Single Culture Fermentation Research Articles

Proximate Analysis and Digestibility of Modified Corn Flour

Abstract: The quality of corn flour can improve through a modification process. The modification method that can be done to improve the characteristics of corn flour is through a controlled fermentation process accompanied by pregelatinization. This study aims to determine the effect modification of corn flour by spontaneous fermentation, controlled fermentation using Lactobacillus fabifermentans or Aspergillus sp culture and mixed culture of L. fabifermentans and Aspergillus sp (1:3) followed by pregelatinization at 80ºC for 15 minutes. The treatment variables in this study were spontaneous fermentation, controlled fermentation using single cultures of L. fabifermentans or Aspergillus sp., and mixed cultures of these microbes with a ratio of 1:3. This study consisted of 4 treatments with three groups each. This research is an experimental study using Randomized Block Design (RBD). Observation variables in this study were proximates tests (moisture content, ash, protein, fat, and carbohydrates) and starch digestibility. The data were processed using the SPSS version 22 program, with the method analysis of variance (ANOVA), and continued with Duncan’s Multiple Range Test (DMRT). The results of variance analysis from spontaneous fermentation treatments, single culture fermentation of L. fabifermentans or Aspergillus sp, and mixed cultures of L. fabifermentans and Aspergillus sp (1:3) gave significant effect on moisture content, fat, carbohydrates, and starch digestibility of modified corn flour. The best-modified corn flour was obtained by controlled fermentation treatment using L. fabifermentans followed by pregelatinization with characteristics of moisture content 14.46%, ash 0.13%, protein 7.41%, fat 0.65%, carbohydrates 80.06%, and starch digestibility 87.15%.

Mixed Culture Cultivation in Microbial Bioprocesses.

Mixed culture cultivation is well renowned for industrial applications due to its technological and economic benefits in bioprocess, food processing, and pharmaceutical industries. A mixed consortium encompasses to achieve growth in unsterile conditions, robustness to environmental stresses, perform difficult functions, show better substrate utilization, and increase productivity. Hence, mixed cultures are being valorized currently and has also augmented our understanding of microbial activities in communities. This chapter covers a wide range of discussion on recent improvements in mixed culture cultivation for microbial bioprocessing and multifarious applications in different areas. The history of microbial culture, microbial metabolism in mixed culture, biosynthetic pathway studies, isolation and identification of strains, along with the types of microbial interactions involved during their production and propagation, are meticulously detailed in the current chapter. Besides, parameters for evaluating mixed culture performance, large-scale production, and challenges associated with it are also discussed vividly. Microbial community, characteristics of single and mixed culture fermentation, and microbe-microbe interactions in mixed cultures have been summarized comprehensively. Lastly, various challenges and opportunities in the area of microbial mixed culture that are obligatory to improve the current knowledge of microbial bioprocesses are projected.

Exploring the impact of co-fermentation Saccharomyces cerevisiae and Lactobacillus sp. on stingless bee-honey cider fermentation

Stingless bee honey is a nutritious food that contains a variety of vitamins, minerals, enzymes, and antioxidants. It is known to have higher nutritional and medicinal properties compared to honey produced by other bee species. Cider is a well-known functional drink that contains high antioxidants, which can help protect against cellular damage caused by free radicals. This study aimed to investigate the potential of co-fermentation with yeast (Saccharomyces cerevisiae) and bacterium (Lactobacillus sp.) in producing high-antioxidant honey cider when compare with standard antioxidant. The results showed that honey cider co-fermented with both microorganisms for 14 days had significantly higher antioxidant activity (145.27 ± 0.20 µg TE/mL) compared to single culture fermentation (p < 0.05). Gas chromatography-mass spectrometry (GC-MS) analysis revealed the presence of several bioactive compounds in the stingless bee honey cider. These compounds include methylenecyclopropanecarboxylic acid, 2(5H)-furanone, 2-methylbicyclo[4.3.0]non-1(6)-ene, bicyclo[3.1.0]hex-2-ene, 4-methyl-1-(1-methylethyl), D-limonene, benzene, 1-(1-butenyl)-4-methoxy, and phytol. These compounds possess various beneficial activities, such as antioxidant, anti-inflammatory, antimicrobial, and anticancer properties. The identification of these compounds in the stingless bee honey cider suggests that it may have potential health benefits beyond its nutritional value. The co-fermentation approach using S. cerevisiae and Lactobacillus sp. could be considered a promising strategy for developing antioxidant-enriched honey cider with potential health benefits.

