Short-chain fatty acids production by Bifidobacterium species in the presence of salep

BACKGROUND: Salep is obtained by grinding dried orchid tubers and used as a valuable ingredient in the food industry. Because of the glucomannan content of salep, it is thought to have prebiotic potential. However, there is little information in studies concerning the fermentation characteristics and potential prebiotic properties of salep. The objective of this study was to investigate the effect of salep on bifidobacterial growth by measuring the highest optical density (OD), calculating the specific growth rates, and determining the production of lactic acid and short-chain fatty acids (acetic, propionic, and butyric acid) as a result of bacterial fermentation. RESULT: The OD and pH values obtained in this study showed that salep was utilized as a source of assimilable carbon and energy by the Bifidobacterium species (BS). All Bifidobacterium strains produced lactic, acetic, propionic, and butyric acid, indicating that salep is readily fermented by these bacteria. Salep at 1% (w/v) showed a similar effect on bifidobacterial growth as that promoted by 1% (w/v) glucose used as a traditional carbon source. CONCLUSIONS: Bifidobacterium species can develop in media containing salep as well as in glucose and exhibit the potential to be used as new sources of prebiotics.

Removing the by-products acetic acid and NH4 + from the L-tryptophan broth by vacuum thin film evaporation during L-tryptophan production

Background: During L-tryptophan production by Escherichia coli, the by-products, acetic acid and NH4 +, accumulate in the fermentation broth, resulting in inhibited cell growth and activity and decreased L-tryptophan production. To improve the L-tryptophan yield and glucose conversion rate, acetic acid and NH4 + were removed under low-temperature vacuum conditions by vacuum scraper concentrator evaporation; the fermentation broth after evaporation was pressed into another fermenter to continue fermentation. To increase the volatilisation rate of acetic acid and NH4 + and reduce damage to bacteria during evaporation, different vacuum evaporation conditions were studied. Results: The optimum operating conditions were as follows: vacuum degree, 720 mm Hg; concentration ratio, 10%; temperature, 60°C; and feeding rate, 300 mL/min. The biomass yield of the control fermentation (CF) and fermentation by vacuum evaporation (VEF) broths was 55.1 g/L and 58.3 g/L at 38 h, respectively, (an increase of 5.8%); the living biomass yield increased from 8.9 (CF) to 10.2 pF (VEF; an increase of 14.6%). L-tryptophan production increased from 50.2 g/L (CF) to 60.2 g/L (VEF) (an increase of 19.9%), and glucose conversion increased from 18.2% (CF) to 19.5% (VEF; an increase of 7.1%). The acetic acid concentrations were 2.74 g/L and 6.70 g/L, and the NH4 + concentrations were 85.3 mmol/L and 130.9 mmol/L in VEF and CF broths, respectively. Conclusions: The acetic acid and NH4 + in the fermentation broth were quickly removed using the vacuum scraper concentrator, which reduced bacterial inhibition, enhanced bacterial activity, and improved the production of L-tryptophan and glucose conversion rate.

Fermentation process for production of apple-based kefir vinegar: microbiological, chemical and sensory analysis

Abstract The aim of this study was to develop a kefir apple-based vinegar and evaluate this fermentation process using new methodology with Biospeckle Laser. Brazilian kefir grains were inoculated in apple must for vinegar production. In this study, the microbial community present in kefir, and correspondent vinegar, was investigated using Matrix Assisted Laser Desorption/Ionization - Time of Flight Mass Spectrometry (MALDI-TOF MS) technique. Saccharomyces cerevisiae, Lactobacillus paracasei, Lactobacillus plantarum, Acetobacter pasteurianus and Acetobacter syzygii were the microbial species identified. S. cerevisiae, L. plantarum, A. pasteurianus and A. syzygii were found in smaller quantities at the beginning of the alcoholic fermentation, but were found throughout the alcoholic and acetic fermentation. Kefir grains were able to utilize apple must as substrate to produce ethanol, and acetic acid. Acetate, volatile alcohols and aldehydes in the vinegar-based kefir were also produced. The yield of acetic acid in the kefir vinegars was ∼79%. The acetic acid concentration was ∼41 g L-1, reaching the required standard for the Brazilian legislation accepts it as vinegar (4.0% acetic acid). Kefir vinegar showed good acceptance in the sensory analysis. The technology proposed here is novel by the application of immobilized-cell biomass (kefir grains) providing a mixed inocula and eliminating the use of centrifuge at the end of the fermentative process. This step will save energy demand and investment. This is the first study to produce apple vinegar using kefir grains.

