Microencapsulation and Application of Probiotic Bacteria Lactiplantibacillus plantarum 299v Strain.

Microencapsulation is an up-and-coming technology for maintaining the viability of probiotics. However, the effect of core-to-wall ratios and ratios of polysaccharides on the protection of the Lactiplantibacillus plantarum 299v strain has not been deeply discussed. Lyophilization of the Lp. plantarum 299v strain was conducted, and different core-to-wall ratios and ratios of maltodextrin (MD) and resistant starch (RS) were applied. Results demonstrated that the content of MD and RS had an influence on the yield and bulk density in both core-to-wall ratios (1:1 and 1:1.5). In addition, samples coated with a core-to-wall ratio of 1:1.5 had significantly higher viability than those coated with a core-to-wall ratio of 1:1. Moreover, samples coated with core-to-wall ratios of 1:1 and MD:RS 1:1, as well as core-to-wall ratios of 1:1.5 and MD:RS 3:1, had the highest cell number after simulated gastric fluid and simulated intestinal fluid testing, respectively. Furthermore, the optimal formulation for the application of microencapsulated Lp. plantarum 299v in apple juice (serving as a functional beverage) is listed as follows: core-to-wall ratios of 1:1 and MD:RS 1:1, with the fortification method, and stored at 4 °C. After 11 weeks of storage, the cell count was 8.28 log (CFU/mL). This study provided a strategy for Lp. plantarum 299v to achieve high viability in long-term storage and provides an application in functional apple beverages.

Enhancement of the enzymatic hydrolysis efficiency of wheat bran using the Bacillus strains and their consortium.

In the downstream process, the bioconversion of lignocellulosic biomass can be improved by applying a biological pretreatment procedure using microorganisms to produce hydrolytic enzymes to modify the recalcitrant structure of lignocellulose. In this study, various Bacillus strains (B. subtilis B.01162 and B.01212, B. coagulans B.01123 and B.01139, B. cereus B.00076 and B.01718, B. licheniformis B.01223 and B.01231) were evaluated for the degrading capacity of wheat bran in the submerged medium using enzymatic activities, reducing sugars and weight loss as indicators. The obtained results revealed that the B. subtilis B.01162, B. coagulans B.01123 and B. cereus B.00076 could be promising degraders for the wheat bran pretreatment. Besides, the application of their consortium (the combination of 2-3 Bacillus species) showed the positive effects on cellulose bioconversion compared with monocultures. Among them, the mixture of B. subtilis B.01162 and B. coagulans B.01123 increased significantly the cellulase, endo-glucanase, and xylanase enzyme activity resulting in accelerating the lignocellulose degradation. Our results served a very good base for the development of microbial consortium for biological pretreatment of lignocellulosic raw materials.

Synthesis of oligosaccharides with prebiotic potential by crude enzyme preparation from Bifidobacterium.

Oligosaccharides especially prebiotics take high attention in the development of foods because of their physiological properties in human health. They are generally synthetized enzymatically via transferases or hydrolases from mold or bacteria. The fact is that such oligosaccharides synthetized by probiotic bacteria, should be utilized by these microorganisms. This study focused on the production of oligosaccharides with prebiotic potential by crude enzyme preparation from bifidobacteria. Both monosubstrates and bisubstrates systems together with TLC and HPLC techniques, were applied. The crude enzyme preparation has different hydrolase activities such as α-glucosidase (2U/mL), ß-glucosidase (0.3 U/mL), α-galactosidase (1.2 U/mL), ß-galactosidase (0.4 U/mL), ß-fructosidase (11.5 U/mL). Additionally, it also has transglycosylation activities on lactose, lactulose, maltose and sucrose substrates. Two or three types of oligosaccharides were detected. The glycosyltransferase activity peaked at 45 °C, pH 6.6 and 30 g/100 mL substrate concentration. Significant high amount of oligosaccharides were formed in the case of lactose:sucrose combination than others. Both glucooligosaccharides and galactooligosaccharides are detected in the reaction mixtures of bisubstrate. When the lactose is present, the galactosyltransferation is predominated. One-one new types of oligosaccharides were detected in the reaction mixture of bioconversion. Among newly synthetized oligosaccharides, the fraction namely OS4 was utilized by probiotic bifidobacteria only. In conclusion, new types of galacto- and glucooligosaccharides with high prebiotic potentials were synthetized by the crude enzyme from probiotic Bifidobacterium strains.

Chemical and volatile composition of Pálinka produced using different commercial yeast strains of Saccharomyces cerevisiae.