Modelling the physiological status of yeast during wine fermentation enables the prediction of secondary metabolism.

Saccharomyces non-cerevisiae yeasts are gaining momentum in wine fermentation due to their potential to reduce ethanol content and achieve attractive aroma profiles. However, the design of the fermentation process for new species requires intensive experimentation. The use of mechanistic models could automate process design, yet to date, most fermentation models have focused on primary metabolism. Therefore, these models do not provide insight into the production of secondary metabolites essential for wine quality, such as aromas. In this work, we formulate a continuous model that accounts for the physiological status of yeast, that is, exponential growth, growth under nitrogen starvation and transition to stationary or decay phases. To do so, we assumed that nitrogen starvation is associated with carbohydrate accumulation and the induction of a set of transcriptional changes associated with the stationary phase. The model accurately described the dynamics of time series data for biomass and primary and secondary metabolites obtained for various yeast species in single culture fermentations. We also used the proposed model to explore different process designs, showing how the addition of nitrogen could affect the aromatic profile of wine. This study underlines the potential of incorporating yeast physiology into batch fermentation modelling and provides a new means of automating process design.

Assessment of Tannin Tolerant Non-Saccharomyces Yeasts Isolated from Miang for Production of Health-Targeted Beverage Using Miang Processing Byproducts

This research demonstrated an excellent potential approach for utilizing Miang fermentation broth (MF-broth), a liquid residual byproduct from the Miang fermentation process as a health-targeted beverage. One hundred and twenty yeast strains isolated from Miang samples were screened for their potential to ferment MF-broth and four isolates, P2, P3, P7 and P9 were selected, based on the characteristics of low alcoholic production, probiotic properties, and tannin tolerance. Based on a D1/D2 rDNA sequence analysis, P2 and P7 were identified to be Wikerhamomyces anomalus, while P3 and P9 were Cyberlindnera rhodanensis. Based on the production of unique volatile organic compounds (VOCs), W. anomalus P2 and C. rhodanensis P3 were selected for evaluation of MF-broth fermentation via the single culture fermentation (SF) and co-fermentation (CF) in combination with Saccharomyces cerevisiae TISTR 5088. All selected yeasts showed a capability for growth with 6 to 7 log CFU/mL and the average pH value range of 3.91-4.09. The ethanol content of the fermented MF-broth ranged between 11.56 ± 0.00 and 24.91 ± 0.01 g/L after 120 h fermentation, which is categorized as a low alcoholic beverage. Acetic, citric, glucuronic, lactic, succinic, oxalic and gallic acids slightly increased from initial levels in MF-broth, whereas the bioactive compounds and antioxidant activity were retained. The fermented MF-broth showed distinct VOCs profiles between the yeast groups. High titer of isoamyl alcohol was found in all treatments fermented with S. cerevisiae TISTR 5088 and W. anomalus P2. Meanwhile, C. rhodanensis P3 fermented products showed a higher quantity of ester groups, ethyl acetate and isoamyl acetate in both SF and CF. The results of this study confirmed the high possibilities of utilizing MF-broth residual byproduct in for development of health-targeted beverages using the selected non-Saccharomyces yeast.

Designing synthetic consortia of Trichoderma strains that improve antagonistic activities against pathogens and cucumber seedling growth

