• Journal of Microbiology and Biotechnology
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• v.31 no.6
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• pp.855-866
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• 2021

The effects of various carbon sources on mycelial growth and polysaccharide synthesis of the medicinal fungus Inonotus obliquus in liquid fermentation were investigated. After 12-d fermentation, mycelial biomass, polysaccharide yield, and polysaccharide content were significantly higher in Glc+Lac group (glucose and lactose used as combined carbon source) than in other groups. Crude polysaccharides (CIOPs) and the derivative neutral polysaccharides (NIOPs) were obtained from mycelia fermented using Glc, fructose (Fru), Lac, or Glc+Lac as carbon source. Molecular weights of four NIOPs (termed as NIOPG, NIOPF, NIOPL, and NIOPGL) were respectively 780.90, 1105.00, 25.32, and 10.28 kDa. Monosaccharide composition analyses revealed that NIOPs were composed of Glc, Man, and Gal at different molar ratios. The NIOPs were classified as α-type heteropolysaccharides with 1→2, 1→3, 1→4, 1→6 linkages in differing proportions. In in vitro cell proliferation assays, viability of RAW264.7 macrophages was more strongly enhanced by NIOPL or NIOPGL than by NIOPG or NIOPF, and proliferation of HeLa or S180 tumor cells was more strongly inhibited by NIOPG or NIOPGL than by NIOPF or NIOPL, indicating that immune-enhancing and anti-tumor activities of NIOPs were substantially affected by carbon source. qRT-PCR analysis revealed that expression levels of phosphoglucose isomerase (PGI) and UDP-Glc 4-epimerase (UGE), two key genes involved in polysaccharide synthesis, varied depending on carbon source. Our findings, taken together, clearly demonstrate that carbon source plays an essential role in determining structure and activities of I. obliquus polysaccharides by regulating expression of key genes in polysaccharide biosynthetic pathway.

• Microbiology and Biotechnology Letters
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• v.39 no.4
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• pp.357-363
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• 2011

This study focus was primarily the development of liquid starters for Aspergillus oryzae and Aspergillus niger prepared with wheat bran as a low cost culture medium. For the preparation of the liquid media wheat bran was added at rates of 0, 5, 10, 15 and 20% and the Aspergillus sp. strains were then inoculated to these prepared broths. The results indicated that the more that wheat bran was contained in the medium, the more mycelia was produced for A. oryzae and A. niger. The highest enzyme activities were obtained with a 10~15% adding rate of wheat bran for both strains. Changes in the enzyme activities of the liquid starters during various incubation times (0, 24, 48, 72 and 96 hrs), indicated that the highest enzyme activities were seen between 48 and 72 hrs of culture. In addition, a comparative study was carried out on the production of enzymes using wheat as a substrate in nuruk, with liquid starter made from fermented agents according to the same concentrations used with the wheat bran. The pH, acidity, amino acidity, reducing sugar content and enzyme activity (${\alpha}$-amylase, glucoamylase, acidic protease) of wheat nuruk made with liquid starter were compared with those of wheat nuruk made with solid starter. The results suggest that the liquid starter is superior in both cases.

• Korean Journal of Agricultural Science
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• v.31 no.1
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• pp.15-25
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• 2004

In order to determine the effect of fermentation by the mycelia of fungal species, Formitella fraxinea and Sarcodon aspratus, on the in vitro dry matter digestibility and pH of mixtures with sawdust plus 20% wheat bran w/w, on dry matter basis to use as a feedstuff or an additive including fungal mycelium into a feedstuff. The mixtures were unfermented (UF) and fermented by Formitella fraxinea(FF) and Sarcodon aspratus(SA) for two weeks at $29^{\circ}C$ in a incubator. Fungal fermentation products were added to the basal diet to the level of 0, 1, 3 and 5%, w/w of diets each. The in vitro dry matter digestibilities, soluble sugar contents and pH of fermentation fluids were measured at 24, 48 and 72hr after fermentation begin. Neutral detergent fiber(NDF) contents in mixtures were lower for SA and UF(80.4 and 82.2%) than for FF(88.3%) (P<0.05). In vitro DM digestibility for 48h was higer for SA(21.2%) than for UF and FF(17.9 and 12.2%). The in vitro dry matter digestibility for 24hr was higher for diets added with FF 1% as 49.18%, and lower for diet added with FF 5%(43.07%) than basal diet(44.98%)(P<0.05), and tended to be higher for the diets added with fungal products. The pH of in vitro fermentation fluids for 24 and 48 hrs fermentation were lower for diets added with all FF and SA than for UF(P<0.05). However, those for 72 hrs fermentation were higher for SA 1%(6.74) than other diets(P<0.05). The soluble sugar concentration of in vitro fermentation fluid was not different between diets for 24 hr fermentation. However, those were higher for all additive diets than basal diet for 48 and 72 hrs fermentation(P<0.05). It could be concluded that dairy cow's diets added with fungal fermentation products have positive effects, and expected it will be more beneficial if more fungal mycelium was contained.

• Journal of Korean Society of Forest Science
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• v.64 no.1
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• pp.11-19
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• 1984

Potted, germinating Pinus rigida ${\times}$ P. taeda seedlings were inoculated with Pisolithus tinctorius (Pt) ectomycorrhizal fungus to test the effectiveness of Pt in relation to organic amendment and changes in soil fertility and soil texture. Pt was cultured as mycelia in vermiculite-peat moss mixture with nutrients and added to sterilized pot soils with or without organic amendment (fully fermented compost) at three soil texture levels (sand, loamy sand, and sandy loam) in a factorial design. Plants were grown in a greenhouse for 4 months and harvested to compare their growth with non-mycorrhizal plants and plants infected by natural fungi. Regardless of sod texture, soil fertility, or organic amendment, seedlings inoculated with Pt were better in dry weight and height than non-mycorrhizal plants or those infected by natural fungi. An exception was observed in the most fertile soil (0.075% N and 1.32% organic matter content in sandy loam with organic amendment), where non-mycorrhizal plants were slightly bigger (8%) and heavier (18%) than Pt-inoculated plants. In over-all average, Pt-inoculated seedlings were 30% taller and 107% heavier than those infected by natural fungi and 31 % taller and 60% heavier than non-mycorrhizal plants. Growth stimulation of seedlings by Pt was more pronounced in less fertile sand soil when organic was not amended. Mycorrhizal frequency of Pt (% of mycorrhizal root tips) was reduced to about half (from 84 to 33% in sandy loam and from 77 to 40% in loamy sand) by organic amendment, while that of natural fungi was not significantly affected. Severe nitrogen deficiency was observed in the needles of non-mycorrhizal plants (1.38% N), while both Pt-inoculated plants (1.68% N) and those infected by natural fungi (1.89% N) did not develop symptom, suggesting an active role of mycorrhizae in absorption of soil nitrogen. Top to root ratio increased with organic amendment to non-mycorrhizal plants, but was not significantly affected by fungal treatment. It was concluded from this study that relative effectiveness of Pt was determined by soil fertility. Organic amendment to less fertile sand soil increased effectiveness of Pt, while the same amendment to more fertile loamy sand and sandy loam decreased effectiveness of Pt. Benefits of Pt mycorrhizae would be expected most either when organic was not added to the soil, or when soil nutrients were not abundant.