• Journal of Microbiology and Biotechnology
• /
• v.5 no.4
• /
• pp.229-233
• /
• 1995

Acremonium chrysogenum was immobilized in ionotropic gel beads to develop semi-continuous production of cephalosporin C (CPC). Barium alginate beads were more stable than calcium alginate or strontium alginate beads in chemically defined media. The gel stability of Ba-alginate was further increased by cross-linking with polyethyleneimine (PEI). The presence of carboxymethyl cellulose inside Ba-alginate beads did not reduce mass transfer resistance. Ba-alginate microbeads that had little diffusion limitation increased CPC production rate 1.6 fold higher than that of normal beads. CPC fermentation with immobilized cells in Ba-alginate microbeads was performed continuously for 40 days by way of repeated fed-batch operations. Mathematical modeling was developed to describe the repeated fed-batch fermentation system. Results of the computer simulation agreed well with the experimental data, which made it possible to predict an optimal feeding rate that could maximize total CPC productions.

• Animal Bioscience
• /
• v.36 no.2_spc
• /
• pp.364-373
• /
• 2023

The gastrointestinal (GI) tract of ruminants contains diverse microbes that ferment various feeds ingested by animals to produce various fermentation products, such as volatile fatty acids. Fermentation products can affect animal performance, health, and well-being. Within the GI microbes, the ruminal microbes are highly diverse, greatly contribute to fermentation, and are the most important in ruminant nutrition. Although traditional cultivation methods provided knowledge of the metabolism of GI microbes, most of the GI microbes could not be cultured on standard culture media. By contrast, amplicon sequencing of 16S rRNA genes can be used to detect unculturable microbes. Using this approach, ruminant nutritionists and microbiologists have conducted a plethora of nutritional studies, many including dietary interventions, to improve fermentation efficiency and nutrient utilization, which has greatly expanded knowledge of the GI microbiota. This review addresses the GI content sampling method, 16S rRNA gene amplicon sequencing, and bioinformatics analysis and then discusses recent studies on the various factors, such as diet, breed, gender, animal performance, and heat stress, that influence the GI microbiota and thereby ruminant nutrition.

• Food Science and Biotechnology
• /
• v.17 no.5
• /
• pp.904-911
• /
• 2008

Covalent cross-links between a number of proteins and peptides explain why transglutaminase may be widely used by food processing industries. The objective of this work was optimization of the fermentation process to produce transglutaminase from a new microbial source, the Streptomyces sp. P20. The strategy adopted to modify the usual literature media was: (1) fractional factorial design (FFD) to elucidate the key medium ingredients, (2) central composite design (CCD) to optimise the concentration of the key components. Optimization of the medium resulted in not only an 86% increase in microbial transglutaminase activity as compared to the media cited in the literature, but also a reduction in the production cost. Optimal fermentation conditions - namely temperature and agitation rate - were also studied, using CCD methodology. Usual conditions of $30^{\circ}C$ and 100 rpm were within the optimal area. All other parameters for enzyme production were experimentally proven to be optimum fermentation conditions.

• Korean Journal of Microbiology
• /
• v.6 no.1
• /
• pp.12-21
• /
• 1968

The accelerate effects on the growth rate and the capacity of fermentation of L. delbrukii and B. subtilis was investigated in the Henneberg's medium added by various amounts of cellular components of Chlorella and Scenedesmus and also was investigated in the media added micronutritional elements such as Mn, Fe and Mo, etc. The results in the comparative experiments are as follow; 1. Various amounts of Chlorella cell components in the media accelerated remarkably the lactic acid formation and growth of L. delbrukii. For example, lactic acid formation in the medium of contained 1 percent Chlorella cell components was promoted more than twice effects compare with control. 2. The formation of .alpha.-amylase by B. subtilis in the medium of 2 percent Chlorella cell contents was also promoted more than nine twice effects compare with control. 3. The formation of lactic acid of L. delbruckii in the medium of Scenedesmus cell contents was a little more than in the medium of Chlorella cell contents. 4. The lactic acid fermented level attained with the addition of 0.2-0.25 percent Chlorella cells was the effect of promoting fermentation attained of saturating level at 100$\mu$g. /ml. of Mn and 0. 1 $\mu$g./ml. of Fe.

• Journal of Life Science
• /
• v.21 no.9
• /
• pp.1315-1322
• /
• 2011

This study was conducted to investigate the effects of several herbal extracts (obtusifolia, cinnamon, chinese pepper, licorice root) on the characteristics of rumen fermentation in vitro. Soybean meal was used as a substrate for fermentation in vitro. Herbal extracts were supplemented to media by 10% of the substrate. The substrates supplemented to Dehority artificial media with herbal extracts were fermented in 30ml serum bottles for 0, 3, 6, 9, 12 and 24 hr at $39^{\circ}C$. Cumulative gas production was significantly (p<0.05) greater in the herbal extract supplements than in the control, in the order of licorice root, chinese pepper, cinnamon and obtusifolia. Methane proportions of the herbal extracts were significantly (p<0.05) higher than that of the control. Licorice root extract supplementation resulted in the lowest methane proportion at 3 hr fermentation. Proportion of hydrogen was significantly (p<0.05) higher in the herbal extract supplements than in the control at 12 hr fermentation. Compared to the control, ammonia concentration in the licorice root was significantly higher at 3 hr fermentation, but lower at 12 hr fermentation (p<0.05). Based on these results, supplementation of the herbal extracts used in this experiment resulted in increased cumulative gas production and stimulating methane production in vitro rumen fermentation.

