Adding-value to Ganoderma lingzhi by producing enzymes and antioxidant compounds under submerged fermentation using different culture media.

Ganoderma lingzhi is widely reported for its medicinal properties, presenting several bioactive substances with potential pharmaceutical and industrial application. This study aimed to evaluate the production of mycelial biomass, extracellular enzymes and antioxidant compounds by G. lingzhi under submerged fermentation. G. lingzhi was cultured in Polysaccharide (POL) and Melin-Norkrans (MNM) media for 7 days. The cellulases, xylanases, pectinases, laccases, and proteases activities were quantified in the culture broth, while the antioxidant potential was evaluated for the mycelial biomass. G. lingzhi showed higher biomass production in MNM. However, it exhibited similar microstructural characteristics in both culture media. In the POL there was greater activity of CMCase (0.229 U/mL), xylanase (0.780 U/mL), pectinase (0.447 U/mL) and proteases (16.13 U/mL). FPase did not differ (0.01 U/mL), and laccase was detected only in MNM (0.122 U/mL). The biomass water extract from MNM showed high levels of phenolic compounds (951.97 mg AGE/100 g). DPPH• inhibition (90.55%) and reducing power (0.456) were higher in MNM medium, while ABTS•+ inhibition (99.95%) and chelating ability (54.86%) were higher in POL. Thus, the MNM medium was more favorable to the production of mycelial biomass and phenolic compounds, while the POL medium favored the synthesis and excretion of hydrolytic enzymes.

Kinetics Analysis of the Inhibitory Effects of Alpha-Glucosidase and Identification of Compounds from Ganoderma lipsiense Mycelium.

The studies on natural compounds to diabetes mellitus treatment have been increasing in recent years. Research suggests that natural components can inhibit alpha-glucosidase activities, an important strategy in the management of blood glucose levels. In this work, for the first time in the literature, the compounds produced by Ganoderma lipsiense extracts were identified and evaluated on the inhibitory effect of these on alpha-glucosidase activity. Four phenolic compounds were identified by high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (HPLC-ESI-MS/MS) to crude extract from G. lipsiense grown in red rice medium (RCE) and synthetic medium (SCE), being syringic acid identified in both extracts. Gas chromatography-mass spectrometry (GC-MS) analysis showed fatty acids and their derivatives, terpene, steroid, niacin, and nitrogen compounds to SCE, while RCE was rich in fatty acids and their derivatives. Both extracts demonstrated alpha-glucosidase inhibition (RCE IC50 = 0.269 ± 8.25 mg mL-1; SCE IC50 = 0.218 ± 9.67 mg mL-1), and the purified hexane fraction of RCE (RHEX) demonstrated the highest inhibition of enzyme (81.1%). Studies on kinetic inhibition showed competitive inhibition mode to RCE, while SCE showed uncompetitive inhibition mode. Although the inhibitory effects of RCE and SCE were satisfactory, the present findings identified some unpublished compounds to G. lipsiense in the literature with important therapeutic properties.

Biodegradation of polycyclic aromatic hydrocarbons by native Ganoderma sp. strains: identification of metabolites and proposed degradation pathways.

Since polycyclic aromatic hydrocarbons (PAHs) are mutagenic, teratogenic, and carcinogenic, they are of considerable environmental concern. A biotechnological approach to remove such compounds from polluted ecosystems could be based on the use of white-rot fungi (WRF). The potential of well-adapted indigenous Ganoderma strains to degrade PAHs remains underexplored. Seven native Ganoderma sp. strains with capacity to produce high levels of laccase enzymes and to degrade synthetic dyes were investigated for their degradation potential of PAHs. The crude enzymatic extracts produced by Ganoderma strains differentially degraded the PAHs assayed (naphthalene 34-73%, phenanthrene 9-67%, fluorene 11-64%). Ganoderma sp. UH-M was the most promising strain for the degradation of PAHs without the addition of redox mediators. The PAH oxidation performed by the extracellular enzymes produced more polar and soluble metabolites such as benzoic acid, catechol, phthalic and protocatechuic acids, allowing us to propose degradation pathways of these PAHs. This is the first study in which breakdown intermediates and degradation pathways of PAHs by a native strain of Ganoderma genus were determined. The treatment of PAHs with the biomass of this fungal strain enhanced the degradation of the three PAHs. The laccase enzymes played an important role in the degradation of these compounds; however, the role of peroxidases cannot be excluded. Ganoderma sp. UH-M is a promising candidate for the bioremediation of ecosystems polluted with PAHs.

Combined effect of enzyme inducers and nitrate on selective lignin degradation in wheat straw by Ganoderma lobatum.

