• Microbiology and Biotechnology Letters
• /
• v.15 no.2
• /
• pp.112-115
• /
• 1987

Optimal pH temperature and sucrose content for the production of vitamin B$_{12}$ and riboflavin by Bacillus megaterium and Enterobacter aerogenes was studied by microbiological analysis. Optimal pH for the production of B$_{12}$ was 6.0 by B. megaterium while the pH for E. aerogenes was 5.0. However, upon the addition of sucrose the optimal pH for B. megaterium shifted to 7.5 but E. aerogenes remained at pH 5.0. In the absence of sucrose, pH did not influence the yields of riboflavin produced by either bacterium. Addition of sucrose stimulated synthesis of riboflavin by both bacteria. Temperature had little effect on the production of vitamins by either bacterium.

• 한국생물공학회:학술대회논문집
• /
• 2001.11a
• /
• pp.525-528
• /
• 2001

The purpose of this study is to looking for the optimal condition of methane production enhancement. The conditions tested for increasing methane production were temperature. pH. and various carbon sources including methanol. formic acid. sodium acetate. succinic acid. and glucose. As a result, optimal temperature was 55 .C and optimal pH was around neutral condition. And methanol seemed to be best carbon source which can drastically increase methane production.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.26 no.4
• /
• pp.620-624
• /
• 1997

The conditions for color intensity and electron donating ability to $\alpha$,$\alpha$-diphenyl-$\beta$- picryl-hydrazyl (DPPH) of Bacillus subtilis DC-2 were investigated. Temperature, pH and cultivation time were chosen as three factors, and the optimal conditions of color intensity and DPPH was determined with response surface methodology. Color intensity was affected by cultivation temperature(p<0.1). DPPH was influenced by cultivation temperature(p<0.05) and pH(p<0.1). But cultivation time was affected neither color in- tensity nor DPPH. Optimal conditions of color intensity with Bacillus subtilis DC-2 were appeared at cultivation temperature of 39.$25^{\circ}C$, pH 8.83 and cultivation time of 84.41hrs. Optimal conditions of DPPH with Bacillus subtilis DC-2 were revealed at cultivation temperature of 39.19$^{\circ}C$, pH 8.84 and cultivation time of 82.21hrs.

• Journal of Microbiology and Biotechnology
• /
• v.16 no.12
• /
• pp.1856-1861
• /
• 2006

A Bacillus sp. A-6 strain that produced xylanase was isolated from rice bran. The optimal temperature and pH for xylanase activity of the culture supernatant of Bacillus sp. A-6 were 40$^{\circ}C$ and pH 7, respectively. The optimal temperature and pH for xylanase production in the xylan medium were 30$^{\circ}C$ and pH 9, respectively. The optimal concentrations of oat spelt xylan and peptone for xylanase production were 0.5% and 1.5%, respectively. The best nitrogen sources for xylanase production was beef extract, but xylanase production was also supported comparably by tryptone and peptone. The bacterial growth in the optimal xylan medium reached stationary growth phase after 12 h of incubation. The xylanase production in the culture supernatant increased dramatically during the initial 12 h exponential growth phase and then remained constant at 23.8-24.5 unit/ml during the stationary growth phase. The pH of the culture medium decreased from 8.8 to 6.7 during the exponential growth phase and subsequently increased to 8.1 during the stationary growth phase. Rice bran, sorghum bran, and wheat bran as well as oat spelt xylan induced xylanase production. The xylanase production was repressed when glucose was added to the xylan-containing medium.

• Microbiology and Biotechnology Letters
• /
• v.23 no.3
• /
• pp.304-310
• /
• 1995

A thermophilic bacterium producing the extracellular cellulase-free xylanase was isolated from soil and has been identified as Bacillus sp. The optimal growth temperature was 50$\circ$C and the optimal pH, 7.0. Under the optimal growth condition, maximal xylanase production was 2.2 units/ml in the flask culture. The enzyme production was induced by xylan and xylose, but was repressed by sucrose or trehalose. The partially purified xylanase was most active at 70$\circ$C. It was found that the enzyme was stable at 65$\circ$C for 10 hours with over 75% of the activity. The enzyme was most active at pH 7.0 and retained 90% of its maximum activity between pH 5.0 and pH 9.0 though Bacillus sp. was not grown on alkaline conditions (>pH 8.0). In addition, the activity of xylanase was over 60% at pH 10.0. At the ambient temperature, the enzyme was stable over a pH range of 5.0 to 9.0 for 10 h, indicating that the enzyme is thermostable and alkalotolerant. The activity of xylanase was completely inhibited by metal ions including Hg$^{2+}$ and Fe$^{2+}$, while EDTA, phenylmethylsulfonyl fluoride (PMSF), $\beta$-mercaptoethanol and SDS didn't affect its activity. The enzyme was also identified to exert no activity on carboxymethylcellulose, laminarin, galactomannan, and soluble starch.