• Microbiology and Biotechnology Letters
• /
• v.21 no.6
• /
• pp.615-621
• /
• 1993

In order to maximize the riboflavin production by a mutant strain Ashbya gosspyii, the optimization of medium and fed-batch fermentation were performed. As carbon sources, glucose and soybean oil were necessary for the riboflavin overproduction. Optimal concentrations of glucose and soybean oil in the flask cultures were found to be 3.0% and 0.5%, respectively, in a complex medium containing corn steep liquor(CLS) 1%. Among the various organic nitrogen sources tested, CSL was the most effective one both for the cell growth and riboflavin overproduction.

• Journal of Microbiology and Biotechnology
• /
• v.2 no.3
• /
• pp.226-229
• /
• 1992

An ethanol tolerant mutant was selected by successive transfers of Clostridium thermohydrosulfuricum ATCC 33223 into the media with progressively higher ethanol concentrations. The growth kinetics of the mutant were characterized under various growth conditions. Physiological differences such as enhanced growth, tolerance to various solvents, alteration of the optimum temperature and the ratio of end products during fermentation were noticed in the mutant.

• Korean Journal of Food Science and Technology
• /
• v.5 no.4
• /
• pp.224-230
• /
• 1973

The culture used wheat bran as media for four kind of mold strains such as Aspergillus oryzae, Aspergillus kawachii, Aspergillus usamii and Rhizopus javanicus to examine which strain could higher the activity of amylase most which is used for alcohol fermentation. It also provided three different kind of wheat bran media containing starch of 47%, 51% and 55% respectively for each strain. For each media it also added three different kind of nitrogen sources; ammonium sulfate, casein, and ammonium sulfate and casein equally mixed. Each nitrogen source added was subordinately differentiated into three different percentages, 2%, 4% and 6% respectively, except the 2% for the ammonium sulfate. The results obtained were summarized as follows (1) The activity of ${\alpha}-amylase$ was highest in the media of starch value 47% of wheat bran with 6% of casein added. (2) The activity of ${\beta}-amylase$ was highest in the media of starch value 51% of wheat bran with 2% of the equal mixture of ammonium sulfate and casein added. (3) The activities of both ${\alpha}-amylase$ and ${\beta}-amylase$ of Aspergillus usamii were highest in the media of starch value 47% wheat bran with no addition of nitrogen source. (4) Of the four strains examined, the activities of ${\alpha}-amylase$ and ${\beta}-amylase$ cultured in Rhizopus javanicus were both relatively higher. (5) The activities of ${\alpha}-amylase$ and ${\beta}-amylase$ of the strains examined became lower as the percentage of starch contents increased except in Rhizopus javanicus.

• Microbiology and Biotechnology Letters
• /
• v.14 no.2
• /
• pp.193-198
• /
• 1986

Improvement of productivity in ethanol fermentation was attempted using a hollow fiber bioreactor (HFR) where Saccharomyces cerevisiac var. ellipsoideus cells were recycled to achieve a high yeast concentration. Industrial wort was used as the fermentation media without supplying any additional nutrients. The performances in hollow fiber recycle reactor (HFR) were compared with those of batch and continuous cultures. In a continuous culture with 11$^{\circ}$P and 15$^{\circ}$P wort media final ethanol concentrations were 4.71% and 5.82% (v/v) and yields 86.2% and 78.6% respectively when the dilution rate (D) was 0.1 h$^{-1}$, in contrast, the ethanol concentration and productivity in HFR were 7.64%(v/v) and 6.1g/l/h at D=0.1h$^{-1}$ with 15$^{\circ}$P media. When the dilution rate was increased to 0.2 h$^{-1}$, the concentration and the Productivity were 7.62% (v/v) and 12.2g/l/h. At D=0.3h$^{-1}$ the sugar was completely consumed and the productivity was 18.1g/l/h. This correponds to 4 times that in continuous system and 16.3 times that in the batch system performed in comparable conditions.

• Journal of Food Hygiene and Safety
• /
• v.31 no.1
• /
• pp.36-41
• /
• 2016

Ochratoxin A and aflatoxin may be detected from naturally fermented foods due to the contamination of the mycotoxin-producing molds or un-prudential use of the mycotoxin producing starter strains during the fermentation. This study was carried out to analyze the production of ochratoxin A and aflatoxin under the various environmental conditions. For the experiment, the effects of different temperature, culture media, and fermentation time on the production of ochratoxin A by Aspergillus usamii KFRI 999 and A. awamori KFRI 983 were analyzed. Additionally, the production of aflatoxin was assessed under the various temperature, initial pH, fermentation time and culture media during fermentation by A. flavus KACC 41403 and A. oryzae KACC 46471. The levels of ochratoxin A and aflatoxin were analyzed by HPLC. The result showed that the production of mycotoxin was greatly affected by the fermentation temperature. A. oryzae KACC 46471 did not produce aflatoxin. All of the mycotoxin producing strains showed the highest level of mycotoxin at $30^{\circ}C$. A. awamori KFRI 983 showed the lowest level of ochratoxin A in PDA media among the experimental medium. The results of the present study may be useful for the reduction of ochratoxin A and aflatoxin in various foods.