Pálinka is Hungarian traditional alcoholic drink, and its quality is strongly depending on applied yeast strain. Unfortunately, all commercial yeast strains used the production of pálinka are selected for oenological purpose, and thus the efficacy and aroma releasing capacity are vary depending on the type and quality of fruit used. In this study, the fermentation efficacy of nine commercial yeast strains of Saccharomyces cerevisiae was focused. All strains were able to do alcoholic fermentation of apple juice quite efficiently, and the simple sugars (fructose, glucose and sucrose) were almost exhausted at the end of fermentation. Meanwhile, the alcohol production capacity and yield were no significant differences (around 9.17 v/v %-9.43 v/v %), whereas the ability of sugar consumption of strains Uvaferm Danstil A and Fermicru AR2 was stronger than others. The differences in the concentration and composition of volatile compounds were recorded. The highest levels of total volatile compounds were observed in samples fermented with Uvaferm Danstil A, Fermiblanc Arom, Vin-O-Ferm Roses, and Fermicru AR2. Meanwhile total volatile compounds, 2-methyl-1-propanol, 3-methyl-1-butanol, total higher alcohols, ethyl acetate, and total esters were considered as key parameters for describing the profile of fermented apple juices, whereas total fusel alcohols, 2-methyl-1-propanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and total volatile compounds were characteristic indicators of samples fermented with Uvaferm Danstil A. This work provides very good information of commercial yeast strains for industrial pálinka production.

Electrosprayed mucoadhesive alginate-chitosan microcapsules for gastrointestinal delivery of probiotics.

Besides viability protection, a sufficiently prolonged gastrointestinal retention of probiotics has emerged as critically important in improving the functional effectiveness of gastrointestinal delivery of these microorganisms. In this work, we formulated pure, resistant starch-reinforced and chitosan-coated alginate microparticles using an electrospray technique and evaluated their performance as mucoadhesive probiotic formulations for gastrointestinal delivery. In addition, we designed and successfully validated a novel experimental set-up of in vitro wash-off mucoadhesion test, using a portable and low-cost USB microscope for fluorescence imaging. In our test, pure chitosan microparticles (positive control) exhibited the greatest mucoadhesive property, whereas the alginate-resistant starch ones (negative control) were the least retentive on a gastric mucosa. These electrosprayed formulations were spherically shaped, with a size range of 30-600 µm (60-1300 µm with chitosan coating). Moreover, model probiotic Lactobacillus plantarum loaded in alginate-starch formulations was better protected against simulated gastric conditions than in alginate ones, but not better than in the chitosan-coated ones.

Effects of various polysaccharides (alginate, carrageenan, gums, chitosan) and their combination with prebiotic saccharides (resistant starch, lactosucrose, lactulose) on the encapsulation of probiotic bacteria Lactobacillus casei 01 strain.

The probiotics are extremely sensitive to various environmental factors, which imposes limitation on their health and functional effectiveness. Thus, development of delivery system for protection of viable cells while passing through different stages of the human digestion system is key factor in application of probiotic products. In our study, the effects of several polysaccharides such as alginate, κ-carrageenan, locust bean gum, gellan gum, xanthan gum and their combination with various prebiotic components (resistant starch, lactulose, lactosucrose) on encapsulation of probiotic Lactobacillus casei 01 strain were studied. Both regular and unregular beads with size distributions from 2 mm up to 5 mm were obtained. The encapsulation efficiencies varied from 64.4% up to 79%. Based on the texture's profiles, the capsules can be grouped into 5 clusters with squared Euclidean distance 3.5. Meanwhile, the starch-alginate and the lactosucrose LS55L - alginate beads were found to be the most stable and to have massive textural properties, whereas the gellan gum - xanthan gum and the chitosan coated alginate beads emerged as the softest. Encapsulation significantly improved the degree of gastric tolerance of probiotic cells even in the presence of pepsin. The INFOGEST in vitro digestion protocol was adapted to investigate the protection effects of different capsules. The highest survival (with loss rate of lower than 1 log CFU/g) was observed in the case of the cells encapsulated in starch-alginate beads. Moreover, the alginate microcapsules combined with lactosucrose LS55L also provided very promising shield for probiotics from the low pH of gastric conditions. Our findings suggest that incorporation of prebiotics into alginate-base encapsulation would be good idea in development of micro delivery systems that helps the survival of probiotics and their delivery to the target sites of action in human body.

Probiotic Beverage From Pineapple Juice Fermented With Lactobacillus and Bifidobacterium Strains.

