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PubMed2000

Effect of administration of fermented milk containing whey protein concentrate to rats and healthy men on serum lipids and blood pressure.

The effect of fermented milk supplemented with whey protein concentrate on the serum lipid level of rats was investigated. The serum total cholesterol level for the group fed fermented milk with both Lactobacillus casei TMC0409 and Streptococcus thermophilus TMC 1543 was significantly lower than that of the control group (P<0.05) in rats. Furthermore, the effect of the longterm intake of this fermented milk on the serum lipid level of twenty healthy adult men was investigated. During the 8-wk study, the volunteers consumed 200 ml of fermented milk or placebo in the morning and evening. Blood samples were drawn for analysis three times, just before taking the experimental diet, and after 4 wk and 8 wk of consumption. After 8 wk, the high density lipoprotein cholesterol level for the fermented milk group showed a significant rise after 4 wk (P<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The triglyceride level for the fermented milk group lowered significantly after 4 wk (<0.05), whereas that of the placebo group showed no change even after 4 wk (P>0.05). The atherogenic index [(total cholesterol - high density lipoprotein cholesterol)/high-density lipoprotein cholesterol] for the fermented milk group decreased significantly from 4.24 to 3.52 (P<0.05). The systolic blood pressure lowered significantly by the intake of fermented milk (P<0.05) On the other hand, such effect was not observed in the placebo group (P>0.05). These results indicate potential of the development of fermented milk with multiple therapeutic effects.

Adult↗
PubMed1997

Relationship between fermentation acid production in the rumen and the requirement for physically effective fiber.

The content of ruminally fermented OM in the diet affects the fiber requirement of dairy cattle. Physically effective fiber is the fraction of feed that stimulates chewing activity. Chewing, in turn, stimulates saliva secretion. Bicarbonate and phosphate buffers in saliva neutralize acids produced by fermentation of OM in the rumen. The balance between the production of fermentation acid and buffer secretion is a major determinant of ruminal pH. Low ruminal pH may decrease DMI, fiber digestibility, and microbial yield and thus decrease milk production and increase feed costs. Diets should be formulated to maintain adequate mean ruminal pH, and variation in ruminal pH should be minimized by feeding management. The fraction of OM that is fermented in the rumen varies greatly among diets. This variation affects the amount of fermentation acids produced and directly affects the amount of physically effective fiber that is required to maintain adequate ruminal pH. Acid production in the rumen is due primarily to fermentation of carbohydrates, which represent over 65% of the DM in diets of dairy cows and have the most variable ruminal degradation across diets. The non-fiber carbohydrate content of the diet is often used as a proxy for ruminal fermentability, but this measure is inadequate. Ruminal fermentation of both nonfiber carbohydrate and fiber is extremely variable, and this variability is not related to the nonfiber carbohydrate content of the diet. The interaction of ruminally fermented carbohydrate and physically effective fiber must be considered when diets for dairy cattle are evaluated and formulated.

Animals↗
PubMed2004

[A preliminary report on solid-state fermentation of Ganoderma lucidum with Radix Astragali containing medium].

OBJECTIVE: To test the practicability of the solid-state fermentation for medicinal fungi by fermenting Ganoderma lucidum with Radix Astragali containing medium. METHODS: Ganoderma lucidum was fermented in ordinary medium, drug-containing medium (containing Radix Astragali) and selenium-rich drug-containing medium respectively. The polysaccharide contents of fermentation products from the three kinds of culture media were tested at different time, and the changes were compared. RESULTS: The polysaccharide contents of fermentation products from the three kinds of culture media were 4.65%, 3.76% and 4.50% respectively and their relative standard deviation were 1.61%, 1.99% and 1.86% respectively. By observing the changes of the contents of polysaccharide, protein and total saponin in fermentation products from the drug-containing medium at different time, it was found that the 28th fermentation day was the time when secondary metabolism was most active, and it should be the fermented terminal point. CONCLUSION: The fermentative combination of Ganoderma lucidum and Radix Astragali is practicable.

