAs induction in the submerged liquid fermentation, all chemical components that might be possibly from the wood decaying were tested individually as GAs inducers. It was found that GAs production increased 85.96% by 1.5% microcrystalline cellulose (MCC) and 63.90% by 0.5% D-galactose. The transcription level of a few rate-limiting or chemically diverting enzymes responsible for GAs biosynthesis was greatly induced by MCC and D-galactose. The concentration and time-course titration study indicated that these two chemicals might not be utilized as carbon sources but they played a comprehensive role in the secondary metabolites synthesis. Our data indicated that MCC and D-galactose might be further industrialized for higher GAs production in G. lucidum in submerged fermentation.

Enhancement of ganoderic acid production by constitutively expressing Vitreoscilla hemoglobin gene in Ganoderma lucidum

Enhancement of ganoderic acid production by constitutively expressing Vitreoscilla hemoglobin gene in Ganoderma lucidum

Enhancement of ganoderic acid production by constitutively expressing Vitreoscilla hemoglobin gene in Ganoderma lucidum

The Vitreoscilla hemoglobin (VHb) gene was expressed in Ganoderma lucidum to enhance antitumor ganoderic acid (GA) production. The effects of VHb expression on the accumulation of GAs and lanosterol (intermediate) and the transcription of GA biosynthesis genes were also investigated. In VHb-expressing G. lucidum, the maximum concentrations of four individual GAs (GA-S, GA-T, GA-Mk and GA-Me) were 19.1±1.8, 34.6±2.1, 191.5±13.1 and 45.2±2.8μg/100mg dry weight, respectively, which were 1.4-, 2.2, 1.9- and 2.0-fold higher than those obtained in the wild-type strain. Moreover, the maximum lanosterol concentration in the strain expressing VHb was 1.28-fold lower than that in the wild-type strain. The transcription levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase, squalene synthase, and lanosterol synthase genes were up-regulated by 1.6-, 1.5-, and 1.6-fold, respectively, in the strain expressing VHb. This work is beneficial in developing an efficient fermentation process for the hyperproduction of GAs.

Sucrose fed-batch strategy enhanced biomass, polysaccharide, and ganoderic acids production in fermentation of Ganoderma lucidum 5.26.

Ganoderma, as a Chinese traditional medicine, has multiple bioactivities. However, industrial production was limited due to low yield during Ganoderma fermentation. In this work, sucrose was found to greatly enhance intracellular polysaccharide (IPS) content and specific extracellular polysaccharide (EPS) production rate. The mechanism was studied by analyzing the activities of enzymes related to polysaccharide biosynthesis. The results revealed that sucrose regulated the activities of phosphoglucomutase and phosphoglucose isomerase. When glucose and sucrose mixture was used as carbon source, biomass, polysaccharide and ganoderic acids (GAs) production was greatly enhanced. A sucrose fed-batch strategy was developed in 10-L bioreactor, and was scaled up to 300-L bioreactor. The biomass, EPS and IPS production was 25.5, 2.9 and 4.8 g/L, respectively, which was the highest biomass and IPS production in pilot scale. This study provides information for further understanding the regulation mechanism of Ganoderma polysaccharide biosynthesis. It demonstrates that sucrose fed-batch is a useful strategy for enhancing Ganoderma biomass, polysaccharide and GAs production.

Genetic engineering of Ganoderma lucidum for the efficient production of ganoderic acids

Ganoderma lucidum is a well-known traditional medicinal mushroom that produces ganoderic acids with numerous interesting bioactivities. Genetic engineering is an efficient approach to improve ganoderic acid biosynthesis. However, reliable genetic transformation methods and appropriate genetic manipulation strategies remain underdeveloped and thus should be enhanced. We previously established a homologous genetic transformation method for G. lucidum; we also applied the established method to perform the deregulated overexpression of a homologous 3-hydroxy-3-methyl-glutaryl coenzyme A reductase gene in G. lucidum. Engineered strains accumulated more ganoderic acids than wild-type strains. In this report, the genetic transformation systems of G. lucidum are described; current trends are also presented to improve ganoderic acid production through the genetic manipulation of G. lucidum.