BackgroundTrichoderma spp. are important agricultural biocontrol microorganisms that are often used as effective components of microbial fungicides and microbial biofertilizers. However, most of these products are prepared by a single strain in monoculture, which significantly limits the biocontrol efficiency and stability of Trichoderma products. Therefore, the establishment of a design and screening approach for consortia with multi-Trichoderma strains for co-culture is of great importance to overcome the shortage of traditional Trichoderma biocontrol products.ResultsFirst, 15 Trichoderma strains were screened in terms of mycelium growth rate, antagonistic activity to a variety of pathogens, stress tolerance to high temperature and salt stress, and cucumber seedling growth promotion level. Then, the combinations of Trichoderma asperellum GDSF1009 (CGMCC NO. 9512), Trichoderma asperelloides Z4-1 (CGMCC NO. 40245), Trichoderma harzianum 10569 (CGMCC NO. 40246), and T. asperellum 10264 (CGMCC NO. 22404) were finally screened as an optimal consortium for co-culture underlying the levels of plant growth-promoting and antagonistic activity to Fusarium oxysporum and seed germination promotion relative to the monoculture of a single strain. Consortia with multiple co-cultured strains were found to generate larger amounts of free amino acids than those from the monoculture of a single strain, and a pot assay also indicated that metabolites of co-cultures were able to promote cucumber seedling growth superior to that with monoculture of a single strain, even though the promotion was better than from simply mixed cultures from each of the four Trichoderma strains. Taken together, the co-culture consortia composed of the four compatible interactive Trichoderma strains was a potential novel multiple strain biocontrol agent based on the combination of synthetic consortia design and co-culture. In the field experiment, we found that the growth-promoting effect of the co-culture fermentation filtrate was better than that of the single culture fermentation filtrate. Compared with T-Z4-1, T-1009, T-10264 and T-10569, the plant height of cucumber was increased by 22.99%, 42.06%, 24.18% and 30.09%, respectively, and the stem diameter was increased by 16.59%, 18.83%, 13.65% and 14.70%, respectively.ConclusionAn approach to designing and screening Trichoderma consortia for co-culture was established. The consortia co-culture presented a better performance in antagonistic activity and cucumber growth compared with a monoculture of a single strain. Thus, it is of great significance to lay the foundation for the creation of a novel Trichoderma biofungicide or biomanure to resist cucumber Fusarium wilt and promote cucumber growth.

Using wild yeasts to modulate the aroma profile of low-alcoholic meads.

In recent years, ample research has focused on applying wild (especially non-Saccharomyces) yeasts in producing alcoholic beverages. Common characteristics of wild yeast strains include simultaneous high production of fruity and floral aroma compounds and low ethanol production. In this study, mead starter cultures were selected based on preliminary screening of wild yeast strains from a Brazilian culture collection (n = 63) for their ability to produce aroma-active compounds. The selected strains included one strain of Saccharomyces cerevisiae and three non-Saccharomyces strains (Pichia jadinii, Torulaspora delbrueckii, and Kluyveromyces lactis). These strains were used to ferment honey must prepared with Aroeira honey, adjusted to 24°Brix, which took 36days to complete. Single culture fermentations and co-fermentations with S. cerevisiae and non-Saccharomyces strains were carried out. The quality of the produced beverages was evaluated by sugar consumption and production of alcohols and organic acids, analyzed with high-performance liquid chromatography. The volatile organic compound composition was analyzed with gas chromatography-mass spectrometry. Meads with various ethanol amounts (4.7-11.0% v/v) and residual sugar contents (70.81-160.25gl-1) were produced. In addition, in both single-strain fermentation and co-fermentation with S. cerevisiae, meads produced with either Torulaspora delbrueckii or Kluyveromyces lactis had a roughly three-fold higher content of honey-aroma compound phenethyl acetate and a higher hedonic impression score than meads produced with only S. cerevisiae. These results demonstrated non-Saccharomyces yeasts' ability to increase aroma complexity and improve the sensory quality of low-alcoholic meads.

