Co-culturing Propionibacterium freudenreichii and Bifidobacterium animalis subsp. lactis improves short-chain fatty acids and vitamin B12 contents in soy whey.

The lack of vitamin B12 in unprocessed plant-based foods can lead to health problems in strict vegetarians and vegans. The main aim of this study was to investigate the potential synergy of co-culturing Bifidobacterium animalis subsp. lactis and Propionibacterium freudenreichii in improving production of vitamin B12 and short-chain fatty acids in soy whey. Different strategies including mono-, sequential and simultaneous cultures were adopted. Growth, short-chain fatty acids and vitamin B12 were assessed throughout the fermentation while free amino acids, volatiles, and isoflavones were determined on the final day. P. freudenreichii monoculture grew well in soy whey, whereas B. lactis monoculture entered the death phase by day 4. Principal component analysis demonstrates that metabolic changes in both sequential cultures did not show drastic differences to those of P. freudenreichii monoculture. However, simultaneous culturing significantly improved vitamin B12, acetic acid and propionic acid contents (1.3 times, 5 times, 2.5 times, compared to the next highest treatment [sequential cultures]) in fermented soy whey relative to other culturing modes. Hence, co-culturing of P. freudenreichii and B. lactis would provide an alternative method to improve vitamin B12, acetic acid and propionic acid contents in fermented foods.

High cell density sequential batch fermentation for enhanced propionic acid production from glucose and glycerol/glucose mixture using Acidipropionibacterium acidipropionici.

BACKGROUND: Propionic acid fermentation from renewable feedstock suffers from low volumetric productivity and final product concentration, which limits the industrial feasibility of the microbial route. High cell density fermentation techniques overcome these limitations. Here, propionic acid (PA) production from glucose and a crude glycerol/glucose mixture was evaluated using Acidipropionibacterium acidipropionici, in high cell density (HCD) batch fermentations with cell recycle. The agro-industrial by-product, heat-treated potato juice, was used as N-source. RESULTS: Using 40 g/L glucose for nine consecutive batches yielded an average of 18.76 ± 1.34 g/L of PA per batch (0.59 gPA/gGlu) at a maximum rate of 1.15 gPA/L.h, and a maximum biomass of 39.89 gCDW/L. Succinic acid (SA) and acetic acid (AA) were obtained as major by-products and the mass ratio of PA:SA:AA was 100:23:25. When a crude glycerol/glucose mixture (60 g/L:30 g/L) was used for 6 consecutive batches with cell recycle, an average of 35.36 ± 2.17 g/L of PA was obtained per batch (0.51 gPA/gC-source) at a maximum rate of 0.35 g/L.h, and reaching a maximum biomass concentration of 12.66 gCDW/L. The PA:SA:AA mass ratio was 100:29:3. Further addition of 0.75 mg/L biotin as a supplement to the culture medium enhanced the cell growth reaching 21.89 gCDW/L, and PA productivity to 0.48 g/L.h, but also doubled AA concentration. CONCLUSION: This is the highest reported productivity from glycerol/glucose co-fermentation where majority of the culture medium components comprised industrial by-products (crude glycerol and HTPJ). HCD batch fermentations with cell recycling are promising approaches towards industrialization of the bioprocess.

Utilization of propionic acid bacteria in the biotransformation of soy (tofu) whey: Growth and metabolite changes.

Soy whey, a by-product from the tofu and soy protein isolate industry was evaluated as a substrate for a biofortified beverage using several propionic acid bacteria (PAB). PAB growth and changes in sugars, organic acids, amino acids and isoflavones were investigated. Vitamin B12 and short-chain fatty acid (SCFA) production were measured over time. Acidipropionibacterium acidipropionici (DSM 20272) showed the highest growth, compared to the other three PABs (Propionibacterium freudenreichii [DSM 20271 and DSM 4902], A. jensenii [DSM 20535]). Acidipropionibacterium (DSM 20272 and DSM 20535) showed the best propionic acid and acetic acid production, while P. freudenreichii produced the most succinic acid. Propionibacterium freudenreichii exhibited significant vitamin B12 production at 4.06 ± 0.28 µg/L for DSM 20271, followed by 2.58 ± 0.22 µg/L for DSM 4902. Notably, all PAB displayed strong ß-glycosidase activities evidenced by the conversion of isoflavone glycosides to isoflavone aglycones. The stark differences between Acidipropionibacterium spp. and Propionibacterium spp. indicate that the former PAB is specialized in SCFA production, while the latter PAB is better at vitamin B12 bioenrichment. This study demonstrated the possibility of employing PAB fermentation to improve SCFA and vitamin B12 content. This can open avenues for a beverage or functional ingredient development.