Further improvement in ganoderic acid production in static liquid culture of Ganoderma lucidum by integrating nitrogen limitation and calcium ion addition.

To further improve the ganoderic acid (GA) production, a novel integrated strategy by combining nitrogen limitation and calcium ion addition was developed. The effects of the integrated combination on the content of GA-T (one powerful anticancer compound), their intermediates (squalene and lanosterol) and on the transcription levels of GA biosynthetic genes in G. lucidum fermentation were investigated. The maximum GA-T content with the integrated strategy were 1.87 mg/ 100 mg dry cell weight, which was 2.1-4.2 fold higher than that obtained with either calcium ion addition or nitrogen limitation alone, and it is also the highest record as ever reported in submerged fermentation of G. lucidum. The squalene content was increased by 3.9- and 2.2-fold in this case compared with either individual strategy alone. Moreover, the transcription levels of the GA biosynthetic genes encoding 3-hydroxy-3-methyglutaryl coenzyme A reductase and lanosterol synthase were also up-regulated by 3.3-7.5 and 1.3-2.3 fold, respectively.

Induction of ganoderic acid biosynthesis by Mn2+ in static liquid cultivation of Ganoderma lucidum

Metal ions affect cell physiology and metabolism significantly, but the role of Mn(2+) in the secondary metabolism of mushrooms is yet unclear. In static liquid cultivation of Ganoderma lucidum for producing antitumor ganoderic acids (GAs), the Mn(2+) addition was performed. Addition of 10 mM Mn(2+) at the start of the static liquid cultivation resulted in 2.2-fold improvement of total GAs production. The expression levels of GA biosynthetic and Ca(2+) sensors' genes were up-regulated with Mn(2+) induction while down-regulated by adding cyclosporin A (calcineurin inhibitor), suggesting that higher GA production might result from calcineurin signal regulation. Intracellular Ca(2+) imaging and calcineurin inhibitor study revealed that addition of Mn(2+) led to Ca(2+) influx from medium to the cells to trigger calcineurin signals. Mn(2+) addition was therefore an efficient induction strategy for improving GAs production, whose regulation mechanism was via calcineurin signaling transduction.

Improvement of ganoderic acid production by fermentation of Ganoderma lucidum with cellulase as an elicitor

Two-stage cultivation of Ganoderma lucidum was performed for the enhanced production of ganoderic acid (GA). Cellulase was identified to be an effective elicitor for the improvement of GA production, and GA titer reached 1334.5mg/l compared to the control (779.6mg/l) using lactose as the substrate without cellulase addition. Loading of 5mg/l cellulase on day 3 resulted in the maximal GA titer of 1608mg/l. To our knowledge, this is the first time that cellulase was used as the elicitor to enhance GA production. Submerged fermentation in a 2.0-l bioreactor was also conducted with cellulase as the elicitor, and as a result the maximal GA titer of 1252.7mg/l was obtained on day 12. This is so far the best GA production obtained in submerged fermentation of G. lucidum.

Enhanced accumulation of individual ganoderic acids in a submerged culture of Ganoderma lucidum by the overexpression of squalene synthase gene

Ganoderic acids (GAs) produced by Ganoderma lucidum exhibit antitumor and antimetastasis activities. This study aimed to improve the production of individual GAs by engineering the biosynthetic pathway of GAs in G. lucidum through the overexpression of squalene synthase (SQS) gene. SQS catalyzes the first enzymatic step from the mevalonate pathway toward triterpene biosynthesis. The effects of SQS gene overexpression on the accumulation of individual GAs and their intermediates (squalene and lanosterol) by a submerged culture of G. lucidum and on the transcription levels of GA biosynthesis genes in this mushroom were investigated. The maximum contents of GA-Mk, GA-T, GA-Me, and GA-S in G. lucidum overexpressing the SQS gene were 16, 40, 43, and 53μg/100mg dry cell weight, respectively, which were 2.86-, 2.67-, 1.95-, and 1.25-fold of those obtained in wild-type strain (WT). The maximum contents of squalene and lanosterol in the SQS gene-overexpression strain were 1.55- and 1.68-fold higher than those of the WT strain. The transcription levels of the biosynthetic genes encoding SQS and lanosterol synthase were up-regulated by 15.6- and 1.93-fold, respectively, in G. lucidum overexpressing the SQS gene, suggesting that increased GA biosynthesis may result from a higher expression of those genes.