HARNESSING THE NUTRITIONAL QUALITY OF PAWPAW AND PINEAPPLE FRUITS FOR PILOT SCALE PRODUCTION OF WINE

Fermenting blended fruits has been observed to have positive cumulative health benefits. Pawpaw and Pineapple have well-known nutritive and health benefits. This study evaluated the role of fermentation on the nutritional and anti-nutritional compositions of pawpaw-pineapple juice blends using single and mixed starter cultures. Fermentation of pawpaw-pineapple juice blends in varying ratios: 1:1, 1:3 and 3:1 tagged Samples A, B, and C respectively was performed for five days after which the nutritional and anti-nutritional compositions were analyzed using standard methods. The findings revealed an increase in the concentration of all the proximate parameters except carbohydrate. The results also showed that sample A was better in nutritive quality than sample B and C by 8.55% and 3.92% respectively. The mono-cultural fermentation of sample A by Saccharomyces cerevisiae yielded the highest nutritional value (30.12%) as compared to mixed (25.35%) and single culture fermentation of Lactobacillus delbreukii (23.40%) and Leuconostoc mesenteroides (21.13%). The mineral composition of sample A (37.60%) with respect to organism was also observed to be significantly higher than sample B (28.82%) and C (33.58%). Overall, the single culture of S. cerevisiae gave the highest mineral output in all the blended ratios. The levels of the anti-nutrients were better reduced by a single culture of S. cerevisiae. Furthermore, the mono-cultural fermentation of sample A by S. cerevisiae produced the highest alcoholic content. Mono-cultural fermentation of pawpaw-pineapple juice in ratio 1:1 by S. cerevisiae is most efficient in obtaining the highest nutritional value and alcoholic content in pawpaw-pineapple wine.

Co-culture submerged fermentation by lactobacillus and yeast more effectively improved the profiles and bioaccessibility of phenolics in extruded brown rice than single-culture fermentation

This study aims to investigate the effects of fermentation on the phenolic components and their bioaccessibility in extruded brown rice (EBR). The saccharified solution of EBR (SS-EBR) depicted higher phenolics when fermented by single or co-culture of Lactobacillusplantarum, Lactobacillus fermentum and Saccharomyces cerevisiae for 24 h at 37 °C. The co-culture fermented SS-EBR more significantly enhanced free, conjugated and bound phenolics and flavonoids with total increment of 93.3% and 61.3%, respectively. Fermentation changed the contents and compositions of phenolics in each fraction with more than 10-fold increase in vanillic acid and quercetin contents. Ferulic, p-cumaric and chlorogenic acids were increased by 83.5%, 52.2% and 113.4%, respectively, while kaempferol and cinnamic acid were found only in fermented SS-EBR. Fermentation also improved the oxygen radical absorption capacity (ORAC) and the bioaccessible phenolics in SS-EBR. Hence, the co-culture fermented SS-EBR, can be utilized as a functional supplement to provide more bioaccessible antioxidants.

Influence of Nutrient Supplementation on Torulaspora Delbrueckii Wine Fermentation Aroma

This study was performed with the aim of characterizing the fermentative performance of three commercial strains of Torulaspora delbrueckii and their impact on the production of volatile and non-volatile compounds. Laboratory-scale single culture fermentations were performed using a commercial white grape juice. The addition of commercial nutrient products enabled us to test the yeasts under two different nutrient conditions. The addition of nutrients promoted fermentation intensity from 9% to 20 % with significant differences (p < 0.05) among the strains tested. The strain diversity together with the nutrient availability influenced the production of volatile compounds.

The impact of Saccharomyces and non-Saccharomyces yeasts on wine colour: A laboratory study of vinylphenolic pyranoanthocyanin formation and anthocyanin cell wall adsorption

Wine fermentation is a complex process driven by yeasts, which influence the key properties of wine quality: aroma, flavour and colour. We investigated 95 different Saccharomyces and non-Saccharomyces strains for their impact on wine colour through the synthesis of the stable pigments, pyranoanthocyanins. All strains were screened for their hydroxycinnamate decarboxylase (HCDC) activity that varied from 0.0% to 91.1%. Eight strains that showed more than 40% HCDC activity were further studied for vinylphenolic pyranoanthocyanin formation. Fermentations were carried out in deep well microtiter plates using synthetic grape must containing Pinot Noir skin extract supplemented with p-coumaric acid. Two strains Pichia guilliermondii ZIM624 and Wickerhamomyces anomalus S138 synthesized vinylphenolic pyranoanthocyanins in the highest concentration in single culture fermentations, 40.2 and 38.5 mg L−1, respectively. The highest produced concentration of vinylphenolic pyranoanthocyanins in co-inoculation experiments was 16.4 mg L−1 compared to 29.8 mg L−1 in sequential fermentations. For the first time, S. paradoxus strains were assessed for pyranoanthocyanin formation. Selected strains were also tested as mono-cultures for adsorption of anthocyanins on yeast cell walls and all strains showed anthocyanin and pyranoanthocyanin adsorption to their cell wall with Metschnikowia reukafii ZIM2019 showing the highest adsorbing capability (9.1%).

