• KSBB Journal
• /
• v.22 no.1
• /
• pp.1-6
• /
• 2007

The optimum liquid culture conditions were investigated for cell growth and polysaccharide production from liquid culture of Lentinus edodes. In flask culture, the optimal medium compositions for the polysaccharide production contained glucose 60 g/L, yeast extract 10 g/L, $KH_2PO_4$ 2.0 g/L, and $MgSO_4{\cdot}7H_2O$ 1.0 g/L. The maximum mycelial growth and polysaccharide production were 11.01 g/L and 1.64 g/L, respectively. In bioreactor, through the variation of aeration in order to increase mycelial growth and polysaccharide production, the maximum mycelial growth and polysaccharide production were 55.9 g/L at 8th day and 7.34 g/L at 7th day of cultivation with 1.5 vvm, respectively.

• Microbiology and Biotechnology Letters
• /
• v.17 no.3
• /
• pp.247-251
• /
• 1989

Effects of mineral salts on sisomicin fermentation were investigated. The optimal concentration of CoCl$_2$for accomplishing a high antibiotic yield was found to be 16.8 $\mu$M at which it could function as a cofactor. At this level the other mineral salts tested had no effect. On the other hand, at much higher concentration levels (above 1 mM), four mineral salts such as ZnSO$_4$, KH$_2$PO$_4$, FeSO$_4$and MgSO$_4$were used in order to liberate the intracellular sisomicin out-side the cells, because the sisomicin accumulated mostly in cells and it was supposed to limit the improvement of antibiotic yield. ZnSO$_4$and KH$_2$PO$_4$had no effect at all, and FeSO$_4$brought about some improvement. However, by keeping the concentration of MgSO$_4$to be 25 mM or higher in culture broths, the antibiotic yield could be improved by more than 100%, partially due to the enhanced liberation of the intracellular antibiotic.

• Korean Journal of Microbiology
• /
• v.48 no.2
• /
• pp.141-146
• /
• 2012

A gene encoding the xylanase (XynA) predicted from partial genomic sequence of Paenibacillus woosongensis was cloned into Escherichia coli by PCR. This xynA gene consisted of 633 nucleotides, encoding a polypeptide of 211 amino acid residues. The deduced amino acid sequence exhibited 85-89% identity with those of several Paenibacillus xylanases, belonging to the glycosyl hydrolase family 11. As a results of expression of the structural gene by T7 promoter of a pET23a(+) expression vector, xylanase activity was higher in cell-free extract than culture filtrate of a recombinant Escherichia coli BL21(DE3) CodonPlus. However, the expression level of xylanase was not sufficient be detected by SDS-PAGE. The cell-free extract showed maximal xylanase activity at $60^{\circ}C$ and pH 5.5. The predominant products resulting from xylan and xylooligosaccharide hydrolysis were xylose and xylotriose. The enzyme could hydrolyze xylooligosaccharides larger than xylbiose.

• Microbiology and Biotechnology Letters
• /
• v.6 no.4
• /
• pp.155-159
• /
• 1978

Phenol utilizing yeast No. 558 isolated from soil sewage sediment was able to use substantial amount of phenol as the sole carbon source, and the biomass productivity by this organism was very excellent. This organism could grow well in 1000 ppm of phenol concentration, the maxim-um specific growth rate obtainable at pH 5.0, 3$0^{\circ}C$ was 0.27/hr., and the biomass yield coefficient Y vs. consumed phenol was 3.2. Maximum production rate of biomass was observed at 35$^{\circ}C$, pH 3.5 to pH 4.5, and the addition of the 0.005~0. 01% yeast extract was the most effective. Addition of HgCl$_2$ and phenyl hydrazine, inhibitors of oxide-reductase, in the phenol containing cultural liquid caused this organism no-growth at the concentration of 10$^{-5}$ M, 10$^{-3}$ M respectively. This organism could utilize not only phenol but catechol, resorcinol and benzidine.

• Journal of the Korean Wood Science and Technology
• /
• v.33 no.1 s.129
• /
• pp.48-57
• /
• 2005

Phthalate esters are known as plasticizers and some of them suspected as endocrine disrupting chemicals. In this study, in order to identify the mechanism of phthalate esters degradation by white rot fungus, phthalic acid, which is major metabolite in the biodegradation of phthalate esters, was used. Phthalic acid 50 ppm was treated in culture medium with Polyporus brumalis. The availability of ABTS oxidation was different from control and phthalic acid treated group after 4 days of incubation. The activity was gradually increased in control group, but not in phthalic acid treated group. Especially, esterase activity of control group was maximized at 10 days of incubation, and then decreased while the activity of phthalic acid treated group was increased. Glucose was used as a carbon source, and the difference of glucose consumption by control and phthalic acid treated group was not significant. However, after 6 days of incubation the residual glucose in culture medium was rapidly decreased. The consumption rate of phthalic acid treated group was lower than control. These results might indicate that the absorption of phthalic acid in culture medium was occurred by mycelium and metabolized through some pathways as that of glucose was. To clearify the chemical modification of phthalic acid in culture medium, phthalic acid was reacted under in vitro condition which mycelium was excluded. The metabolites were analyzed by GC/MS. The results showed that phthalic acid was converted to phthalic acid anhydride by the extracellular enzymes of P. brumalis.

