| 1. |
- Huang, Fang, et al.
(författare)
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Cultivation of the gut bacterium Prevotella copri DSM 18205T using glucose and xylose as carbon sources
- 2021
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Ingår i: MicrobiologyOpen. - : Wiley. - 2045-8827. ; 10:3
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Tidskriftsartikel (refereegranskat)abstract
- Prevotella copri DSM18205T is a human gut bacterium, suggested as a next-generation probiotic. To utilize it as such, it is, however, necessary to grow the species in a reproducible manner. Prevotella copri has previously been reported to be highly sensitive to oxygen, and hence difficult to isolate and cultivate. This study presents successful batch cultivation strategies for viable strain inoculations and growth in both serum bottles and a stirred tank bioreactor (STR), without the use of an anaerobic chamber, as long as the cells were kept in the exponential growth phase. A low headspace volume in the STR was important to reach high cell density. P. copri utilized xylose cultivated in Peptone Yeast Xylose medium (PYX medium), resulting in a comparable growth rate and metabolite production as in Peptone Yeast Glucose medium (PYG medium) in batch cultivations at pH 7.2.Up to 5 g/L of the carbon source was consumed, leading to the production of succinic acid, acetic acid, and formic acid, and cell densities (OD620 nm ) in the range 6-7.5. The highest yield of produced succinic acid was 0.63 ± 0.05 g/g glucose in PYG medium cultivations and 0.88 ± 0.06 g/g xylose in PYX medium cultivations.
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| 2. |
- Immerstrand, Tina, et al.
(författare)
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Characterization of the properties of Pediococcus parvulus for probiotic or protective culture use.
- 2010
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Ingår i: Journal of Food Protection. - 0362-028X. ; 73:5, s. 960-966
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Tidskriftsartikel (refereegranskat)abstract
- Pediococcus parvulus 2.6 (previously Pediococcus damnosus 2.6, here confirmed as P. parvulus by 16S DNA sequencing) displayed antibacterial activity toward several bacterial species, including isolates found as contaminants in oats, herein genetically identified as Bacillus cereus. No inhibition of Listeria monocytogenes was found under the conditions used. Antibacterial activity was retrieved after ammonium sulfate or acetone precipitation showed it to be peptide mediated. P. parvulus 2.6 has previously shown good technological properties in oat-based products. This, together with the currently found inhibition of food spoilage microorganisms like B. cereus, makes it suitable as a food protective culture. Survival trials of P. parvulus 2.6 at conditions mimicking the gastrointestinal tract were prompted by previously found cholesterol-lowering effects in humans after consumption of oat products cofermented by using P. parvulus 2.6 and Bifidobacterium spp. Viability was measured with in vitro, gutlike simulations at 37 degrees C. High survival was shown under two of three conditions (gastric juice, bile, and small intestine juice), defined as main obstacles of the gastrointestinal tract. The critical step was bile exposure. At a concentration of 20%, viability was low, but 0.3% bile (mean concentration in the intestine) did not have a major influence on growth. Viability of P. parvulus 2.6 was significantly decreased in gastric juice at pH 1.5 (with pepsin), but it was not significantly affected at pH 2.5, and was also improved at a lower pH in 20% oat milk. Viability was judged sufficient for colonization at gutlike conditions, qualifying the strain for further probiotic studies.
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| 3. |
- Lindström, Cecilia, et al.
(författare)
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An oat bran-based beverage reduce postprandial glycaemia equivalent to yoghurt in healthy overweight subjects.
- 2015
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Ingår i: International Journal of Food Sciences and Nutrition. - : Informa UK Limited. - 1465-3478 .- 0963-7486. ; 66:6, s. 700-705
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Tidskriftsartikel (refereegranskat)abstract
- An acute meal study was performed to determine postprandial glucose and insulin responses after consumption of two fermented oat bran-based beverages (with and without exopolysaccharides) and yoghurt. This randomized, single-blind, within-subject study included 18 healthy, overweight participants. Four breakfast meals, including a reference meal, were tested; all meals contained 50 g of available carbohydrates, but differed in energy and macronutrient composition. All experimental meals reduced the postprandial glucose response compared with the reference meal. The oat drinks as well as the yoghurt elicited higher early (0-15 min) insulin responses, but the overall insulinaemia were similar to the reference meal. A new food product containing fermented liquid oat bran and milk reduced the postprandial blood glucose response as efficiently as yoghurt after a high-glycaemic index white wheat bread meal, but the presence of microbial exopolysaccharides did not affect the outcome.