Astragalus propinquus↗
PubMed2000

Effect of pH on survival, thermotolerance, and verotoxin production of Escherichia coli O157:H7 during simulated fermentation and storage.

Heat treatment is increasingly being introduced to fermented meat processing, since the acid tolerance properties of Escherichia coli O157:H7 can permit this organism to survive traditional processing procedures. This study investigated the effect of growth pH and fermentation on the thermotolerance at 55 degrees C of E. coli O157:H7 in a model fermented meat system. E. coli O157:H7 (strain 380-94) was grown at pH 5.6 or 7.4 (18 h at 37 degrees C), fermented to pH 4.8 or 4.4 in brain heart infusion broth, and stored for 96 h. Cells grown at pH 5.6 had higher D values at 55 degrees C (D55 degrees C) than cells grown at pH 7.4 (P < 0.001). Cells fermented to pH 4.8 had higher D55 degrees C than those fermented to pH 4.4 (P < 0.001). Cells fermented to pH 4.8 demonstrated an increase in D55 degrees C during storage (P < 0.001), whereas cells fermented to pH 4.4 showed a decrease in D55 degrees C during the same period (P < 0.001). The effect of growth pH on verotoxin production by E. coli O157:H7 was assessed using the verotoxin assay. Cells grown at pH 5.6 had lower verotoxin production then cells grown at pH 7.4. This effect was not sustained over storage. These results indicate that a lower growth pH can confer cross-protection against heat. This has implications for the production of acidic foods, such as fermented meat, during which a heating step may be used to improve product safety.

Animals↗
PubMed2001

Radioprotective effects of miso (fermented soy bean paste) against radiation in B6C3F1 mice: increased small intestinal crypt survival, crypt lengths and prolongation of average time to death.

The radioprotective effect of miso, a fermentation product from soy bean, was investigated with reference to the survival time, crypt survival and jejunum crypt length in male B6C3F1 mice. Miso at three different fermentation stages (early-, medium- and long-term fermented miso) was mixed in MF diet into biscuits at 10% and was administered from 1 week before irradiation. Animal survival in the long-term fermented miso group was significantly prolonged as compared with the short-term fermented miso and MF cases after 8 Gy of 60Co-gamma-ray irradiation at a dose rate of 2Gy min(-1). Delay in mortality was evident in all three miso groups, with significantly increased survival. At doses of 10 and 12 Gy X-irradiation at a dose rate of 4 Gy min(-1), the treatment with long-term fermented miso significantly increased crypt survival. Also the protective influence against irradiation in terms of crypt lengths in the long-term fermented miso group was significantly greater than in the short-term or medium-term fermented miso and MF diet groups. Thus, prolonged fermentation appears to be very important for protection against radiation effects.

Animals↗
PubMed2002

[The solid-state fermentation with double dynamic of gas phase for celluloses].

To utilize the advantages of solid-state fermentation for cellulose production, the solid-state fermentation with double dynamic of gas phase was proposed. The studies showed as follows: under the optimum operating conditions, the air pulsation range, the air pulsation periods and the air internal circulation, the fermentation temperatures were controlled quite well and the maximum temperature difference was 0.12 degree C/cm at a bed height of 9.0 cm; the water activity in the fermentation with steam-exploded straw as substrate was very suitable for the fungal growth; and with the observation of microbial growth by ESEM. It was discovered that air-pulsating fermentation was more advantageous to cellulose production and microorganism growth than static fermentation. The period of air-pulsating fermentation (60 h) was almost shorter 1/3 and its filter paper activity of enzymes (20.36 IU/mg) was larger 1 time than in the static fermentation with the fermentation period 84 h and the enzyme activity (10.82 IU/mg). Thus, this double dynamic of gas laid strong basis for cellulose production on a large scale.

Air↗
PubMed2005

[Fermented wheat germ extract in the supportive therapy of colorectal cancer].