Screening of Ganoderma strains with high polysaccharides and ganoderic acid contents and optimization of the fermentation medium by statistical methods

Polysaccharides and ganoderic acids (GAs) are the major bioactive constituents of Ganoderma species. However, the commercialization of their production was limited by low yield in the submerged culture of Ganoderma despite improvement made in recent years. In this work, twelve Ganoderma strains were screened to efficiently produce polysaccharides and GAs, and Ganoderma lucidum 5.26 (GL 5.26) that had been never reported in fermentation process was found to be most efficient among the tested stains. Then, the fermentation medium was optimized for GL 5.26 by statistical method. Firstly, glucose and yeast extract were found to be the optimum carbon source and nitrogen source according to the single-factor tests. Ferric sulfate was found to have significant effect on GL 5.26 biomass production according to the results of Plackett-Burman design. The concentrations of glucose, yeast extract and ferric sulfate were further optimized by response surface methodology. The optimum medium composition was 55g/L of glucose, 14g/L of yeast extract, 0.3g/L of ferric acid, with other medium components unchanged. The optimized medium was testified in the 10-L bioreactor, and the production of biomass, IPS, total GAs and GA-T enhanced by 85, 27, 49 and 93%, respectively, compared to the initial medium. The fermentation process was scaled up to 300-L bioreactor; it showed good IPS (3.6g/L) and GAs (670mg/L) production. The biomass was 23.9g/L in 300-L bioreactor, which was the highest biomass production in pilot scale. According to this study, the strain GL 5.26 showed good fermentation property by optimizing the medium. It might be a candidate industrial strain by further process optimization and scale-up study.

Production of ganoderic acid by Ganoderma lucidum RCKB-2010 and its therapeutic potential

The newly isolated basidiomycetous fungus, identified as Ganoderma lucidum RCKB-2010 was tested for production of ganoderic acid (GA) under submerged fermentation conditions. Production of GA under liquid static cultivation condition was found to be 2,755.88 mg L−1 on the 25th day of incubation, whereas under shaking cultivation conditions the maximum production of GA was observed to be 373.75 mg L−1. 1H NMR analysis revealed clearly that the fungal extracts possessed a lanostane skeleton, confirming the presence of GA. Interestingly, GA was found to have potential to inhibit the proliferation of HeLa cells and U87 human glioma cells in a dose dependent manner. In addition, GA was also found to possess antibacterial activity, exhibiting a minimal inhibitory concentration of 0.25 mg mL−1 against standard strains of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis. GA produced in the present study holds potential as a potent anticancer agent.

Oxygen limitation improves ganoderic acid biosynthesis in submerged cultivation of Ganoderma lucidum

The effects of oxygen limitation on the production of ganoderic acid (GA), a secondary metabolite with antitumor activity, and on transcription levels of triterpene biosynthesis genes were investigated in liquid cultures of Ganoderma lucidum. A low oxygen supply level was beneficial to total GA biosynthesis, but negative to the cell growth. The higher GA production was obtained under micro-aerobic conditions (i.e. initial overall kLa values at 0.02 and 0.13/h). The maximum GA production of 272.3 ± 11.5 mg/L was obtained at an initial overall kLa of 0.13/h, which was 1.7-fold that at a normal cultivation condition (an initial kLa of 5.51/h). For four major individual GAs, the production level of GA-Mk, -T, -S, and -Me in the hypoxia-induced cells was increased by 50, 87, 62, and 111%, compared with that of the control, respectively. Meanwhile, the transcriptions of four key genes encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase, mevalonate-5-pyrophosphate decarboxylase, squalene synthase and squalene epoxidase in the triterpene biosynthetic pathway were up-regulated under the hypoxia condition (at an initial kLa of 0.13/h). Reactive oxygen species was generated in response to hypoxia, which seemed to be involved in the regulation of GA biosynthesis. The information obtained provides an insight into the role of oxygen limitation in the GA biosynthesis, and will be helpful for optimizing the fermentation process on a large scale.