Assessment of chemical composition and sensorial properties of ciders fermented with different non-Saccharomyces yeasts in pure and mixed fermentations

This work presents the attempt to enhance the flavor complexity of cider fermented by different non-Saccharomyces species. Pichia kluyveri and Hanseniaspora vineae pure cultures were used as reference ciders. Mixed cultures between all 4 species gave 5 fermentations, where Hanseniaspora uvarum or Torulaspora quercuum were included for apple juice fermentation. Chemical composition and sensorial properties of all ciders were studied. The results indicated that the growth of P. kluyveri and H. vineae were interreacted and also affected by H. uvarum and T. quercuum. H. vineae was more capable of consuming sugar than P. kluyveri. Ciders from the single culture fermentation with P. kluyveri (Pk), as well as from mixed fermentation with P. kluyveri and H. uvarum (Pk-Hu), had high residual sugar, sugar/acid ratio, and glucose-fructose consumption ratio. Large shifts in the consumption and production of organic acids and polyphenols among all ciders were observed. The calculation of the relative odor activity value (rOAV) showed that 17 volatile compounds had an rOAV >1 in at least one sample, and acetate esters and ethyl esters were the groups with the highest number of volatile compounds of importance to the cider aroma. Among these 17 compounds, 3-methylbutyl acetate, 2-methylbutyl acetate, ethyl hexanoate, ethyl octanoate, and β-damascenone exhibited high rOAVs in some ciders and might contribute fruity, floral, and sweet features to the cider aroma. Besides, the tropical fruity aroma from 3-methylbutyl acetate was only perceived in Pk and Pk-Hu. The partial least squares regression (PLSR) analysis revealed that acetate esters contributed positively to the roasted and cooked odor of all ciders. This is the first study evaluating simultaneous fermentation of two non-Saccharomyces yeasts to produce cider, which provides new insights into cider production.

The Effect of Different Starter Cultures of Lactobacillus paracasei M104 and Pediococcus pentosaceus M103 on the Physicochemical and Microbial Qualities of Fermented Goat Milk

The utilization of starter cultures is vital for dairy fermentation industries. Lactobacillus paracasei M104 and Pediococcus pentosaceus M103 have been isolated from goat milk and were demonstrated to acidify goat milk during fermentation. This study was conducted to compare the physicochemical and microbial qualities of goat milk fermented using these starter cultures either as a single starter or combined in goat milk. The treatments were L. paracasei M104 (Lp) and P. pentosaceus M103 (Pp) as single starter culture fermentation and combined (Lp/Pp) fermentation at a ratio of 1:1 at 6% inoculation (v/v). For control treatment, goat milk was fermented using yogurt starter, i.e., a combination culture of Streptococcus thermophilus and L. bulgaricus (St/Lb) at a ratio of 1:1 at 6% (v/v). The fermentation was performed by incubating the inoculated goat milk at 37°C for 18 h. The pH and degree of acidity were measured every 2 h during the fermentation process, whereas the physicochemical (pH, degree of acidity, lactose, protein, and viscosity) and microbial (total lactic acid bacteria/LAB) qualities were measured after the fermentation process. Data analysis revealed that the different starter cultures had no significant effect (P > 0.05) on the pH and degree of acidity, lactose and protein content, viscosity, and total LAB content. The goat milk fermented in this study had an average pH of 4.41 ± 0.11 and a degree of acidity of 1.26 ± 0.05%, a lactose content of 5.47± 0.80%, a protein content of 6.69± 1.52%, a viscosity of 1217 ± 395 cP, and a total LAB content of 9.57 ± 1.49 log CFU/mL. In conclusion, goat milk fermented using both single and combined starter cultures of L. paracasei M104 and P. pentosaceus M103 exhibited similar physicochemical and microbial qualities and required longer fermentation time compared with the control.