Effect of metabolic activity of lactic acid bacteria and propionibacteria on cheese protein digestibility and fatty acid profile.

This study aimed at investigating the influence of different variants of bacterial starter cultures on the metabolism of the bacteria used, cheese protein digestibility, and fatty acid profile. The results revealed that lactic acid bacteria had a significant effect on the proportions of fatty acids in cheeses, with saturated fatty acids being predominant in in all cheese variants. Fatty acid proportions are complex and depend on the type of cheese culture and monoculture used. Additionally, the analysis of fatty acid composition showed variations in the proportion of saturated and unsaturated fatty acids, impacting the values of atherogenic and thrombogenic indices. Notably, the atherogenic index was highest in samples of mature cheeses obtained from a typical mesophilic cheese culture, whereas it was lowest in samples of fresh milk and mature cheeses obtained from a mesophilic cheese culture and monocultures of Lacticaseibacillus casei and Propionibacterium. The study also highlighted the influence of lactobacilli on the content of available free lysine, glycine, and methionine in cheese proteins. Mature cheeses obtained with Propionibacterium and L. casei starter cultures exhibited higher free lysine and glycine content compared with fresh cheeses and those obtained solely with the cheese culture. Additionally, mature cheeses obtained with starter cultures of mesophilic cheese culture, Propionibacterium, and L. casei had the highest free methionine content. Based on these findings, it is evident that the choice of cheese making cultures and monocultures can significantly affect the fatty acid composition and amino acid content of cheese and fresh milk, potentially bearing important health implications.

Efficacy and safety of Propionibacterium extract gel versus glyceryl trinitrate ointment in the treatment of chronic anal fissure: a randomized controlled trial.

AIM: Chronic anal fissure (CAF) is an extremely frequent finding in clinical practice. Several topical agents have been proposed for its treatment with the common goal of increasing anodermal blood flow to promote healing. The aim of this study was to compare the efficacy and safety of a Propionibacterium extract gel (PeG) and 0.4% glyceryl trinitrate ointment (GTN) in patients with CAF. METHOD: Patients were randomly allocated to a PeG or GTN group and medication was administered every 12 h for 40 days. The primary outcome was the success rate, as measured by a decrease in the REALISE scoring system for anal fissure at 10, 20 and 40 days after initiating either treatment. The secondary outcomes recorded at the same time points were healing rate, visual analogue scales for itching and burning, rate of complications and adverse events, patient quality of life and satisfaction, and cost analysis. RESULTS: A total of 120 patients were enrolled, and 96 patients (PeG, n = 53; GTN, n = 43) completed the primary outcomes. A significant decrease over time in the REALISE score was observed in both groups. Adverse events occurred more frequently in the GTN group than in the PeG group, peaking at visit 1 [37 (63.8%) vs. 2 (3.4%), respectively], with headache being the most prevalent. The between-treatment cumulative average costs per patient were significantly higher for GTN than that for PeG at each follow-up visit. There were no other significant differences between the two groups for any of the other outcomes. CONCLUSION: While there was no difference in healing rates between the two treatments, PeG was more cost-effective and associated with fewer adverse events.

Membrane-based continuous fermentation with cell recycling for propionic acid production from glycerol by Acidipropionibacterium acidipropionici.