• Biotechnology and Bioprocess Engineering:BBE
• /
• v.9 no.4
• /
• pp.297-302
• /
• 2004

A chitinase-producing bacterium was isolated from seashore mud around Beobseongpo in Chunmam province through the use of a selective enrichment culture. The best chitinase producing strain was isolated and identified as Serratia marcescens KY from its characteristics. For effective production of chitinase, optimum pH, temperature, and agitation speed were investigated in flask cultures. The optimum pH using Serratia marcescens KY was between pH 6 and 7 and the chitinase produced was 37.9 unit/mL. On the other hand, the optimal pH of the Serratia marcescens ATCC 27117 was 7.5, and the produced amount of chitinase was 35.2 unit/mL. The optimal temperature for chitinase production for Serratia marcescens KY and Serratia marcescens ATCC 27117 was $30^{\circ}$. The cell growth pattern at different temperature was almost identical to the chitinase production. To investigate the optimal shaking speed under optimal culture, speeds were varied in the range of 0∼300 rpm. The maximum production of chitinase was carried at 200 rpm although the cell growth was the highest at 150 rpm. It indicates that oxygen adjustment is required for the maximum chitinase production. Using optimal conditions, batch cultures for comparing Serratia marcescens KY and Serratia marcescens ATCC 27117 were carried out in a 5 L fermentor. The oxygen consumption was increased with the increase of culture. Especially, at 120 h of culture Serratia marcescens KY and Serratia marcescens ATCC 27117 produced 38.3 unit/mL, and 33.5 unit/mL, respectively.

• Journal of Korean Society of Water and Wastewater
• /
• v.28 no.5
• /
• pp.601-608
• /
• 2014

A coagulation-flocculation (CF) process using aluminum sulfate as a coagulant was employed to treat highly suspended solids in tunnel wastewater. Response surface methodology (RSM) based on a Box-Behnken design was applied to evaluate the effects of three factors (coagulant dosage, pH and temperature) on total suspended solids (TSS) removal efficiency as well as to identify optimal values of those factors to maximize removal of TSS. Optimal conditions of coagulant dosage and pH for maximum TSS removal changed depending on the temperature ($4{\sim}24^{\circ}C$). As temperature increased, the amount of coagulant dosage and pH level decreased for maximum TSS removal efficiency during the CF process. Proper adjustment of optimal pH and coagulant dosage to accommodate temperature fluctuations can improve TSS removal performance of the CF process.

• Journal of Life Science
• /
• v.13 no.4
• /
• pp.498-504
• /
• 2003

This Study was carried out to investigate the optimal mycelial growth of Pholiota nameko. The optimal medium for the mycelial growth was ME medium. The optimal temperature and pH were $25^{\circ}C$$\pm$1 and 5.5, respectively. The modified optimal medium compositions were glucose 3% (w/v), malt extract 0.25% (w/v), yeast extract 0.25% (w/v), $KH_2PO_4$ 0.046% (w/v), $K_2HPO_4$ 0.1% (w/v), $MgSO_4$ㆍ$7H_2O$ 0.05% (w/v). From the result of experiments on the optimal temperature, pH and nutritional requirements, the mycelial growth of modified optimal medium was higher than that of ME medium.

• Journal of Life Science
• /
• v.6 no.2
• /
• pp.79-86
• /
• 1996

A bacterium producing pullulanase was from soil, and was identified Bacillus cereus and named as Bacillus cereus JK36. The optimal culture conditions for the efficident production of pullulanase from B. cereus JK36 was obtained by cultivating with the medium composed of 1% pullulan, 1% teast extract, 1% bactopeptone, 0.1% NaH$_{2}$PO$_{4}$, 2H$_{2}$O, 0.02% MgSO$_{4}$\ulcorner7H$_{2}$O at 40$\circ$C, initial pH 6.5 for 70 hours. Using the culture supernatant as crude enzyme, the optimal pH and temperature of the pullulanase of this strain were 6.5 and 50$\circ$C. In effect of pH and temperature on the stability of the enzyme, the enzyme was stable in the range of pH6.0$\sim$9.5 and up to 40$\circ$C, respectively. The hydrolysis product on pullulan was mainly maltotriose.

• Journal of Surface Science and Engineering
• /
• v.25 no.4
• /
• pp.189-206
• /
• 1992

The effect of activation and electroless nickel plating conditions on contact properties was investi-gated for selective electroless nickel plating of Si wafers in order to obtain an optimum condition of con-tact hole filling. According to RCA prosess, p-type silicon (100) surface was cleaned out and activated. The effects of temperature, DMAB concentration, time, and strirring were investigated for activation of p-type Si(100) surface. The optimal activation condition was 0.2M HF, 1mM PdCl2, 2mM EDTA,$ 70^{\circ}C$, and 90sec under ultrasonic vibration. In electroless nickel plating, the effect of temperature, DMAB concentra-tion, pH, and plating time were studied. The optimal plating condition found was 0.10M NiSO4.H2O, 0.11M Citrate, pH 6.8, $60^{\circ}C$, 30minutes. The contact resistance of films was comparatively low. It took 30minutes to obtain 1$\mu\textrm{m}$ thick film with 8mM DMAB concentration. The film surface roughness was improved with decreasing temperature and decreasing pH of the plating solution. The best quality of the film was obtained at the condition of temperature $60^{\circ}C$ and pH 6.0. The micro-vickers hardness of film was about 800Hv. Plating rate of nickel on the hole pattern was slower than that of nickel on the line pattern.