The Effect of Mixed Culture of <i>Zymomonas</i> <i>mobilis</i> and <i>Pichia stipitis</i> in Ethanol Production of Sugar Palm (<i>Arenga pinnata</i>)

In this study the effect of mixed culture of Zymomonasmobilis and Pichia stipitis to produce bioethanol from Solid Waste Arenga pinnata (SWAP) was investigated. The fermentation liquid substrate was resulted from an integrated process of pretreatment and enzymatic hydrolysis. Combination of diluted acid and ethanol organosolv pretreatment was used to increase the SWAP lignin removal. Raw pretreatment was used to decrease the SWAP particle size to 200 mesh. Acid pretreatment was done using 5% (v/v) diluted sulfate acid. Acid pretreated SWAP was treated for 65 min with organosolv pretreatment. Enzymatic hydrolysis by a combination of cellulase and xylanase was done for 48 h to convert cellulose into reducing sugar. The surfactants (Tween 80) addition was done to increase the sugar yield of the hydrolysis process. Fermentation variable consist of single culture of Z. mobilis as the control and mixed culture of Z. mobilis and P. stipitis, the microorganisms used to convert glucose and xylose into ethanol. The number of inoculum used in this experiment was more than 1.4 billion cells and the duration of fermentation process was 72 h. The delignification process decreased 95.43% lignin in SWAP. X-ray Diffraction (XRD) analysis assay showed an increase of crystallinity index of SWAP with pretreatment combination to 37.87%. Enzymatic hydrolysis by a combination of cellulase and xylanase with the addition of Tween 80 produced 9.16 gr glucose/L reducing sugar concentration. The highest ethanol resulted by fermentation process using mixed culture of Z. mobilis and P. stipitis with 0.33% (v/v) ethanol concentration and 0.57 (g ethanol/g reducing sugar) ethanol yield. Fermentation process using single culture Z. mobilis resulted 0.28% (v/v) ethanol concentration, and 0.48 (g ethanol/g reducing sugar) ethanol yield. The mixed culture fermentation with Z. mobilis and P. stipitis resulted ethanol yield 19 % higher than the single culture fermentation using Z. mobilis.

Comparative influence of salinity and temperature on cassava flour product by Lactobacillus plantarum and Lactobacillus acidophilus during single culture fermentation

Abstract. Frediansyah A, Kurniadi M. 2016. Comparative influence of salinity and temperature on cassava flour product by Lactobacillus plantarum and Lactobacillus acidophilus during single culture fermentation. Nusantara Bioscience 8: 207-214. Lactobacillus plantarum (FNCC 0027) and Lactobacillus acidophilus (FNCC 0051) were used as a single culture in cassava fermentation. The effect of salinity (0.5, 1, 2 and 3% (v/v)) and temperatures (4, 25, 30 and 40oC) were investigated on the survival of these lactobacilli. In addition, fiber and moisture content were used to study the characteristic of cassava flour as a final product. About 6.98 cfu/g of L. plantarum and 7.02 cfu/g of L acidophilus were used as a single starter (t = 0 h) for cassava fermentation. After 15 h, the survival rate of both lactobacilli with the salinity of 0.5% and incubation at 40oC were found to be at the highest compared with others. The temperature of incubation was showed in a degree-dependent manner in both reductions of pH to the substrate and fiber contents of flour product. However, it increased the survival of both L. plantarum and L. acidophilus in a degree of temperature-dependent manner. Both salinity and temperature did not give significant effect to further changing of moisture content. The fermentation of cassava could improve proximate composition, cyanide content and physical properties of cassava flour product.

Cell-to-cell contact and antimicrobial peptides play a combined role in the death of Lachanchea thermotolerans during mixed-culture alcoholic fermentation with Saccharomyces cerevisiae.