BACKGROUND: Microbial production of propionic acid (PA) from renewable resources is limited by the slow growth of the producer bacteria and product-mediated inhibition. The present study evaluates high cell density continuous PA fermentation from glycerol (Gly) using Acidipropionibacterium acidipropionici DSM 4900 in a membrane-based cell recycling system. A ceramic tubular membrane filter of 0.22 µm pore size was used as the filtering device for cell recycling. The continuous fermentations were run sequentially at dilution rates of 0.05 and 0.025 1/h using varying glycerol concentrations and two different yeast extract concentrations. RESULTS: PA volumetric productivity of 0.98 g/L.h with a product yield of 0.38 gPA/gGly was obtained with 51.40 g/L glycerol at a yeast extract concentration of 10 g/L. Increasing the glycerol and yeast extract concentrations to 64.50 g/L and 20 g/L, respectively, increased in PA productivity, product yield, and concentration to 1.82 g/L.h, 0.79 gPA/gGly, and 38.37 g/L, respectively. However, lowering the dilution rate to 0.025 1/h reduced the production efficiency. The cell density increased from 5.80 to 91.83 gCDW/L throughout the operation, which lasted for a period of 5 months. A tolerant variant of A. acidipropoinici exhibiting growth at a PA concentration of 20 g/L was isolated at the end of the experiment. CONCLUSIONS: Applying the current approach for PA fermentation can overcome several limitations for process industrialization.

Developing a single-stage continuous process strategy for vitamin B12 production with Propionibacterium freudenreichii.

BACKGROUND: Vitamin B12 is a widely used compound in the feed and food, healthcare and medical industries that can only be produced by fermentation because of the complexity of its chemical synthesis. Besides, the use of Generally Recognized as Safe (GRAS) and Qualified Presumption of Safety (QPS) microorganisms, like Propionibacterium freudenreichii, especially non-GMO wild-type producers, are becoming an interesting alternative in markets where many final consumers have high health and ecological awareness. In this study, the production of vitamin B12 using the Propionibacterium freudenreichii NBRC 12391 wild-type strain was characterized and optimized in shake flasks before assessing several scale-up strategies. RESULTS: Initial results established that: (i) agitation during the early stages of the culture had an inhibitory effect on the volumetric production, (ii) 5,6-dimethylbenzimidazole (DMBI) addition was necessary for vitamin B12 production, and (iii) kinetics of vitamin B12 accumulation were dependent on the induction time when DMBI was added. When scaling up in a bioreactor, both batch and fed-batch bioprocesses proved unsuitable for obtaining high volumetric productivities mainly due to carbon source limitation and propionic acid inhibition, respectively. To overcome these drawbacks, an anaerobic single-phase continuous bioprocess strategy was developed. This culture strategy was maintained stable during more than 5 residence times in two independent cultures, resulting in 5.7-fold increase in terms of volumetric productivity compared to other scale-up strategies. CONCLUSION: Overall, compared to previously reported strategies aimed to reduce propionic acid inhibition, a less complex anaerobic single-phase continuous and more scalable bioprocess was achieved.

DELAYED ONSET Cutibacterium (FORMERLY Propionibacterium ) acnes ENDOPHTHALMITIS TRIGGERED BY INTRAVITREAL STEROID INJECTION.

PURPOSE: We report a case of delayed onset Cutibacterium acnes ( C. acnes , formerly Propionibacterium acnes or P. acnes ) endophthalmitis with the onset triggered by intravitreal steroid injection (triamcinolone acetonide) in a pseudophakic patient, 7 years after cataract surgery. METHODS/PATIENTS: A 67-year-old man presented with gradual worsening of vision, eye redness, and photosensitivity that started a month after intravitreal triamcinolone acetonide injection (Triescience, 4 mg/0.1 mL, Alcon Labs, Fort Worth, TX) for cystoid macular edema secondary to branch retinal vein occlusion in the right eye. The patient had undergone cataract surgery with intraocular lens in that eye 7 years prior. Examination showed the visual acuity of counting fingers at 3 feet and conjunctival injection, with 2+ anterior chamber cell and 2+ vitreous haze. Uveitis work up including angiotensin-converting enzyme, QuantiFERON Gold, and syphilis IgG screen was negative. Diagnostic pars plana vitrectomy with intravitreal injection of antibiotics was performed, and vitreous sample was sent for detailed laboratory analysis. RESULTS: Vitreous fluid analysis was positive for C. acnes and negative for viral, fungal, and malignant cells. Although the patient received intravitreal antibiotics injection twice, the intraocular infection and inflammation persisted which eventually required an intraocular lens and capsular bag removal, followed by insertion of a secondary intraocular lens later. CONCLUSION: Delayed onset C. acnes endophthalmitis may be triggered by an intravitreal steroid injection in pseudophakic patients.