Possibility of using apple pomaces in the process of propionic-acetic fermentation

Background: In 2014, apple production in EU countries amounted to 11.8 million tonnes. A constant increase in the production of these fruits will lead to the accumulation of thousands of tonnes of apple pomace (production waste). The amount of industrial apples is the highest - their proportiononthe market is estimated at 50-60%, of which over 95% is processed into juice. The proportion of pomace in the traditional pressing method accounts for 20% offruits used. Results: Analysis of the growth dynamics of wild strain Propionibacterium freudenreichii T82 in micro-cultures using different carbon sources showed that the highest bacterial growth occurs in an environment with fructose and the most intense biosynthesis of metabolites was found in medium containing only saccharose. It has been found that P. freudenreichii T82 used apple pomaces as a source of carbon. Propionic acid biosynthesis reached its maximum value in the 120th hour of cultivation (1.771 g/L). At this time, the content of the acetic acid produced reached the level of 7.049 g/L. Conclusions: Utilization of by-products is a significant challenge for manufacturing sites and the natural environment. The solution to this problem may involve the use of pomace as a medium component for microorganism cultivation, which is a source of industrially useful metabolites. This study examined the possibility of using apple pomace as a carbon source in the process of propionic-acetic fermentation via wild strain Propionibacterium freudenreichii T82 bacteria.

Bacteria isolated from Korean black raspberry vinegar with low biogenic amine production in wine

Abstract A high concentration of histamine, one of the biogenic amines (BAs) usually found in fermented foods, can cause undesirable physiological side effects in sensitive humans. The objective of this study is to isolate indigenous Acetobacter strains from naturally fermented Bokbunja vinegar in Korea with reduced histamine production during starter fermentation. Further, we examined its physiological and biochemical properties, including BA synthesis. The obtained strain MBA-77, identified as Acetobacter aceti by 16S rDNA homology and biochemical analysis and named A. aceti MBA-77. A. aceti MBA-77 showed optimal acidity % production at pH 5; the optimal temperature was 25 °C. When we prepared and examined the BAs synthesis spectrum during the fermentation process, Bokbunja wine fermented with Saccharomyces cerevisiae showed that the histamine concentration increased from 2.72 of Bokbunja extract to 5.29 mg/L and cadaverine and dopamine was decreased to 2.6 and 10.12 mg/L, respectively. Bokbunja vinegar prepared by A. aceti MBA-77 as the starter, the histamine concentration of the vinegar preparation step was decreased up to 3.66 mg/L from 5.29 mg/L in the wine preparation step. To our knowledge, this is the first report to demonstrate acetic acid bacteria isolated from Bokbunja seed vinegar with low spectrum BA and would be useful for wellbeing vinegar preparation.

Isolation, identification and characterization of regional indigenous Saccharomyces cerevisiae strains

Abstract In the present work we isolated and identified various indigenous Saccharomyces cerevisiae strains and screened them for the selected oenological properties. These S. cerevisiae strains were isolated from berries and spontaneously fermented musts. The grape berries (Sauvignon blanc and Pinot noir) were grown under the integrated and organic mode of farming in the South Moravia (Czech Republic) wine region. Modern genotyping techniques such as PCR-fingerprinting and interdelta PCR typing were employed to differentiate among indigenous S. cerevisiae strains. This combination of the methods provides a rapid and relatively simple approach for identification of yeast of S. cerevisiae at strain level. In total, 120 isolates were identified and grouped by molecular approaches and 45 of the representative strains were tested for selected important oenological properties including ethanol, sulfur dioxide and osmotic stress tolerance, intensity of flocculation and desirable enzymatic activities. Their ability to produce and utilize acetic/malic acid was examined as well; in addition, H2S production as an undesirable property was screened. The oenological characteristics of indigenous isolates were compared to a commercially available S. cerevisiae BS6 strain, which is commonly used as the starter culture. Finally, some indigenous strains coming from organically treated grape berries were chosen for their promising oenological properties and these strains will be used as the starter culture, because application of a selected indigenous S. cerevisiae strain can enhance the regional character of the wines.