The roles of cell-to-cell contact and antimicrobial peptides in the early death of Lachanchea thermotolerans CBS2803 during anaerobic, mixed-culture fermentations with Saccharomyces cerevisiae S101 were investigated using a commercially available, double-compartment fermentation system separated by cellulose membranes with different pore sizes, i.e. 1000 kDa for mixed- and single-culture fermentations, and 1000 and 3.5-5 kDa for compartmentalized-culture fermentations. SDS-PAGE and gel filtration chromatography were used to determine an antimicrobial peptidic fraction in the fermentations. Our results showed comparable amounts of the antimicrobial peptidic fraction in the inner compartments of the mixed-culture and 1000 kDa compartmentalized-culture fermentations containing L. thermotolerans after 4 days of fermentation, but a lower death rate of L. thermotolerans in the 1000 kDa compartmentalized-culture fermentation than in the mixed-culture fermentation. Furthermore, L. thermotolerans died off even more slowly in the 3.5-5 kDa than in the 1000 kDa compartmentalized-culture fermentation, which coincided with the presence of less of the antimicrobial peptidic fraction in the inner compartment of that fermentation than of the 1000 kDa compartmentalized-culture fermentation. Taken together, these results indicate that the death of L. thermotolerans in mixed cultures with S. cerevisiae is caused by a combination of cell-to-cell contact and antimicrobial peptides.

Fermentation of Platycodi radix and bioconversion of platycosides using co-cultures of Saccharomyces cerevisiae KCTC 7928 and Aspergillus awamori FMB S900

Preparation of Platycodi radix (PR) wine and assessment of biotransformation patterns of PR platycosides using co-cultures of Saccharomyces cerevisiae KCTC 7928 with Aspergillus awamori FMB S900 were performed. The basal fermentation temperature was 15°C and a high sucrose concentration (30% and above) was used to increase the level of ethanol production. Fermentation of PR in co-cultures of S. cerevisiae with A. awamori was compared to single culture fermentations using S. cerevisiae at concentrations of 30–50% (w/w) sucrose with analysis at an interval of 15 days during fermentation. The 3 major saponins (platycoside E, platycodin D3, and platycodin D) were converted into 16-oxo-PD during co-cultures of S. cerevisiae with A. awamori with production of up to 12.5% ethanol (with an initial sugar concentration of 40%).

Fermentation and antimicrobial characteristics of Lactobacillus plantarum and Candida tropicalis from Nigerian fermented maize (akamu)

This study investigated the ability of Lactobacillus plantarum strains (NGL5 and NGL7) and Candida tropicalis (NGY1) previously identified from akamu -a Nigerian fermented maize food with probiotic L. plantarum LpTx and Saccharomyces boulardii SB20 to ferment ground maize slurries based on pH, acidity, microbial biomass, levels of sugars and organic acids, and their antimicrobial activity against Salmonella enterica serovar Enteritidis NCTC 5188, Escherichia coli NCTC 11560, Bacillus cereus NCIMB 11925, Staphylococcus aureus NCTC 3750 and Listeria monocytogenes NCTC 7973 using an agar spot assay. L. plantarum strains either as single or mixed starter cultures with the yeasts had growth rates ≥0.15 h -1 ,with pH significantly (p≤0.05) decreased to ≤3.93 after 12 h and then to ≤3.52 after 72 h and lactic acid >84 mmol L -1 . The yeasts had growth rates ≥0.18 h -1 but pH was ≥4.57 with lactic acid levels ≤20.23 mmol L -1 after 72 h in the single culture fermentation. There was no inhibition in modified MRS agar: 0.2% glucose and 0.2% glucose without Tween 80. Inhibition halos in MRS agar varied from 10.6 to 23.9 mm. S. bourladii was more inhibitory towards L. monocytogenes (8.6 mm) and B. cereus (5.4 mm ) than was C. tropicalis (1.1 and 3.3 mm for L. monocytogenes NCTC 7973 and B. cereus NCIMB 11925 respectively) (0.9 mm) in malt extract agar. This study showed that C. tropicalis was less inhibitory to the pathogens while antimicrobial activities of the L. plantarum strains were mainly due to acidity and the L. plantarum strains either as single or mixed cultures with the yeasts demonstrated strong fermentation ability, with significant decrease in pH which is vital in the choice of starter for product safety.