The role of the product in the treatment of colorectal cancer is reviewed in the light of experimental and clinical results to date. The fermented wheat germ extract (code name: MSC, trade name: Avemar) registered as a dietary food for special medical purposes for cancer patients to complement the active oncotherapy, exerted a growth inhibitory effect in HCR-25 human colon carcinoma xenograft, and had a synergistic effect with 5-FU in mouse C-38 colorectal carcinoma. The product is capable of chemoprevention of colon carcinoma in F-344 rats. One of the most significant underlying mechanism is a highly cancer cell specific induction of caspase-3 mediated cleavage of PARP. In the frame of supportive therapy, fermented wheat germ extract proved to be efficient in the treatment of colorectal cancer in humans. 30 patients following radical operation were treated with standard postoperative therapy, 12 of them were given fermented wheat germ extract as additive treatment: following a 9 month long administration, no new distant metastases were detected, in contrast to 4 out 18 treated with standard therapy alone. Out of 34 patients following radical surgery and treated with chemotherapy, 17 who were given fermented wheat germ extract, achieved an improved survival rate. In the frame of a controlled multicenter open label cohort study, 170 colorectal cancer patients received anticancer therapies (chemo/radiotherapy) completed with fermented wheat germ extract in 66 of them. Results (fermented wheat germ extract vs. control): new recurrences: 3.0% vs. 17.3% (p < 0.01); new metastases: 7.6% vs. 23.1% (p < 0.01); deaths: 12.1% vs. 31.7% (p < 0.01), progression-related events in total: 16.7% vs. 42.3% (p < 0.001). Survival analysis showed significant improvements in the fermented wheat germ extract group, regarding progression-free (p = 0.0184) and overall survival probabilities (p = 0.0278). Strong predictors of survival determined by Cox's proportional hazards were UICC stage and fermented wheat germ extract treatment. Mild gastrointestinal side effects were observed in 9 cases. Supportive application of fermented wheat germ extract in colorectal cancer is highly recommended.

Adult↗
PubMed2006

Lactic acid fermentation stimulated iron absorption by Caco-2 cells is associated with increased soluble iron content in carrot juice.

An in vitro digestion/Caco-2 cell model was applied to explore the impact of lactic acid (LA) fermentation by Lactobacillus pentosus FSC1 and Leuconostoc mesenteroides FSC2 on the Fe bioavailability of carrot juice. The redox state of Fe in fermented carrot juice was also assessed as a crucial factor for absorption. LA fermentation was shown to improve mineral solubility to different extents at simulated physiological conditions: Mn (2-fold); Fe (1.5-1.7-fold); Zn (1.2-fold); Cu (1-fold). Soluble Fe2+ was increased about 16-fold by LA fermentation, and about one third of the Fe2+ remained soluble after in vitro digestion (about 4-5-fold higher than in fresh juice). Data on cell-line studies showed a 4-fold increase in the efficiency of Fe uptake, but not in transepithelial transfer by Caco2 cells, as a result of fermentation. The increases in Fe2+ level and the efficiency of cellular Fe uptake were strain-dependent. To sum up the effect on both Fe solubility and cellular uptake efficiency, the amount of cellularly absorbed Fe from Ln. mesenteroides FSC2-fermented juice was about 20 % higher than that from L. pentosus FSC1-fermented juice (22.7 v. 19.2 microg/l juice per mg protein). To conclude, LA fermentation enhanced Fe absorption by Caco-2 cells from carrot juice because of increases in not only Fe solubility after digestion, but also the efficiency of cellular Fe uptake. The fermentation-improved efficiency of Fe uptake was possibly due to the increased level of soluble Fe2+ rather than a being a strain-specific event.

Beverages↗
PubMed1994

Intestinal transport and fermentation of resistant starch evaluated by the hydrogen breath test.