Induced effect of Na+ on ganoderic acid biosynthesis in static liquid culture of Ganoderma lucidum via calcineurin signal transduction

Na(+)/Ca(2+) exchange is important to cell physiology and metabolism, but its role in the secondary metabolite biosynthesis by fungi is yet unclear. In this work, in static liquid cultures of Ganoderma lucidum, which is an efficient process for hyper-production of anti-tumor ganoderic acids (GAs), it was interestingly found that Na(+) addition could enhance the GAs production, but K(+) did not. Further investigation by intracellular Ca(2+) imaging and using a calcineurin inhibitor (i.e., cyclosporin A) revealed that addition of Na(+) led to the influx of Ca(2+) from culture broth to the cells and calcineurin signals were also triggered. Addition of 100 mM Na(+) at the beginning of the static liquid cultivation, in which the addition dosage and timing were optimized, resulted in 2.8-fold improvement of total GAs production. Quantitative gene transcription analysis indicated that the expression levels of the genes of Ca(2+) sensors and GA biosynthesis were upregulated with Na(+) induction while downregulated by using the calcineurin inhibitor, implying that higher GA production might result from higher expression of those genes. This work not only provided a simple and efficient induction strategy by Na(+) addition for the improved GAs production but also suggested the regulation mechanism of Na(+) on the GA biosynthesis through calcineurin signaling transduction.

A Novel Approach to Enhancing Ganoderic Acid Production by Ganoderma lucidum Using Apoptosis Induction

Ganoderma lucidum is one of most widely used herbal medicine and functional food in Asia, and ganoderic acids (GAs) are its active ingredients. Regulation of GA biosynthesis and enhancing GA production are critical to using G. lucidum as a medicine. However, regulation of GA biosynthesis by various signaling remains poorly understood. This study investigated the role of apoptosis signaling on GA biosynthesis and presented a novel approach, namely apoptosis induction, to increasing GA production. Aspirin was able to induce cell apoptosis in G. lucidum, which was identified by terminal deoxynucleotidyl transferase mediated dUPT nick end labeling assay positive staining and a condensed nuclear morphology. The maximum induction of lanosta-7,9(11), 24-trien-3α-01-26-oic acid (ganoderic acid 24, GA24) production and total GA production by aspirin were 2.7-fold and 2.8-fold, respectively, after 1 day. Significantly lower levels of GA 24 and total GAs were obtained after regular fungal culture for 1.5 months. ROS accumulation and phosphorylation of Hog-1 kinase, a putative homolog of MAPK p38 in mammals, occurred after aspirin treatment indicating that both factors may be involved in GA biosynthetic regulation. However, aspirin also reduced expression of the squalene synthase and lanosterol synthase coding genes, suggesting that these genes are not critical for GA induction. To the best of our knowledge, this is the first report showing that GA biosynthesis is linked to fungal apoptosis and provides a new approach to enhancing secondary metabolite production in fungi.

Effect of solid-medium coupled with reactive oxygen species on ganoderic acid biosynthesis and MAP kinase phosphorylation in Ganoderma lucidum