Microaerobic metabolism of lactate and propionate enhances vitamin B12 production in Propionibacterium freudenreichii.

BACKGROUND: Propionibacterium freudenreichii is used in biotechnological applications to produce vitamin B12. Although cultured mainly in anaerobic conditions, microaerobic conditions can greatly enhance biomass formation in P. freudenreichii. Since B12 yields may be coupled to biomass formation, microaerobic conditions show great potential for increasing B12 yields in P. freudenreichii. RESULTS: Here we show biomass formation increases 2.7 times for P. freudenreichii grown in microaerobic conditions on lactate versus anaerobic conditions (1.87 g/L vs 0.70 g/L). Consumption of lactate in microaerobic conditions resulted first in production of pyruvate, propionate and acetate. When lactate was depleted, pyruvate and propionate were oxidised with a concomitant sixfold increase in the B12 titer compared to anaerobic conditions, showing potential for propionate and pyruvate as carbon sources for B12 production. Consequently, a fed-batch reactor with anaerobically precultured lactate-grown cells was fed propionate in microaerobic conditions resulting in biomass increase and production of B12. Vitamin yields increased from 0.3 [Formula: see text] B12 per mmol lactate in anaerobic conditions to 2.4 [Formula: see text] B12 per mmol lactate and 8.4 [Formula: see text] B12 per mmol propionate in microaerobic conditions. Yield per cell dry weight (CDW) increased from 41 [Formula: see text] per g CDW in anaerobic conditions on lactate to 92 [Formula: see text] per g CDW on lactate and 184 [Formula: see text] per g CDW on propionate in microaerobic conditions. CONCLUSIONS: Here we have shown both B12 yield per substrate and per CDW were highest on cells oxidising propionate in microaerobic conditions, showing the potential of propionate for biotechnological production of vitamin B12 by P. freudenreichii.

Metagenomics insight into bioaugmentation mechanism of Propionibacterium acidipropionici during anaerobic acidification of kitchen waste.

In the present study, a biochemical strategy for improving propionic acid production from kitchen waste acidification by bioaugmentation with Propionibacterium acidipropionici (P. acidipropionici) was investigated. When the inoculum of P. acidipropionici was 30% (w/w) of the seeding sludge, the propionic acid production increased by 79.57%. Further, bioaugmentation improved the relative abundance of Firmicute and Actinobacteria. The results of metagenomic analysis further reveal that the ATP-binding cassette (ABC) transporters and all related pathways of Propanoate metabolism (ko00640) were enriched when P. acidipropionici was added. For Propanoate metabolism, most functional genes involved in the conversion from Glycolysis / Gluconeogenesis (ko00010) to Propanoyl-CoA and conversion from Propanoyl-CoA to propionic acid were enhanced after bioaugmentation with P. acidipropionici, thereby promoting propionic acid production. As such, bioaugmentation with P. acidipropionici was effective in the anaerobic acidification of kitchen waste for propionic acid production.

A Unique Enhancement of Propionibacterium freudenreichii's Ability to Remove Pb(II) from Aqueous Solution by Tween 80 Treatment.

Microbial agents have promise for the bioremediation of Pb(II)-polluted environments and wastewater, the biodecontamination of foods, and the alleviation of toxicity in living organisms. The dairy bacterium Propionibacterium freudenreichii is poorly able to remove Pb(II) from aqueous solution at 25 ppm, ranging from 0 to 10% of initial concentration. Here, we report on an original strong enhancement of this activity (ranging from 75% to 93%, p < 0.01) following the addition of a polysorbate detergent (Tween® 80) during or either shortly after the growth of a P. freudenreichii culture. We evaluated the optimal Tween® 80 concentration for pretreatment conditions, documented the role of other detergents, and explored the possible mechanisms involved. Our results reveal a novel, environmentally friendly, low-cost pretreatment procedure for enhancing the selective removal of lead from water by probiotic-documented bacteria.