OBJECTIVE: To study fermentability of different samples of resistant starch (RS), compared to one another and to lactulose, and to study the effect on gastric emptying of addition of RS to test meal. Finally to study if adaptation to RS results in a measurable change in fermentation pattern, (H2/CH4 production). Sources of RS: Raw potato starch (RPS), 58% RS; corn flakes (CF), 5% RS; hylon VII high amylomaize starch, extrusion cooked and cooled (HAS) 30% RS; highly retrograded hylon VII high amylomaize starch (HRA) 89% RS. DESIGN: (1) Fermentation: seven healthy volunteers ingested in randomized order 50 g RPS, 100 g CF, 75 g HAS, 25 g HRA. End-expiratory H2/CH4 was measured every 30 min for 12 to 22 hours post-ingestion as a measure of fermentation. A dose-response study of RPS, 5, 10, 25, 50, 75 and 100 g was performed. (2) Adaptation: In five 3-week periods seven volunteers added daily to their usual diet 50 g of either RPS, HAS, oat bran, wheat bran or common maize starch. The polysaccharides were administered in randomized order. The test periods were separated by 1 week's wash out. Basic end-expiratory H2/CH4 was measured once a week prior to and during the test periods. (3) Gastric emptying: The rate of increase in blood glucose was measured after test meals consisting of 50 and 100 g of RPS, 50 g HAS and 50 g glucose dissolved in a gel, alone, and mixed with 25 g of RPS. As controls we chose wheat bran and oat bran. RESULTS: (1) We found that RPS is fermentable, although the cumulated excessive H2 production after 50 g RPS corresponding to 29 g RS was clearly less than after 10 g lactulose. The time from ingestion of RPS to a sustained increase in end-expiratory H2 (apparent transit time; 5-11 h) was longer than lactulose (1-4 h), indicating either a slow passage through the small intestine or a slow fermentation rate. 100 g of corn flakes (4.6 g RS) resulted in a measurable increase in H2 production, equivalent to 10-20 g RPS, whereas neither of the two samples of hylon VII high amylomaize resulted in any significant increase in H2 production. The dose-response study with RPS showed that even 5 g of RPS resulted in a measurable increase in end-expiratory H2, and increasing doses from 5 g to 100 g resulted in a seemingly exponential increase in H2 production. (2) 3 weeks' daily administration of HAS resulted in a slightly elevated increase in basic end-expiratory H2, although the increase did not reach statistical significance. RPS resulted in a sustained increase in basic end-expiratory H2. Both RS samples increased measurable end-expiratory CH4 in volunteers with measurable CH4 production after a lactulose load, but 3 weeks' daily challenge with these slowly fermentable substrates did not increase measurable CH4 in volunteers, who prior to the study only produced CH4 intermittently. (3) The rate of increase in blood sugar was unaffected by addition of RS or non-starch-polysaccharides to the test meal, indicating that addition of the polysaccharides does not affect gastric emptying. CONCLUSIONS: A fraction of RPS is resistant to digestion in the small intestine, and it is fermentable by the colonic microbial flora. RS from CF, HAS and RPS give very different H2 responses, either due to differences in digestion patterns or fermentation patterns. Short-term adaptation (3 weeks) to HAS or RPS does not change the H2/CH4 response. RS does not affect gastric emptying of a test meal consisting of glucose dissolved in a gel.

Adaptation, Physiological↗
PubMed2002

Novel epidemiologic evidence for the association between fermented fish sauce and esophageal cancer in South China.

Previous studies have suggested that fermented fish sauce is related to an increased risk for nasopharyngeal, thyroid and gastric cancers and has suspicious carcinogenic and promoting effects in the laboratory, but these reports have not investigated the association between this agent and esophageal cancer in population. Therefore, we investigated the relationship between esophageal cancer and consumption of fermented fish sauce, alcohol and tobacco after adjusting other risk factors using data from a large hospital-based case-control study in Chaoshan area of China. The subjects for analysis included 1,248 cases (median age 58.5 [range 29-82] years, 936 males, 312 females, some 50% with the habit of fermented fish sauce eating) with squamous cell carcinoma of the esophagus and the same amount of controls matched by sex and age. A significant increase in risk (OR 3.21; 95% CI 2.45-4.19) for eating fermented fish sauce compared to not eating and a significant dose-response relationship was found with the consumption of fermented fish sauce (p for trend < 0.001). In comparison based on the binary variables, the OR for the subjects with fermented fish sauce eating and current smoking was 15.5 with a 95% CI of 8.14-29.3, relative to those exposed to neither habit. The joint effect of fermented fish sauce (F) and smoking (S) was more than additive (F * S > F + S: 15.5 > 1 + (5.6 - 1) + (6.6 - 1)), but the effect for fermented fish sauce and alcohol was not found. It is concluded that risks of esophageal cancer in the population were substantially associated with fermented fish sauce. Further epidemiologic and experimental study are required to find a biologic causal relationship between them.

