• Journal of Microbiology and Biotechnology
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• v.8 no.5
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• pp.543-546
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• 1998

The effect of glucose concentration on the production of erythritol by Trichosporon sp. was mainly studied. The specific growth rate and production rate of erythritol gave the highest values of $0.23 h^{-1}\; and\; 4.2 g/\ell/h,\; respectively,\; on\; 100 g \; glucose/\ell$ of medium. The conversion yield of erythritol during the exponential phase and the stationary phase was constantly maintained at 19% and 51 %, respectively, while the glucose concentration in the medium varied from 100 g/$\ell$ to 400 g/$\ell$. The maximum overall erythritol conversion yield of 47% was obtained when the glucose concentration in the medium was 400 g/$\ell$. It corresponded to a 74% increase compared with the 100 g/$\ell$ glucose medium. The diauxy growth of this microbe was also observed. It grew exponentially consuming glucose, then after the second lag phase, biomass slowly increased using glycerol and erythritol.

• Journal of Microbiology and Biotechnology
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• v.11 no.6
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• pp.951-956
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• 2001

A 28-kDa extracellular lipase (pI 8.7) was purified to homogeneity from the culture supernatant of Trichosporon sp. Y- 11 by mmonium sulfate precipitation, DEAE-Sephadex A-50, Bio-Gel P-30, CM- Sephadex C-50, and Bio-Gel P- 10 chromatographies. The purified enzyme exhibited a specific activity of $2,741{\;}{\mu}mol/min/mg$ based on the hydrolysis of triolein, and the optimal hydrolysis activity was dentified at pH 8.0 and $40^{\circ}C$. The enzyme activity was inhibited by $Ag^+$ and enhanced by $Fe^{2+}$, $Fe^{3+}$, $Mg^{2+}$, $Mn^{2+}$, and $Li^{+}$. The enzyme activity exhibited for the hydrolysis of both tributyrin and trilinolein. The ester synthesis of unsaturated fatty acids with various alcohols catalyzed by the purified lipase in a nonaqueous medium or microaqueous system was also investigated. The esterification activity of the lipase increased with an increase of the carbon chain length in the alcohol. The synthesis rate of linoleic acid and oleyl alcohol was the highest with an optimal temperature and pH of $40^{\circ}C$ and 8.0, respectively. The water content and agitation also affected the esterification activity of the lipase.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.180-186
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• 1991

A water soluble antifungal antibiotic, Solumycin, was separated from the culture broth of Streptomyces sp. LAM-593, isolated from soil, by butanol extraction, alumina-, 1st and 2nd Sephadex LH-20 column chromatography. The substance was pale yellow crystal which gave a single spot at Rf value 0.24 with ethanol-ammonia water-water (8:1:1), 0.46 with butanol-ethanol-water (5:1:4), 0.84 with 50% methanol on silica gel TLC. It was dissolved well in water, methanol and acidic aq. butanol but not in ethanol, acetone, ethyl acetate, chloroform. acetic acid etc., and gave positive Fehling and Molish reaction. The UV spectrum in methanol showed absorption at 342, 361, 380, and 404 nm. The antibiotic was active against fungi such as Candide, Cryptococcus, Saccharomyces, Trichophyton and Trichosporon, but not to bacteria such as Bacillus, Escherichia and Staphylococcus.

• Asian-Australasian Journal of Animal Sciences
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• v.32 no.7
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• pp.996-1006
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• 2019

Objective: This study aimed to gain deeper insights into the dynamic changes in spoilage fungi populations during fermentation and the influence of traditional additives on silage quality. Methods: Elephant grass (Pennisetum purpureum) was prepared without any additive (control), and with the addition of 0.5% salt, and 0.5% salt-0.2% sugar mixture. The fungal community was then determined using a classic culturing method and high-throughput sequencing at 0, 5, 15, and 60 days after ensiling. Results: The results showed that the fungal community of elephant grass silage varied significantly between the natural fermentation without any additive and the two additive groups. The diversity and relative abundance of spoilage molds in the control group were much higher than those in the two treatment groups (p<0.05). Three species of yeasts (Candida sp., Pichia sp., Trichosporon sp.) and four spoilage molds (Fusarium sp., Aspergillus sp., Muco sp. and Penicillin sp.) were the predominant fungi in elephant grass during natural fermentation from 0 to 60 days, which were found to be significantly decreased in salt and sugar additive groups (p<0.05). Meanwhile, the diversity and relative abundance of undesirable molds in the 0.5%-salt additive group were the lowest among all groups. Conclusion: Adding salt and sugar, particularly 0.5% salt, is a promising effective approach to reduce the amount of undesirable fungi thus, improving the silage quality of elephant grass in northern Vietnam.