Use of apple pomace, glycerine, and potato wastewater for the production of propionic acid and vitamin B12.

Propionic acid bacteria (PAB) are a source of valuable metabolites, including propionic acid and vitamin B12. Propionic acid, a food preservative, is synthesized from petroleum refining by-products, giving rise to ecological concerns. Due to changing food trends, the demand for vitamin B12 has been expected to increase in the future. Therefore, it is necessary to look for new, alternative methods of obtaining these compounds. This study was conducted with an aim of optimizing the production of PAB metabolites using only residues (apple pomace, waste glycerine, and potato wastewater), without any enzymatic or chemical pretreatment and enrichment. Media consisting of one, two, or three industrial side-streams were used for the production of PAB metabolites. The highest production of propionic acid was observed in the medium containing all three residues (8.15 g/L, yield: 0.48 g/g). In the same medium, the highest production of acetic acid was found - 2.31 g/L (0.13 g/g). The presence of waste glycerine in the media had a positive effect on the efficiency of propionic acid production and P/A ratio. The concentration of vitamin B12 obtained in the wet biomass of Propionibacterium freudenreichii DSM 20271 ranged from 90 to 290 µg/100 g. The highest production of cobalamin was achieved in potato wastewater and apple pomace, which may be a source of the precursors of vitamin B12 - cobalt and riboflavin. The results obtained show both propionic acid and vitamin B12 can be produced in a more sustainable manner through the fermentation of residues which are often not properly managed. KEY POINTS: • The tested strain has been showed metabolic activity in the analyzed industrial side-streams (apple pomace, waste glycerine, potato wastewater). • All the side-streams were relevant for the production of propinic acid. • The addition of waste glycerine increases the propionic acid production efficiency and P/A ratio. • B12 was produced the most in the media containing potato wastewater and apple pomace as dominant ingredients.

Comparison of Propionibacterium genomes: CRISPR-Cas systems, phage/plasmid diversity, and insertion sequences.

The clustered regularly interspaced short palindromic repeats (CRISPR)-Cas systems constitute the adaptive immune system in prokaryotes that provide resistance against invasive genetic elements. The genus Propionibacterium comprises gram-positive, facultative anaerobe, non-spore-forming bacteria, and is the source of some B group vitamins such as B12 as well as bacteriocins. Some of the selected species of the genus Propionibacterium spp. were reclassified into the three genera in 2016 (Acidipropionibacterium spp., Pseudopropionibacterium spp., Cutibacterium spp.). Therefore, this study compared CRISPR/Cas systems, Cas 1 and repeat sequences phylogeny, phage/plasmid surveys as well as insertion sequences of new genera members. In this study, a total of 34 genomes of 13 species were observed with a bioinformatic approach. CRISPR-Cas + + and CRISPRDetect were used to detect CRISPR/Cas systems, direct repeats, and spacers. 39 CRISPR-Cas systems were detected. Type I-E, Type I-U, and one incomplete III-B CRISPR-Cas subtypes were identified. Most of the strains had Cas1/Cas4 fusion proteins. Pseudopropionibacterium propionicum strains had two types I-U and one of the CRISPR loci had csx17 cas genes. Common phage invaders were Propionibacterium phage E6, G4, E1, Anatole, and Doucette. The BLSM62 similarity score of all Cas1 sequences was 48.4% while the pairwise identity of repeat sequences was 48.7%. Common insertion sequences were ISL3, IS3, IS30. The diversity analysis of the CRISPR/Cas system in the genus Propionibacterium provided a new perspective for determining the role of the CRISPR-Cas system in the evolution of new genera.

Genomic rearrangements in the aspA-dcuA locus of Propionibacterium freudenreichii are associated with aspartase activity.