Adult↗
PubMed2003

Impact of oxygen addition during enological fermentation on sterol contents in yeast lees and their reactivity towards oxygen.

During enological fermentations, superfluous oxygen consumption by yeast cells is observed. The superfluous oxygen consumed by the yeast cells is mainly related to the operation of non-respiratory oxygen consumption pathways resulting in an overall decrease in the total sterol fraction in yeast. On the other hand, yeast lees remaining at the end of alcoholic fermentations exhibit specific oxygen utilization rates ranging from 1 to 4 micromol O2 h- 10(-10) cells from the second to the thirteenth month of wine aging. This oxygen consumption capacity of yeast lees was independent of residual cell viability. In this study, we investigated the potential relationship between the oxygen added to commercial yeast strains during enological fermentation and the capacity of the corresponding yeast lees to interact with oxygen. Additions of low (7 mg l(-)) and excess (37 mg l(-1)) amounts of oxygen at the end of the cell growth phase were compared in terms of repercussions on the oxygen consumption activity of the corresponding yeast lees. As expected, the superfluous oxygen consumption by yeast cells during fermentation had a positive influence on the fermentation kinetics and increased cell biomass formation. Oxygen consumption rates and the total capacity of oxygen consumption by the corresponding yeast lees clearly decreased when oxygen was added during fermentation. This marked decrease in yeast lees reactivity towards oxygen was concomitantly related to an increase in ergosterol synthesis and to oxygen-dependent sterol degradation. Such degradation occurred when oxygen was added in excess. Therefore, oxygenation control during fermentation appears to be a potential way to optimize both the fermentation kinetics and control yeast lees reactivity towards oxygen. For practical applications, oxygenation control during alcoholic fermentation may be considered as a general tool for decreasing the highly reductive effect of yeast lees during wine aging.

Journal Article↗
PubMed2004

Effects of indigenous starter cultures on the microbial and physicochemical characteristics of Urutan, a Balinese fermented sausage.

Urutan is a Balinese traditional dry fermented sausage prepared from lean pork and various kinds of spice. Urutan is different from the European sausages, because it is fermented under warm condition with fluctuating temperatures of approximately 25 degrees C at night to 50 degrees C during sun drying. In this study, two of the 71 strains of lactic acid bacteria (LAB) isolated from natural urutan fermentation were used as starter cultures: Lactobacillus plantarum U201, the dominant LAB, and Pediococcus acidilactici U318, a bacteriocin producer. A soft urutan with yellowish brown color was produced using these strains as multiple starters. The starter cultures grew in characteristic succession which reconstructed the natural fermentation process. Lactobacilli were dominant until 48 h fermentation and pediococci dominated at the later stage of fermentation. Proliferation of starter cultures produced lactic acid which resulted in the decrease in pH and coagulation of soluble protein in urutan. Both strains could eliminate the Enterobacteriaceae in urutan after 24 h fermentation, and could suppress and eliminate the occurrence of micrococci at 120 h fermentation. By using a single starter culture, no succession was observed to occur in urutan and the time of elimination of Enterobacteriaceae was delayed. Thus, the strains of L. plantarum U201 and P. acidilactici U318 have great potential for use as multiple starter cultures in urutan fermentation.

Journal Article↗
PubMed1981

Role of Megasphaera elsdenii in the Fermentation of dl-[2-C]lactate in the Rumen of Dairy Cattle.