Ganoderma lucidum is used as a functional food and medicinal mushroom in Asia. Biosynthesis of its active ingredients, the ganoderic acids (GAs), together with signal transduction related to the fungal biology of G. lucidum, are critical for this application. However, regulation of G. lucidum GA biosynthesis and signal transduction remains enigmatic. We investigated the role of reactive oxygen species (ROS) on biosynthesis of individual GAs and on MAPK (mitogen-activated protein kinase) signaling. Antioxidant treatment decreased lanosta-7,9(11), 24-trien-3α-01-26-oic acid (ganoderic acid 24) and total GA production. Cultures incubated with the pro-oxidant CDNB (1-chloro-2,4-dinitrobenzene) or H2O2, increased production of ganoderic acid 24 and total GAs were found. Interestingly, CDNB reduced RNA expression of the squalene synthase and lanosterol synthase, indicating that both genes may not be bottlenecks in GA induction. H2O2 induced phosphorylation of the proteins Hog-1 and Fus3, which are homologs of the mammalian MAPKs p38 and ERK (extracellular signal-related kinases), respectively. CDNB also enhanced phosphorylation of Hog1 but had no effect on Fus3. To the best of our knowledge, this is the first report indicating that ROS regulate the biosynthesis of individual GAs and affect MAPK signaling in G. lucidum. This study also identifies the potential application of ROS to the G. lucidum functional food industry.

Enhanced Production of Ganoderic Acids and Cytotoxicity ofGanoderma lucidumUsing Solid-Medium Culture

Submerged cultures of Ganoderma lucidum are used to produce fungal mycelium, which is used as a functional food and in the production of various triterpenoids, including ganoderic acids (GAs). Specific culture approaches that produce fungal mycelium with high levels of GAs and good biological activity are critical in the functional food industry. In this study, a solid-medium culture approach to producing mycelium was compared to the submerged culture system. Production of GAs, biomass, intracellular polysaccharides, and cytotoxicity of the cultured mycelium were compared as between solid and submerged culture. Growing G. lucidum strains on solid potato dextrose agar medium increased biomass, the production of ganoderic acid 24 (lanosta-7,9(11), 24-trien-3α-o1-26-oic acid), GAs, and total intracellular polysaccharides as compared to fungi grown in submerged culture. Triterpenoid-enriched methanol extracts of mycelium from solid-medium culture showed higher cytotoxicity than those from submerged culture. The IC(50) values of methanol extracts from solid-medium culture were 11.5, 8.6, and 9.9 times less than submerged culture on human lung cancer cells CH27, melanoma cells M21, and oral cancer cells HSC-3 respectively. The squalene synthase and lanosterol synthase coding genes had higher expression on the culture of solid potato dextrose medium. This is the first report that solid-medium culture is able to increase GA production significantly as compared to submerged culture and, in the process, produces much higher biological activity. This indicates that it may be possible to enhance the production of GAs by implementing mycelium culture on solid medium.

Production of Biomass, Polysaccharides, and Ganoderic Acid using Non-conventional Carbon Sources under Submerged Culture of the Lingzhi or Reishi Medicinal Mushroom, Ganoderma lucidum (W.Curt.:Fr.)P. Karst. (Higher Basidiomycetes)

The effect of different non-conventional carbon sources was studied in the submerged culture of Lingzhi or Reishi medicinal mushroom, Ganoderma lucidum, for simultaneous production of mycelial biomass, bioactive ganoderic acid, and polysaccharides, in less time, using non-conventional carbon sources to minimize the high costs of current culture media. The optimal medium composition was defined as (g/L): 50 of barley flour, 0.2 of KH2PO4, 0.1 of MgSO4ⁱ7H2O, and 1 NH4Cl. Cultivated under this complex culture medium, the mycelial biomass production was 23.49 ± 0.37 g/L; the extracellular polysaccharides production was 2.72 ± 0.11 g/L; the intracellular polysaccharides production was 2.22 ± 0.06 g/L; the ganoderic acids production was 299.67 ± 11.63 mg/L. One liter of culture medium developed in this project was priced at USD $ 0.11 if barley flour is used as carbon source or $ 0.13 with oat flour in order to get a good amount of products of interest.