Propionibacterium freudenreichii is crucial in Swiss-type cheese manufacture. Classic propionic acid fermentation yields the nutty flavor and the typical eyes. Co-metabolism of aspartate pronounces the flavor of the cheese; however, it also increases the size of the eyes, which can induce splitting and reduce the cheese quality. Aspartase (EC 4.3.1.1) catalyzes the deamination of aspartate, yielding fumarate and ammonia. The aspartase activity varies considerably among P. freudenreichii strains. Here, the correlation between aspartase activity and the locus of aspartase-encoding genes (aspA ) and dcuA encoding the C4-dicarboxylate transporter was investigated in 46 strains to facilitate strain selection for cheese culture. Low aspartase activity was correlated with a particular genomic rearrangement: low in vitro aspartase activity always occurred in strains with gene clusters aspA - dcuA where the dcuA was frameshifted, producing a stop codon or was disrupted by an ISL3-like element. The low aspartase activity could be due to the protein sequence of the aspartase or a dysfunctional DcuA. The highest values of aspartase activity were detected in strains with aspA1 - aspA2-dcuA with a DcuA sequence sharing 99.07 - 100% identity with the DcuA sequence of strain DSM 20271 T and an additional C4-dicarboxylate transporter belonging to the DcuAB family.

Rapid identification of new isolates of Acidipropionibacterium acidipropionici by fluorescence in situ hybridization (FISH).

Acidipropionibacterium acidipropionici is widely used for many applications, such as propionic acid production, cereal silage, and also as probiotic. Due to this plethora of applications, new isolates of A. acidipropionici with improved features are being searched for. These new isolates must be accurately identified, however, most approaches become expensive and time-consuming when the number of isolates is high. On the contrary, fluorescence in situ hybridization allows the affordable, reliable, and rapid identification of microorganisms in pure cultures and environmental and medical samples. Therefore, the aim of this work was to apply a fluorescent in situ hybridization probe for the reliable identification of new A. acidipropionici isolates. To this end, probe Pap446, specific for A. acidipropionici, was validated by hybridization assays with strains of this species from different origins, other species of the same genus or family, and unrelated genera. Eight isolates with propionibacterium characteristics were obtained from milk and feces of cows. Probe Pap446, hybridized only with isolates III and VI. The identity of these isolates was further confirmed by PCR using group and species-specific primers for propionibacteria and 16S rDNA sequencing.

Using bifidobacterium and propionibacterium strains in probiotic consortia to normalize the gastrointestinal tract.

The gastrointestinal microflora regulates the body's functions and plays an important role in its health. Dysbiosis leads to a number of chronic diseases such as diabetes, obesity, inflammation, atherosclerosis, etc. However, these diseases can be prevented by using probiotics - living microorganisms that benefit the microflora and, therefore, improve the host organism's health. The most common probiotics include lactic acid bacteria of the Bifidobacterium and Propionibacterium genera. We studied the probiotic properties of the following strains: Bifidobacterium adolescentis АС-1909, Bifidobacterium longum infantis АС-1912, Propionibacterium jensenii В-6085, Propionibacterium freudenreichii В-11921, Propionibacterium thoenii В-6082, and Propionibacterium acidipropionici В-5723. Antimicrobial activity was determined by the 'agar blocks' method against the following test cultures: Escherichia coli ATCC 25922, Salmonella enterica ATCC 14028, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa B6643, Proteus vulgaris ATCC 63, and Listeria monocytogenes ATCC 7644. Moderate antimicrobial activity against all the test cultures was registered in Bifidobacterium adolescentis АС-1909, Propionibacterium jensenii В-6085, and Propionibacterium thoenii В-6082. Antioxidant activity was determined by the DPPH inhibition method in all the lactic acid strains. Our study indicated that some Propionibacterium and Bifidobacterium strains or, theoretically, their consortia could be used as probiotic cultures in dietary supplements or functional foods to prevent a number of chronic diseases.

Detailed protocol for germ-free Drosophila melanogaster colonization with Propionibacterium spp. biofilms.

In this protocol, we describe a germ-free Drosophila melanogaster model to investigate anaerobic bacterial biofilms. We detail how to establish Propionibacterium spp. biofilms in the fruit fly's gut using an easy to carry out method. For complete details on the use and execution of this protocol, please refer to Bronnec and Alexeyev (2021) and Bronnec et al. (2022).

Evaluation of a Gel Containing a Propionibacterium Extract in an In Vivo Model of Wound Healing.