• Microbiology and Biotechnology Letters
• /
• v.42 no.2
• /
• pp.99-105
• /
• 2014

A Bacillus strain capable of hydrolyzing locust bean gum was isolated as a producer of extracellular mannanase by way of an enrichment culture in an acidic medium from homemade soybean pastes. The isolate YB-1401 showed a biochemical identity of 61.1% with Brevibacillus laterosporus, while the nucleotide sequence of its 16S rDNA had the highest similarity with that of Bacillus amyloliquefaciens. The mannanase productivity of the Bacillus sp. YB-1401 was drastically increased by mannans. Particularly, maximum mannanase productivity was reached at approximately 265 U/ml in LB medium supplemented with konjac glucomannan (4.0%). The mannanase was the most active at $55^{\circ}C$ and pH 5.5. Mannanase activity was completely maintained after pre-incubation at pH 3.5 to 11.0 for 1 h. The predominant products resulting from the mannanase hydrolysis were mannobiose and mannotriose for LBG, guar gum or mannooligosaccharides. A small amount of mannose was also detected in the hydrolyzates.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.22 no.2
• /
• pp.240-245
• /
• 1993

The optimum pH and temperature for the purified extracellular enzyme activity were 8.0 and 37$^{\circ}C$, respectively. NaCl was required for the activation of the enzyme and optimum concentration was 0.5M. This enzyme activity was inhibited by HgC $l_2$, CoC $l_2$ and ZnC $l_2$ and stimulated by CaC $l_2$. The activity of enzyme was increased by L-cysteine and 2-mercaptoethanol, but decreased by ο-phenanthroline, $\rho$-CMB, EDTA and iodoacetate. The $K_{m}$ and $V_{max}$ values of extracellular enzyme appeared as 0.717% and 15.39U/mg, respectively.y.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.35 no.2
• /
• pp.231-237
• /
• 2006

The extracellular enzyme alginase produced by Bacillus licheniformis AL-577 was purified by ion chromatography on CM-Cellulose column, DEAE-Sepharose column, and followed by gel filtration on Sephadx G-100 column. The optimum pH and temperature for the activity of the purified enzyme were 6.0 and $35^{\circ}C$, respectively. The enzyme was stable at the pH range of $6.0\~9.0$ and at $20^{\circ}C$. The molecular weight of the enzyme was estimated to be about 25,500 daltons by SDS-polyacrylamide gel electrophoresis. NaCl was required for high activity of the enzyme. The enzyme was inhibited by $Ba^{2+},\;Co^{2+},\;Cu^{2+},\;Fe^{2+},\;Mg^{2+},\;Zn^{2+},\;NH_4^+$, EDTA, L-cysteine, and 2-mercaptoethanol, while stimulated by DTT, O-phenanthroline, $K^+$ and $Li^+$. This enzyme was proposed to be an alginase specifically degrading alginic acid.

• Journal of Life Science
• /
• v.26 no.10
• /
• pp.1113-1120
• /
• 2016

Two bacterial strains producing extracellular man nanase were isolated from doenjang, a traditionally fermented soybean paste in Korea. The isolates, WL-6 and WL-11, were identified as Bacillus subtiis on the basis of their 16S rRNA gene sequences, morphological, and biochemical properties. Two genes encoding the mannanase of both B. subtilis WL-6 and B. subtilis WL-11 were each cloned into Escherichia coli, and their nucleotide sequences were determined. Both mannanase genes consisted of 1,086 nucleotides, encoding polypeptides of 362 amino acid residues. The deduced amino acid sequences of the two WL-6 and WL-11 mannanases, designated Man6 and Man11, respectively, differed from each other by eight amino acid residues, and they were highly homologous to those of mannanases belonging to the glycosyl hydrolase family 26. The 26 amino acid stretch in the N-terminus of Man6 and Man11 was a predicted signal peptide. Both Man6 and Man11 were localized at the level of 94–95% in an intracellular fraction of recombinant E. coli cells. The enzymes hydrolyzed both locust bean gum and mannooligosaccharides, including mannotriose, mannotetraose, mannopentaose, and mannohexaose, forming mannobiose and mannotriose as predominant products. The optimal reaction conditions were 55°C and pH 6.0 for Man6, and 60°C and pH 5.5 for Man11. Man11 was more stable than Man6 at high temperatures.

• Microbiology and Biotechnology Letters
• /
• v.11 no.3
• /
• pp.205-210
• /
• 1983

Extracellular $\beta$-galactosidase was prepared from a culture of Lactobacillus sporogenes, a spore-forming lactic acid bacterium. The enzyme functioned optimally at pH 6.8 and at 6$0^{\circ}C$ o-nitrophenyl-$\beta$-D-galactopyranoside (ONPG) in 0.05M sodium phosphate buffer. The activation energy of the enzymatic hydrolysis of ONPG was about 16,000 cal/mole below $50^{\circ}C$ and 11,300 cal/mole above the temperature. It was fairly stable over a pH range from 4.0 to 8.0 losing only less than 30% of its activity after hearting at 6$0^{\circ}C$ and pH 6.8 for 3 hours. Metal ions showed no significant effect on the enzyme activity, whereas L-cysteine exerted a slight stimulatory effect at the concentration of 10mM. The km values were 1.48mM for ONPG and 64.5mM for lactose. Hydrolysis of ONPG by the enzyme was product-inhibited by galactose (Ki=13.3mM, competitive inhibition) and by glucose(Ki= 11.4mM, uncompetitive type). The enzyme activity was also noncompetitively inhibited in the presence of lactose (Ki= 17.8mM).