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| 4. |
- Lindström, Cecilia, et al.
(författare)
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Effects of Pediococcus parvulus 2.6 and its exopolysaccharide on plasma cholesterol levels and inflammatory markers in mice
- 2012
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Ingår i: AMB Express. - : Springer Science and Business Media LLC. - 2191-0855. ; 2:66
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Tidskriftsartikel (refereegranskat)abstract
- Intake of dietary fibres may reduce the prevalence of physiological risk factors of the metabolic syndrome, such as high plasma lipid levels and low-grade inflammatory state. Dietary fibres are usually of plant origin however microbial exopolysaccharides (EPSs) have analogue structures that could potentially exert similar physiological effects. Pediococcus parvulus 2.6 (Pd 2.6) excretes a ropy EPS and has previously shown probiotic potential. The aim of this work was to evaluate physiological effects of Pd 2.6 and its EPS in vivo. The live Pd 2.6 (both the ropy and non-ropy isogenic variant) and its purified EPS were fed to hypercholesterolemic LDL-receptor deficient mice for 6 weeks to investigate their effects on cholesterol levels and the inflammatory tone of the animals. Both variants of Pd 2.6 survived passage through the mouse gut fulfilling an important criterion of probiotics. The ability to produce EPS was conferring an advantage to survival (faecal recovery of 3.7 (1.9-8.7) vs. 0.21 (0.14-0.34) *108 CFU, P < 0.001, median and 25th and 75th percentiles). The ropy Pd 2.6 decreased the levels of soluble vascular cell adhesion molecule-1 compared to the EPS alone (591 ± 14 vs. 646 ± 13 ng/ml, P < 0.05). An increase in liver weight in mice fed the purified EPS was observed, but with no change in liver lipids. No changes in blood lipids were detected in any group. Further the EPS induced growth of the caecal tissue and increased the amount of caecal content showing bulking properties like that of a dietary fibre.
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| 5. |
- Lindström, Cecilia, et al.
(författare)
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Evaluation of commercial microbial hydrocolloids concerning their effects on plasma lipids and caecal formation of SCFA in mice
- 2012
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Ingår i: Food Hydrocolloids. - : Elsevier BV. - 0268-005X. ; 28:2, s. 367-372
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Tidskriftsartikel (refereegranskat)abstract
- Exopolysaccharides (EPS) are excreted by microorganisms into the surrounding environment and have been shown to have various physiological effects and are commonly used as food additives due to their rheological properties. Four commercially available microbial EPS with different polymeric structures and composition were tested in LDL receptor knock-out mice to investigate their effect on blood cholesterol, lipoproteins and caecal formation of SCFA. After four weeks on a Western diet supplemented with 4% EPS there were significant increases in caecal content and caecal tissue weight for the EPS groups compared to the control. The total pool of caecal short chain fatty acids was increased when mice were fed scleroglucan, xanthan and dextran. There were no differences in plasma cholesterol levels on the experimental diets compared to the control. Plasma triglycerides did not differ between groups. The results indicate that EPS supplementation to a Western diet may help in maintaining a healthy intestinal environment. (C) 2012 Elsevier Ltd. All rights reserved.
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| 6. |
- Lindström, Cecilia, et al.
(författare)
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Oral administration of live exopolysaccharide-producing Pediococcus parvulus, but not purified exopolysaccharide suppressed Enterobacteriaceae without affecting bacterial diversity in caecum of mice.