Inappropriate wound healing (WH) management can cause significant comorbidities, especially in patients affected by chronic and metabolic diseases, such as diabetes. WH involves several different, partially overlapping processes, including hemostasis, inflammation, cell proliferation, and remodeling. Oxidative stress in WH contributes to WH impairment because of the overexpression of radical oxygen species (ROS) and nitrogen species (RNS). This study aimed to evaluate the in vitro antioxidative action of a gel containing a Propionibacterium extract (Emorsan® Gel) and assess its skin re-epithelialization properties in a mouse model of WH. The scavenging effects of the bacterial extract were assessed in vitro through the ABTS and DPPH assays and in L-929 murine fibroblasts. The effects of the Emorsan® Gel were studied in vivo in a murine model of WH. After WH induction, mice were treated daily with vehicle or Emorsan® Gel for 6 or 12 days. According to the in vitro tests, the Propionibacterium extract exerted an inhibitory effect on ROS and RNS, consequently leading to the reduction in malondialdehyde (MDA) and nitrite levels. Before proceeding with the in vivo study, the Emorsan® Gel was verified to be unabsorbed. Therefore, the observed effects could be ascribed to a local action. The results obtained in vivo showed that through local reduction of oxidative stress and inflammation (IL-1ß, TNF-α), the Emorsan® Gel significantly reduced the infiltration of mast cells into the injured wound, leading to the amelioration of symptoms such as itch and skin irritation. Therefore, the Emorsan® Gel improved the speed and percentage of wound area closure by improving the tissue remodeling process, prompting vascular-endothelial growth factor (VEGF) and transforming growth factor (TGF)- ß production and reducing the expression of adhesion molecules. Emorsan® Gel, by its ability to inhibit free radicals, could reduce local inflammation and oxidative stress, thus enhancing the speed of wound healing.

Properties of Rice-Based Beverages Fermented with Lactic Acid Bacteria and Propionibacterium.

In recent times, consumers have shown increasing interest in plant substitutes for fermented dairy products. This study aimed to investigate the properties of yogurt-type rice-based beverages fermented with lactic acid bacteria and Propionibacterium. The changes in pH, viable population of bacteria, physical properties, and carbohydrate content of these beverages were tested. Fermentation using only Propionibacterium was insufficient to obtain a product with an acidity level similar to that of milk-based yogurt (pH < 4.5). After fermentation, the tested beverages had a high number of Lactobacillus sp. (7.42−8.23 log10 CFU/mL), Streptococcus thermophilus (8.01−8.65 log10 CFU/mL), and Bifidobacterium animalis subsp. lactis (8.28−8.50 log10 CFU/mL). The hardness (2.90−10.40 N) and adhesiveness (13.79−42.16 mJ) of the samples after 14 days of storage at 6 °C varied depending on the starter culture used. The syneresis of all samples ranged between 29% and 31%, which was lower or close to that of milk-based yogurts. The content of individual sugars in the samples also varied depending on the starter culture used for fermentation. The results suggest that the combination of lactic and propionic fermentation helps in the production of rice-based yogurt-type milk substitutes.

Fermentation strategies to improve propionic acid production with propionibacterium ssp.: a review.

Propionic acid (PA) is a carboxylic acid applied in a variety of processes, such as food and feed preservative, and as a chemical intermediate in the production of polymers, pesticides and drugs. PA production is predominantly performed by petrochemical routes, but environmental issues are making it necessary to use sustainable processes based on renewable materials. PA production by fermentation with the Propionibacterium genus is a promising option in this scenario, due to the ability of this genus to consume a variety of renewable carbon sources with higher productivity than other native microorganisms. However, Propionibacterium fermentation processes present important challenges that must be faced to make this route competitive, such as: a high fermentation time, product inhibition and low PA final titer, which increase the cost of product recovery. This article summarizes the state of the art regarding strategies to improve PA production by fermentation with the Propionibacterium genus. Firstly, strategies associated with environmental fermentation conditions and nutrition requirements are discussed. Subsequently, advantages and disadvantages of various strategies proposed to improve process performance (high cell concentration by immobilization or recycle, co-culture fermentation, genome shuffling, evolutive and metabolic engineering, and in situ recovery) are evaluated.