• Microbiology and Biotechnology Letters
• /
• v.28 no.1
• /
• pp.33-38
• /
• 2000

In order to produce ascorbic acid-2-phosphate from ascorbic acid, bacteria capable of transforming ascorbic acid to ascorbic acid-2-phosphate were isolated from soils and the stock cultures in our laboratory. Among them, a newly isolated bacterium LSH-3 having the best ability of producing ascorbic acid-2-phosphate was selected and partially identified as Pseudomonas sp. The optimum conditions for the production of ascorbic acid-2-phosphate from ascorbic acid and using its resting cells as the source os enzyme were investigated. The results were summarized as follows: The optimum cultivation time and the cell weight for the production of ascorbic acid-2-phosphate was 14 hours and 100g/I(wet weight), respectively. And 0.1%(v/v) Trition X-100 was the most effective surfactant. The optimum concentrations of ascorbic acid and pyrophosphate were 400mM and 500mM, respectively, which led to produce 14.54g/I of ascorbic acid-2-phosphate. The most effective buffer was 50mM sodium acetate. The optimum pH and temperature were 4.5 and $40^{\circ}C$, respectively. Under the above conditions, 17.71 g/I of ascorbic acid-2-phosphate was produced from ascorbic acid after 32 hour-incubation, which corresponded to 17.5% of conversion rate based on ascorbic acid.

• KSBB Journal
• /
• v.10 no.4
• /
• pp.370-373
• /
• 1995

The major by-products in ethanol fermentation by Saccharomyces cerevisiae were glycerol, acetaldehyde, acetic acid, lactic acid, and formic acid. The effects of these by-products on the cell growth and ethanol production were studied. By adding acetaldehyde or acetic acid in the fermentation broth, the cell growth decreased while the ethanol production increased. But glycerol and lactic acid had nearly no effects on the cell growth and the ethanol production. Acetic acid and acetaldehyde inhibited the cell growth by diminishing the growth rate as well as by prolonging the lag phase. The ethanol yield increased with the elevation of concentrations of acetic acid and acetaldehyde in the fermentation broth. The maximum ethanol yield was obtained for $3g/\ell$ acetic acid and $2g/\ell$ acetaldehyde, respectively.

• Microbiology and Biotechnology Letters
• /
• v.23 no.1
• /
• pp.6-11
• /
• 1995

In order to screen microorganism producing lactic acid with high productivity from nature, we used a medium containing 100 g/l glucose and selected several microorganisms producing more than 80 g/l L-lactic acid. We investigated their physiological characteristics and compared them. The best microorganism was identified as Lactobacillus casei subsp. rhamnosus. The optimum pH for growth and production of lactic acid was 6.0 and this strain showed the highest growth rate at around 30$\circ$C , but the optimum temperature for lactic acid production was 45$\circ$C . The growth was inhibited proportionally from 50 g/l to 300 g/l of glucose and the maximal cell mass increased according to increasing the concentration of corn steep liquor (CSL) protein up to 30 g/l. In batch fermentation for lactic acid production, we produced 128 g/l L-lactic acid with 20 g/l CSL protein and 150 g/l glucose in 35 hours. In pH-stat fed-batch fermentation, we were able to produce 183 g/l L-lactic acid.

• Current Research on Agriculture and Life Sciences
• /
• v.31 no.1
• /
• pp.25-29
• /
• 2013

As a specialty oil, furan fatty acids have gained special attentions since they are known to play important roles in biological systems including human. Although several studies reported chemical synthesis of furan fatty acids, their synthesis consisted of complicated chemical multistep with chemical catalysts. Recently, a simple one-step heat treatment method was developed to produce a novel furan fatty acid, 7,10-epoxy-octadeca-7,9-dienoic acid (7,10-EODA) from a dihydroxyl fatty acid 7,10-dihydroxy-8(E)-octadecenoic acid (DOD). In this report we studied about optimization of environmental conditions for the maximum production of 7,10-EODA from DOD by heat treatment. Production of 7,10-EODA was maximized at over $85^{\circ}C$ for at least over 48 hour in hexane. Solvent volume for maximum production should be over 300 mL per 10 mg DOD.

• Preventive Nutrition and Food Science
• /
• v.7 no.1
• /
• pp.37-42
• /
• 2002

Factors affecting the production of bacterial cellulose and organic acids in Kombucha fermentation were investigated. Kombucha was obtained by the fermentation (for 12 days at 3$0^{\circ}C$) of the green/black tea extract, supplemented with 10% white sugar, using an Oriental tea fungus as starter. Hitgher initial pH increased acid production with decreased cellulose production. With a cellulose pellicle or tea fungus broth as a starter, a 1~3 mm thick cellulose layer developed as a top layer every four days, and was removed subsequently while continuing fermentation. Addition of 30 mL tea fungus broth (13%, v/v) in Kombucha fermentation resulted in maximum production of a cellulose pellicle, indicating weak acid production. Yield of cellulose production at an early stage of fermentation was also higher when Kombucha was inoculated with a cellulose pellicle. In fact, addition of 1% (v/v) alcoholic beverage in the Kombucha fermentation activated the cellulose production, coupled with four times higher acid production.