Submerged Cultivation of Medicinal Mushrooms: Bioprocesses and Products (Review)

Medicinal mushrooms belonging to higher Basidiomycetes are an immensely rich yet largely untapped resource of useful, easily accessible, natural compounds with various biological activities that may promote human well-being. The medicinal properties are found in various cellular components and secondary metabolites (polysaccharides, proteins and their complexes, phenolic compounds, polyketides, triterpenoids, steroids, alkaloids, nucleotides, etc.), which have been isolated and identified from the fruiting bodies, culture mycelium, and culture broth of mushrooms. Some of these compounds have cholesterol-lowering, anti-diabetic, antioxidant, antitumor, immunomodulating, antimicrobial, and antiviral activities ready for industrial trials and further commercialization, while others are in various stages of development. Recently, the submerged cultivation of medicinal mushrooms has received a great deal of attention as a promising and reproducible alternative for the efficient production of mushroom mycelium and metabolites. Submerged cultivation of mushrooms has significant industrial potential, but its success on a commercial scale depends on increasing product yields and development of novel production systems that address the problems associated with this technique of mushroom cultivation. In spite of many researchers' efforts for the production of bioactive metabolites by mushrooms, the physiological and engineering aspects of submerged cultures are still far from being thoroughly studied. The vast majority of studies have focused on polysaccharide and ganoderic acid production in submerged cultivation of medicinal mushrooms, and very little has been written so far on the antioxidant and hemagglutinating activity of submerged mushroom cultures. The purpose of this review is to provide an update of the present state of the art and future prospects of submerged cultivation of medicinal mushrooms to produce mycelium and bioactive metabolites, and to make a contribution for the research and development of new pharmaceutical products from mushrooms. A brief overview of the metabolic diversity and bioactive compounds of mushrooms produced by submerged cultures is also given.

Isolation and characterization of a novel Ganoderma lucidum gene that differentially expressed between shaking culture and liquid static culture

Suppression subtractive hybridization (SSH) was preformed to investigate the differences of gene expression between the shaking culture mode and the liquid static culture mode which favors ganoderic acids production in Ganoderma lucidum. One novel gene preferentially expressed in liquid static culture was identified and analyzed. Its full length cDNA sequence and the 5′-flanking region were then obtained by rapid amplification of cDNA ends (RACE) and self-formed adaptor PCR (SEFA-PCR), respectively. Nucleotide sequence of the gene is not homologous to any of the known Ganoderma genes. The sequence analysis revealed that the open reading frame of this gene encodes a protein of 371 amino acids that has high homology with the mitogen-activated protein kinase (MAPK) of other five species-Postia (97%), Coprinopsis (91%), Neurospora (86%), Aspergillus (83%), and Saccharomyces (80%)-so that it can be defined as a G. lucidum MAPK gene (GenBank accession number: JF781125). Computer assisted analysis revealed that this new G. lucidum MAPK gene contains thirteen exons and twelve introns. The quantitative real-time RT-PCR (qRT-PCR) analysis showed that this new gene had a much higher expression level in liquid static culture than in traditional shaking culture. Results of this research established a good foundation for further study on the functions of the G. lucidum MAPK at the molecular level.

Impacts of calcium signal transduction on the fermentation production of antitumor ganoderic acids by medicinal mushroom Ganoderma lucidum

Recently signal transduction engineering of secondary metabolism is receiving great interest as a powerful tool towards efficient production of valuable secondary metabolites. This work found that the calcineurin-signal transduction was significant to triterpene biosynthesis by higher fungus (mushroom). Addition of calcium ion (at 10mM) to static liquid cultures of Ganoderma lucidum, a famous traditional medicinal mushroom, was proved as a useful strategy to enhance the production of antitumor ganoderic acids (GAs), which resulted in 3.7-, 2.6-, 4.5-, 3.2- and 3.8-fold improvement of total GAs, individual GA-Mk, -T, -S, and -Me, respectively. Experiments using Ca2+ sensor inhibitors indicated the involvement of calcineurin signal in regulating GAs biosynthesis. Quantitative gene transcription analysis revealed that the expression levels of genes of GAs biosynthesis and Ca2+ sensor were up-regulated with calcium addition while down-regulated under the inhibitors addition, suggesting that higher GAs production may be resulted from higher expressions of those genes. Based on the results obtained, a possible model on the effect of external calcium ion on the GAs biosynthesis via calcineurin signal transduction pathway was proposed.