Since Megasphaera elsdenii ferments a variable part of dl-lactate to butyrate, measurement of the percentage of dl-lactate fermented to propionate via the acrylate pathway in rumen contents will underestimate the participation of M. elsdenii in the dl-lactate fermentation. The percentage of dl-[2-C]lactate fermented via the acrylate pathway and the percentage of dl-lactate fermented to butyrate can be measured with C-FT (Fourier transform)-nuclear magnetic resonance. On the average, the contribution of M. elsdenii to dl-lactate fermentation in the rumen of dairy cattle was found to be 74% (standard deviation, 13%), but differed with animal or diet. After feeding a cow readily fermentable carbohydrates, the contribution of M. elsdenii to the fermentation of dl-lactate increased as a consequence of catabolite repression in other dl-lactate-fermenting bacteria.

Journal Article↗
PubMed1986

Optimized batch fermentation of cheese whey-supplemented feedlot waste filtrate to produce a nitrogen-rich feed supplement for ruminants.

An optimized batch fermentation process for the conversion of cattle feedlot waste filtrate, supplemented with cheese whey, into a nitrogenous feed supplement for ruminants is described. Feedlot waste filtrate supplemented with cheese whey (5 g of whey per 100 ml) was fermented by the indigenous microbial flora in the feedlot waste filtrate. Ammonium hydroxide was added to the fermentation not only to maintain a constant pH but also to produce ammonium salts of organic acids, which have been shown to be valuable as nitrogenous feed supplements for ruminants. The utilization of substrate carbohydrate at pH 7.0 and 43 degrees C was >94% within 8 h, and the crude protein (total N x 6.25) content of the product was 70 to 78% (dry weight basis). About 66 to 69% of the crude protein was in the form of ammonia nitrogen. Lactate and acetate were the predominant acids during the first 6 to 8 h of fermentation, but after 24 h, appreciable levels of propionate and butyrate were also present. The rate of fermentation and the crude protein content of the product were optimal at pH 7.0 and decreased at a lower pH. For example, fermentation did not go to completion even after 24 h at pH 4.5. Fermentation proceeded optimally at 43 degrees C, less so at 37 degrees C, and considerably more slowly at 23 and 50 degrees C. Concentrations of up to 15 g of cheese whey per 100 ml of feedlot waste filtrate were fermented efficiently. Fermentation of feedlot waste filtrate obtained from animals fed low silage-high grain, high silage-low grain, or dairy rations resulted in similar products in terms of total nitrogen and organic acid composition.

Journal Article↗
PubMed1964

Pure Culture Fermentation of Brined Cucumbers.

The relative abilities of Pediococcus cerevisiae, Lactobacillus plantarum, L. brevis, and several other species of lactic acid bacteria to grow and produce acid in brined cucumbers were evaluated in pure culture fermentations. Such fermentations were made possibly by the use of two techniques, gamma radiation (0.83 to 1.00 Mrad) and hot-water blanching (66 to 80 C for 5 min), designed first to rid the cucumbers of naturally occurring, interfering, and competitive microbial groups prior to brining, followed by inoculation with the desired lactic acid bacteria. Of the nine species tested, strains of the three common to cucumber fermentations, P. cerevisiae, L. plantarum, and L. brevis, grew to the highest populations, and produced the highest levels of brine acidity and the lowest pH values in fermentations at 5.4 to 5.6% NaCl by weight; also, their sequence of active development in fermentations, with the use of a three-species mixture for inoculation, was in the species order just named. This sequence of occurrence was similar to that estimated by others for natural fermentations. The rates of growth and acid production in fermentations with a mixture of P. cerevisiae, L. plantarum, and L. brevis increased as the incubation temperature was increased from 21 to 27 to 32 C; however, the maximal populations and acidities attained were essentially the same for fermentations at each temperature. Further, these same three species were found to be the most salt tolerant of those tested; their upper limit for appreciable growth and measurable acid production was about 8% salt, whereas thermophilic species such as L. thermophilus, L. lactis, L. helveticus, L. fermenti, and L. delbrueckii exhibited a much lower salt tolerance, ranging from about 2.5 to 4.0%. However, certain strains of L. delbrueckii grew very rapidly in cucumbers brined at 2.5 to 3.0% salt, and produced sufficient acid in about 30 hr at 48 C to reduce the brine pH from above 7.0 to below 4.0. An inexpensive, pure culture fermentor which was suitable for gamma radiation, resistant to salt and acid, and which permitted repeated aseptic sampling of the fermenting brine, is illustrated and the specifications are given.