• Journal of Microbiology and Biotechnology
• /
• v.18 no.3
• /
• pp.417-426
• /
• 2008

The effect of increasing levels of proclavaminate amidino hydrolase (Pah) on the rate of clavulanic acid production in Streptomyces clavuligerus ATCC 27064 was evaluated by increasing dosoge of a gene (pah2) encoding Pah. A strain (SMF5703) harboring a multicopy plasmid containing the pah2 gene showed significantly retarded cell growth and reduced clavulanic acid production, possibly attributable to the deleterious effects of the multicopy plasmid. In contrast, a strain (SMF5704) carrying a single additional copy of pah2 introduced into chromosome via an integrative plasmid showed enhanced production of clavulanic acid and increased levels of pah2 transcripts. Analysis of transcripts of other genes involved in the clavulanic acid biosynthetic pathway revealed a pattern similar to that seen in the parent. From these results, it appears that clavulanic acid production can be enhanced by duplication of pah2 through integration of a second copy of the gene into chromosome. However, increasing the copy number of only one gene, such as pah2, does not affect the expression of other pathway genes, and so only modest improvements in clavulanic acid production can be expected. Flux controlled by Pah did increase when the copy number of pah2 was doubled, suggesting that under these growth conditions, Pah levels may be a limiting factor regulating the rate of clavulanic acid biosynthesis in S. clavuligerus.

• Korean Journal of Food Science and Technology
• /
• v.22 no.2
• /
• pp.183-191
• /
• 1990

Soy milk prepared from soy protein concentrate was added with each of four types of milk products. Acid production and growth of five species of lactic acid bacteria(LAB) in soy milk and sensory property of soy yogurt were investigated. Acid production by LAB increased in proportion to concentration of milk products added to soy milk. Among the four milk products tested, whey powder or skim milk powder stimulated acid production by LAB more than whole milk powder or modified milk powder. Stimulating effect by whey powder on acid production by LAB was greater than other milk products at low concentration. Acid production by LAB in soy milk added with glucose or milk products significantly increased during fermentation. Sensory property of soy yogurt added with whole milk powder or skim milk powder was better than that of reference (soy yogurt added with glucose) while sensory property of soy yogurt added with whey powder or modified milk powder was Inferior to that of reference.

• Korean Journal of Food Science and Technology
• /
• v.19 no.2
• /
• pp.151-156
• /
• 1987

Four types of soy milk prepared from soybean, defatted soybean, soy protein concentrate (SPC) or soy protein isolate (SPI) were fermented with Lactobacillus acidophilus, L. bulgaricus, L. casei, Leuconostoc mesenteroides or Streptocroccus lactis. Growth and acid production by each organism in soy milks were investigated. Acid production by L. acidophilus was miximum in soy milk while acid production by other organisms was maximum in defatted soy milk. All the organisms produced least amount of acid in SPI-milk. Addition of yeast extract (0.5) to four types of soy milks stimulated acid production by lactic acid bacteria, particularly in case of L. acidophilus. Higher concentration of total solids in soy milks resulted in better growth and more acid production by L. acidophilus and L. bulgaricus.

• Asian-Australasian Journal of Animal Sciences
• /
• v.17 no.9
• /
• pp.1255-1259
• /
• 2004

The objective of this study was to evaluate the effects of halogenated compounds, organic acids, unsaturated fatty acids and their mixtures on in vitro methane production and fermentative characteristics of mixed rumen microorganisms. Agents used in two in vitro experiments were bromoethanesulfonic acid (BES) and pyromellitic diimide (PMDI) as halogenated compound, fumarate and malate as organic acid, and linoleic acid and linolenic acid as unsaturated fatty acid sources. Ruminal fluid collected from a Holstein steer fed tall fescue and concentrate mixtures was incubated at $39^{\circ}C$ for 48 h with addition of those materials. Single supplementation of halogenated compounds, organic acids or unsaturated fatty acids decreased in vitro methane production (p<0.05). The second experiment was designed to investigate effects of combination of one of halogenated compounds and either organic acids or fatty acids on methane production. Lower concentration of methane and lower A:P ratio were observed with PMDI compared with BES (p<0.01). In general medium pH, VFA, total gas and hydrogen production, and dry matter degradability were affected by addition of the same compounds. In addition, PMDI+malate treatment resulted in the highest molar proportion of propionate, and lowest A:P ratio and methane production (p<0.01). Hydrogen production was highest in PMDI+linolenic acid and lowest in BES+malate treatment (p<0.01). PMDI+malate combination was the most recommendable in reducing methane production without too much influence on digestibility under conditions of present studies.

• KSBB Journal
• /
• v.20 no.6
• /
• pp.447-452
• /
• 2005

The hydrogen production using immobilized cellsl was conducted using fruit wastewaters at various culture conditions. Three kinds of fruit wastewaters, melon, watermelon and pear were used. Sodium alginate was used as immobilization material. Among them, concentration of reducing sugar which was one of the main components in fruit was the highest at watermelon wastewater, and also hydrogen production was the highest as 2319.2 mL/L in it. Although hydrogen production was not much changed according to sodium alginate concentration, its production was the most at 3%(w/v). As bead size as small, hydrogen production was higher. With inspection of interior, it confirmed that the cell grew well in bead. But the addition of amino acids using as agent for metabolite production had almost no affected on hydrogen productivity. The effective range of $FeSO_4$ addition on hydrogen production were up to 1.2 g/L, and above the concentration, it inhibited the productivity. Organic acids produced during watermelon fermentation were mainly lactic acid, butyric acid, abd acetic acid; and a little of propionic acid.