Lignin is one of the main barriers to obtaining added-value products from cellulosic fraction of lignocellulosic biomass due to its random aromatic structure and strong association with cellulose and hemicellulose. Inorganic and organic compounds have been used as enzyme inducers to increase the ligninolytic potential of white-rot fungi, without considering their effect on the selectivity of degradation. In this study, the selective lignin degradation in wheat straw by Ganoderma lobatum was optimized using a central composite design to evaluate the combined effect of Fe2+ and Mn2+ as inducers of ligninolytic enzymes and NO3- as an additional nitrogen source. Selective lignin degradation was promoted to maximize lignin degradation and minimize weight losses. The optimal conditions were 0.18 M NO3-, 0.73 mM Fe2+, and 1 mM Mn2+, which resulted in 50.0% lignin degradation and 18.5% weight loss after 40 days of fungal treatment. A decrease in absorbance at 1505 and 900 cm-1 in fungal-treated samples was observed in the FTIR spectra, indicating lignin and cellulose degradation in fungal-treated wheat straw, respectively. The main ligninolytic enzymes detected during lignin degradation were manganese-dependent and manganese-independent peroxidases. Additionally, confocal laser scanning microscopy revealed that lignin degradation in wheat straw by G. lobatum resulted in higher cellulose accessibility. We concluded that the addition of enzyme inducers and NO3- promotes selective lignin degradation in wheat straw by G. lobatum.

Studies towards the stabilisation of a mushroom phytase produced by submerged cultivation.

A novel phytase from Ganoderma australe G24 was produced by submerged cultivation and recovery. Liquid and solid forms of phytase were developed; both types of product were formulated using different additives. Ganoderma australe G24 phytase was very stable in liquid form with NaCl and sodium acetate buffer. Solid form products were obtained by spray-drying using different polymers to encapsulate the phytase and the capsules obtained were analyzed by electron microscopy. Micrographs confirmed micro and nanoparticles formed with maltodextrin (300 nm to 7-8 µm) without the presence of agglomerates. The use of maltodextrin for solid formulation of G. australe G24 phytase is recommended, and resulted in good stability after the drying process and during storage (shelf life). Kinetic models of phytase inactivation in the microencapsulated powders over time were proposed for the different stabilizing additives. Inactivation rate constants, half-lives and D values (decimal reduction time) were obtained. Phytase encapsulated with maltodextrin remained stable after 90 days, with k 0.0019 day(-1) and a half-life (t1/2) of 367.91 days(-1).

Analysis of inducers of xylanase and cellulase activities production by Ganoderma applanatum LPB MR-56.

This manuscript describes the analysis of the effect of cellulose, carboxymethylcellulose (CMC), xylan, and xylose as inducers of cellulase and xylanase activity production by Ganoderma applanatum MR-56 and the optimization of their production in liquid cultures by statistical methods. The Plackett-Burman screening design was applied to identify the most significant inducers of xylanase and cellulase activities production by G. applanatum MR-56. The most significant effect on xylanase and cellulase activities production was exercised by cellulose, even if xylose and CMC were also effective at some times. The combined effect of cellulose, yeast extract, and pH was analyzed by a 2(3) factorial experimental design with four central points that showed that the maximum tested cellulose (1 % w/v) and yeast extract (5 g L(-1)) concentrations gave the maximum production of xylanase (8.24 U mL(-1)) and cellulase (3.29 U mL(-1)) activity at pH 6 and 4, respectively. These values achieved for cellulase and xylanase activity represent 12-25 fold and 36 fold higher values than the maximum so far reported for other strains of G. applanatum, respectively.

Evaluation of the white-rot fungi Ganoderma australe and Ceriporiopsis subvermispora in biotechnological applications.

Ganoderma australe is a white-rot fungus that causes a selective wood biodelignification in some hardwoods found in the Chilean rainforest. Ceriporiopsis subvermispora is also a lignin-degrading fungus used in several biopulping studies. The enzymatic system responsible for lignin degradation in wood can also be used to degrade recalcitrant organic pollutants in liquid effluents. In this work, two strains of G. australe and one strain of C. subvermipora were comparatively evaluated in the biodegradation of ABTS and the dye Poly R-478 in liquid medium, and in the pretreatment of Eucalyptus globulus wood chips for further kraft biopulping. Laccase was detected in liquid and wood cultures with G. australe. Ceriporiopsis subvermispora produce laccase and manganese peroxidase when grown in liquid medium and only manganese peroxidase was detected during wood decay. ABTS was totally depleted by all strains after 8 days of incubation while Poly R-478 was degraded up to 40% with G. australe strains and up to 62% by C. subvermispora after 22 days of incubation. Eucalyptus globulus wood chips decayed for 15 days presented 1-6% of lignin loss and less than 2% of glucan loss. Kraft pulps with kappa number 15 were produced from biotreated wood chips with 2% less active alkali, with up to 3% increase in pulp yield and up to 20% less hexenuronic acids than pulps from undecayed control. Results showed that G. australe strains evaluated were not as efficient as C. subvermispora for dye and wood biodegradation, but could be used as a feasible alternative in biotechnological processes such as bioremediation and biopulping.