Fermentation and antimicrobial characteristics of Lactobacillus plantarum and Candida tropicalis from Nigerian fermented maize (akamu)

This study investigated the ability of Lactobacillus plantarum strains (NGL5 and NGL7) and Candida tropicalis (NGY1) previously identified from akamu-a Nigerian fermented maize food with probiotic L. plantarum LpTx and Saccharomyces boulardii SB20 to ferment ground maize slurries based on pH, acidity, microbial biomass, levels of sugars and organic acids, and their antimicrobial activity against Salmonella enterica serovar Enteritidis NCTC 5188, Escherichia coli NCTC 11560, Bacillus cereus NCIMB 11925, Staphylococcus aureus NCTC 3750 and Listeria monocytogenes NCTC 7973 using an agar spot assay. L. plantarum strains either as single or mixed starter cultures with the yeasts had growth rates ≥0.15 h-1,with pH significantly (p≤0.05) decreased to ≤3.93 after 12 h and then to ≤3.52 after 72 h and lactic acid >84 mmol L-1. The yeasts had growth rates ≥0.18 h-1 but pH was ≥4.57 with lactic acid levels ≤20.23 mmol L-1 after 72 h in the single culture fermentation. There was no inhibition in modified MRS agar: 0.2% glucose and 0.2% glucose without Tween 80. Inhibition halos in MRS agar varied from 10.6 to 23.9 mm. S. bourladii was more inhibitory towards L. monocytogenes (8.6 mm) and B. cereus (5.4 mm ) than was C. tropicalis (1.1 and 3.3 mm for L. monocytogenes NCTC 7973 and B. cereus NCIMB 11925 respectively) (0.9 mm) in malt extract agar. This study showed that C. tropicalis was less inhibitory to the pathogens while antimicrobial activities of the L. plantarum strains were mainly due to acidity and the L. plantarum strains either as single or mixed cultures with the yeasts demonstrated strong fermentation ability, with significant decrease in pH which is vital in the choice of starter for product safety.

Co-culture fermentation of peanut-soy milk for the development of a novel functional beverage

Most of the commercial probiotic products are dairy-based, and the development of non-dairy probiotic products could be an alternative for new functional products. The peanut-soy milk (PSM11PSM—peanut-soy milk.) was inoculated with six different lactic acid bacteria (LAB), including probiotic strains and yeasts and fermentation was accomplished for 24h at 37°C and afterwards, another 24h at ±4°C. The Pediococcus acidilactici (UFLA BFFCX 27.1), Lactococcus lactis (CCT 0360), Lactobacillus rhamnosus (LR 32) probiotic LAB, and the Lactobacillus delbrueckii subsp. bulgaricus (LB 340) yogurt starter culture reached cell concentrations of about 8.3logCFU/mL during fermentation. However, these strains were not able to acidify the substrate when inoculated as pure culture. The Lactobacillus acidophilus (LACA 4) probiotic produced significant amounts of lactic acid (3.35g/L) and rapidly lowered the pH (4.6). Saccharomyces cerevisiae (UFLA YFFBM 18.03) did not completely consume the available sugars in PSM and consequently produced low amounts of ethanol (0.24g/L). In pure culture, S. cerevisiae (UFLA YFFBM 18.03), L. rhamnosus (LR 32), L. acidophilus (LACA 4), and P. acidilactici (UFLA BFFCX 27.1) promoted the increase of total amino acids (48.02%, 47.32%, 46.21% and, 44.07%, respectively). However, when in co-cultured, the strains consumed the free amino acids favoring their growth, and reaching the population of 8logCFU/mL in PSM. Lactic acid production increased, and 12h was required to reach a pH value of 4.3. In general, the strains were more efficient in the use of available carbohydrates and release of metabolites in co-cultured than in single culture fermentations. An average of 58% and 78% of available carbohydrates was consumed when single and co-cultures were evaluated, respectively. Higher lactic acid contents were found in a binary culture of P. acidilactici (UFLA BFFCX 27.1) and L. acidophilus (LACA 4), and by co-culture of P. acidilactici (UFLA BFFCX 27.1), L. acidophilus (LACA 4) and S. cerevisiae (UFLA YFFBM 18.03) (9.03 and 8.51g/L, respectively). The final content of ethanol was 0.03% (v/v) or less, which classified the final beverage as non-alcoholic.