Pineapple is an economically significant plant and the third most important fruit crop in the tropical and subtropical regions of the world. In this study, fermentation of pineapple juice with probiotic bacteria Lactobacillus and Bifidobacterium strains as well as changes of some properties in the beverage during storage were investigated. All tested strains exhibited good growth properties on pineapple juice without supplementation of any nutrient compounds. After 24 h fermentation, the cell counts of lactobacilli passed the level of 5*109 cfu/ml, while the cell number of bifidobacteria reached a level of 109 cfu/ml. The highest volumetric productivity (3.5*108 cfu/ml*h) was observed in L. plantarum 299V. The ratios of lactic acids to acetic acids in the cases of L. plantarum 299V and L. acidophilus La5 were 5.37 and 9.91, respectively. In the case of B. lactis Bb-12, the concentrations of lactic acid and acetic acid were 6 mM and 23 mM in natural juices, and 15 and 21 mM in the case of supplementation with prebiotics at the 16th h of fermentation, respectively. Additionally, supplementation with prebiotics at the initiation of fermentation resulted 7 mM lactic acid and 23 mM acetic acid at the end of fermentation. Fructose was the most preferred sugar for both lactobacilli and bifidobacteria. Both total phenolic content and antioxidant capacity increased slightly during fermentation and dropped during the storage period. The microbial population did not change significantly during the first month of storage. After the storage period (2 months), the probiotic bacteria lost about 0.11 log cfu/ml viability after treatment with 0.3% pepsin for 135 min, and a further 0.1 log cfu/ml after treatment with 0.6% bile salts. These values were 10 times higher than data from the fresh fermented pineapple juice. Our results are very promising and may serve as a good base for developing probiotic pineapple juice.

Lactic acid fermentation of apricot juice by mono- and mixed cultures of probiotic Lactobacillus and Bifidobacterium strains.

Apricot is a popular fruit in the world with rich in carbohydrates, vitamins and elements as well as has high antioxidant capacity. In this study, fermentation of this juice by mono- and mixed cultures was investigated. All tested strains exhibited good growth properties on apricot juice without any nutrient supplementation. In monoculture fermentation, 7.2, 7.25, 7.06 and 7.16 log (cfu/mL h) cell yields were observed for Bifidobacterium lactis Bb-12, Bifidobacterium longum Bb-46, Lactobacillus casei 01 and Lactobacillus acidophilus La-5 strains, respectively, and higher cell yields were obtained in the mixed culture fermentation. The antioxidant capacity increased slightly during fermentation. The concentration of acetic acid (27-48 mM) were about doubled in cases of the mixed culture fermentations than of monoculture fermentations (18-30 mM), while the levels of lactic acid were similar (70-90 mM). The relatively high values of these properties offer the potential for development of novel probiotic apricot juice.

Formation of novel hydrogel bio-anode by immobilization of biocatalyst in alginate/polyaniline/titanium-dioxide/graphite composites and its electrical performance.

A new bio-anode containing gel-entrapped bacteria in alginate/polyaniline/TiO2/graphite composites was constructed and electrically investigated. Alginate as dopant and template as well as entrapped gel was used for immobilization of microorganism cells. Increase of polyaniline concentration resulted an increase in the conductivity in gels. Addition of 0.01 and 0.02 g/mL polyaniline caused 6-fold and 10-fold higher conductivity, respectively. Furthermore, addition of 0.05 g/mL graphite powder caused 10-fold higher conductivity and 4-fold higher power density, respectively. The combination of polyaniline and graphite resulted 105-fold higher conductivity and 7-fold higher power-density output. Optimized concentrations of polyaniline and graphite powder were determined to be 0.02 g/mL and 0.05 g/mL, respectively. Modified hydrogel anode was successfully used in microbial fuel cell systems both in semi- and continuous operations modes. In semi-continuous mode, about 7.88 W/m3 power density was obtained after 13 h of fermentation. The glucose consumption rate was calculated to be about 7 mg glucose/h/1.2·107 CFU immobilized cells. Similar power density was observed in the continuous operation mode of the microbial fuel cell, and it was operated stably for more than 7 days. Our results are very promising for development of an improved microbial fuel cell with new type of bio-anode that have higher power density and can operate for long term.

Metabolomic approach assisted high resolution LC-ESI-MS based identification of a xenobiotic derivative of fenhexamid produced by Lactobacillus casei.

Fenhexamid is a widely used fungicide with one of the highest maximum tolerance limits approved for fruits and vegetables. The goal of this study was to examine if fenhexamid is metabolized by a nontarget organism, a Lactobacillus species (Lactobacillus casei Shirota), a probiotic strain of the human gastrointestinal tract. The assignment of bacterial derivatives of the xenobiotic fenhexamid was substantially facilitated by a metabolomic software based approach optimized for the extraction of molecular features of chlorine-containing compounds from liquid chromatography-electrospray ionization-quadrupole time-of-flight mass spectrometry data with an untargeted compound search algorithm. After validating the software with a set of seventeen chlorinated pesticides and manually verifying the result lists, eleven molecular features out of 4363 turned out to be bacterial derivatives of fenhexamid, revealing the O-glycosyl derivative as the most abundant one that arose from the fermentation medium of Lactobacillus casei Shirota in the presence of 100 µg/mL fenhexamid.