Journal Article↗
PubMed2001

Stuck and slow fermentations in enology: statistical study of causes and effectiveness of combined additions of oxygen and diammonium phosphate.

One hundred and seventy-eight musts from different regions in France were selected by enologists and fermented under standardized conditions. Two kinds of fermentation problems were distinguished: (a) slow and (b) sluggish (late-onset sluggish) and stuck (with residual sugar) fermentations. Slow fermentations, characterized by a low fermentation rate throughout the process, were always due to low assimilable nitrogen concentrations in the must. The advantages of using formol titration for measuring assimilable nitrogen are discussed. In contrast, sluggish and stuck fermentations, characterized by very low yeast viability at the end of fermentation, could not be predicted from the analytical data even though their probability was increased when the initial sugar concentration was high. All problems of stuck and sluggish fermentations (concerning 40% of the musts) were solved by supplying 7 mg/l oxygen and 300 mg/l diammonium phosphate at the halfway of the fermentation process, which confirmed (i) the importance of these two nutrients in enological practices and (ii) the importance of adding them at the right time.

Journal Article↗
PubMed2001

Effects of preculture variability on clavulanic acid fermentation.

The production profile of clavulanic acid by Streptomyces clavuligerus was shown to be strongly dependent on inoculum activity. Two sets of fermentations (A and B) were investigated at industrial pilot-plant scale using complex media. Type A fermentations were inoculated using late exponential growth phase mycelia. Type B fermentations were inoculated using mycelia harvested at stationary phase. Productivities throughout type A fermentations were consistently higher than type B, reaching a maximum at about 70 h and then decaying to the same final productivities at 140 h of type B runs. Several scheduling alternatives, based on combinations of the two inocula types and different fermentation lengths, were compared in terms of the overall process economics (fermentation and downstream). An increase of ca. 22% on the overall process profit is predicted using late exponential growth phase inocula and a fermentation duration of only 96 h. A new operating strategy was thus proposed for inoculum production based on the control of preculture activity using off-gas analysis. This method ensures higher productivity and better batch-to-batch reproducibility of clavulanic acid fermentations than traditional methods based on constant age inocula.

Anti-Bacterial Agents↗
PubMed2002

Differential proteomic analysis of Bacillus subtilis nitrate respiration and fermentation in defined medium.

A comparative investigation of protein expression by two-dimensional gel electrophoresis was conducted between Bacillus subtilis cultures grown in defined medium under aerobic, anaerobic nitrate respiration, or fermentation conditions. Defined medium specific for either nitrate respiration or fermentation allowed distinction between proteins induced by each individual growth process. Our differential protein profiling analysis between aerobic and anaerobic conditions showed that anaerobic fermentation induced at least 44 proteins and nitrate respiration induced at least 19 proteins compared to aerobic controls. Certain proteins were specifically induced during nitrate respiration or fermentation, while others were induced by both anaerobic processes. Eleven proteins induced by nitrate respiration and/or fermentation were identified by peptide mass matching using matrix-assisted laser desorption/ionization-time of flight mass spectrometry. Proteins encoded by feuA, hmp, and ytkD were induced by nitrate respiration. Proteins encoded by pyrR, sucD, trpC, and ywjH were induced by fermentation. Proteins encoded by acuB, pdhC, ydjL, and yvyD were induced by nitrate respiration and fermentation. This proteomic analysis has provided a more complete characterization of B. subtilis anaerobic growth and increased our understanding of its metabolic pathways of nitrate respiration and fermentation.

Bacillus subtilis↗