Evaluation of stress tolerance and fermentative behavior of indigenous Saccharomyces cerevisiae

Sixty six indigenous Saccharomyces cerevisiae strains were evaluated in stressful conditions (temperature, osmolarity, sulphite and ethanol tolerance) and also ability to flocculate. Eighteen strains showed tolerant characteristics to these stressful conditions, growing at 42 ºC, in 0.04% sulphite, 1 mol L-1 NaCl and 12% ethanol. No flocculent characteristics were observed. These strains were evaluated according to their fermentative performance in sugar cane juice. The conversion factors of substrates into ethanol (Yp/s), glycerol (Yg/s) and acetic acid (Yac/s), were calculated. The highest values of Yp/s in sugar cane juice fermentation were obtained by four strains, one isolated from fruit (0.46) and the others from sugar cane (0.45, 0.44 and 0.43). These values were higher than the value obtained using traditional yeast (0.38) currently employed in the Brazilian bioethanol industry. The parameters Yg/s and Yac/s were low for all strains. The UFLA FW221 presented the higher values for parameter related to bioethanol production. Thus, it was tested in co-culture with Lactobacillus fermentum. Besides this, a 20-L vessel for five consecutive batches of fermentation was performed. This strain was genetically stable and remained viable during all batches, producing high amounts of ethanol. The UFLA FW221 isolated from fruit was suitable to produce bioethanol in sugar cane juice. Therefore, the study of the biodiversity of yeasts from different environmental can reveal strains with desired characteristics to industrial applications.

Short-term effects of thyroid hormones on lipogenic enzymes and 14C-acetate incorporation into various lipid classes: in vivo and in vitro studies.

Short-term effect of 3,5,3'-triiodothyronine (T3) and 3,5-diiodothyronine (T2) on lipid metabolism in the liver of Anabas testudineus was examined. In vivo injections of both T3 and T2 at a concentration of 10 ng/g body weight increased malic enzyme (ME), glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphogluconate dehydrogenase (6PGDH) activity compared to 6-propylthiouracil (6-PTU) treated group. Treatment of 6-PTU results in the accumulation 14C-acetate into fat and thyroid hormones' treatment reduce it. In vitro experiments show that malic enzyme activity is augmented only by high concentration of T3 (10(-7) M) where as all concentrations of T2 increase its activity. In vitro studies with T3 showed a biphasic effect on cholesterol content. Conversely T2 in vitro, reduced cholesterol content with all concentrations. From these results it can be concluded that both T3 and T2 have short-term effect on lipid metabolism in Anabas.

Diuretics physiology pharmacology and clinical use

Uricosuric diuretics have been developed to counteract renal urate retention accompanying diuretic-induced extracellular volume contraction. Their intrinsic uricosuric activity would prevent diuretic-induced hyperuricemia. Ticrynafen, a prototype uricosuric diuretic, has largely fallen into disuse because of hepatic toxicity. However, one lesson learned during the short period that ticrynafen was available in the US is that the administration of a potent uricosuric agent to a patient previously trated with diuretics can precipitate acute renal failure, possibly as a consequence of uric acid nephropathy. Another novel uricosuric diuretic, indacrinone, is composed of two enantiomorphic isomers exhibiting predominantly either a uricosuric or a natriuretic action. Manipulation of the isomer ratio currently is being attempted with a view toward obtaining a combination that produces little change in the serum urate during chronic diuretic therapy. Uricosuric diuretics have the therapeutic potential to treat hypertension and edematous states without increasing the serum urate. Although current information suggests that chronic asymptomatic hyperuricemia poses very little health hazard, future data could indicate that it may be desirable to maintain the serum urate near the normal range