- 2013
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Ingår i: Applied and Environmental Microbiology. - 0099-2240. ; 79:16, s. 5030-5037
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Tidskriftsartikel (refereegranskat)abstract
- Growing evidence indicates that the gut microbiota could have an important role in the development of diet and lifestyle induced diseases. It has been shown that modulation of the gut microbiota by means of probiotics and prebiotics could improve host health. An oat based product fermented by the exopolysaccharide (EPS)-producing Pediococcus parvulus 2.6 has been reported to have a bifidogenic effect. To find out whether the effect could be attributed to the EPS or the bacterium, mice were fed a diet supplemented with 2 % purified EPS or 10(8) CFU/g of live P. parvulus 2.6 for six weeks. Both supplementations altered the gut microbiota composition but in different directions. Purified EPS not only significantly lowered the microbial diversity (P < 0.001) but decreased the bifidobacterial population (P = 0.01). In contrast, the live EPS-producing P. parvulus 2.6 antagonized Enterobacteriaceae without disturbing the homeostasis of the caecal microbiota.
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| 7. |
- Martensson, O, et al.
(författare)
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Growth and exopolysaccharide formation by Pediococcus damnosus 2.6 in beta-glucan suspensions of oat and barley
- 2005
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Ingår i: LWT - Food Science and Technology. - : Elsevier BV. - 0023-6438. ; 38:2, s. 151-155
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Tidskriftsartikel (refereegranskat)abstract
- The formation of exopolysaccharides (EPS) by Pediococcus damnosus strain 2.6 was investigated in two different high P-glucan suspensions of oat (OBC) and barley (BBC). Bacterial growth was confirmed by measuring pH, colony forming units (cfu), viscosity and ropiness during growth. Growth and an increase in viscosity of the beta-glucan suspension based on oat were observed whereas only a minor growth and no significant effect on viscosity was seen in the beta-glucans suspension based on barley. Higher bacterial growth and higher final viscosity and ropiness were observed in samples that were mixed with the OBC and an ordinary commercial oat-base (Adavena(R) G40). These results show the potential of using a combination of a high beta-glucan suspension of cereals to generate fermented products containing both high levels of native beta-glucans from oats or barley and also microbial beta-glucans from the starter culture.
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| 8. |
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| 9. |
- Mårtensson, O, et al.
(författare)
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Comparison of growth characteristics and exopolysaccharide formation of two lactic acid bacteria strains, Pediococcus damnosus 2.6 and Lactobacillus brevis G-77, in an oat-based, non-dairy medium.
- 2003
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Ingår i: LWT - Food Science and Technology. - 0023-6438. ; 36:3, s. 353-357
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Tidskriftsartikel (refereegranskat)abstract
- The fermentation characteristics of two strains of lactic acid bacteria (LAB), Lactobacillus brevis G-77 and Pediococcus damnosus 2.6 were compared in an oat-based, nondairy milk medium (Adavena® G40). Viscosity and ropiness were the main growth parameters studied. Both strains are reported to produce an exopolysaccharide (EPS) with a -glucan structure; in addition, the L. brevis strain produces also an EPS with an -glucan structure. Both strains were able to ferment and produce EPS in the oat-based, nondairy medium to the extent that an obvious change was observed in terms of viscosity and ropiness during the fermentation period. These results show the potential of both LAB strains as possible starter cultures in new kinds of fermented, nondairy milk products.
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| 10. |
- Mårtensson, Olof, et al.
(författare)
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Development of an oat-based sour milk-like product
- 2003
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Ingår i: Advances in Food Sciences. - 1431-7737. ; 25:3, s. 100-106
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Tidskriftsartikel (refereegranskat)abstract
- A fermented, oat-based product with properties resembling those of the traditional, Swedish, fermented milk product "filmjoelk" (sour milk) was developed. Com., mixed-strain, mesophilic starter cultures were grown in the oatbases M30, G40, and Oatly, which differed in the compn. of their carbohydrates. The exopolysaccharide-producer Pediococcus damnosus 2.6 was included to increase the viscosity of the G40 product. The CHN-19 culture chosen for the final product formulation produced a pleasant, buttery aroma, but a less sour taste than ordinary "filmjoelk". The addn. of glucose to M30 increased the acidification rate and gave a better aroma. A sensory anal. of two flavored products based on the G40 and M30 media, showed a higher acceptance of the M30 product. This study shows a potential for producing an oat-based "filmjoelk", but further work on consistency and taste is needed.
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