scholarly journals Interactions between Kazachstania humilis Yeast Species and Lactic Acid Bacteria in Sourdough

2020 ◽  
Vol 8 (2) ◽  
pp. 240 ◽  
Author(s):  
Belén Carbonetto ◽  
Thibault Nidelet ◽  
Stéphane Guezenec ◽  
Marc Perez ◽  
Diego Segond ◽  
...  

Sourdoughs harbor simple microbial communities usually composed of a few prevailing lactic acid bacteria species (LAB) and yeast species. However, yeast and LAB found in sourdough have been described as highly diverse. Even if LAB and yeast associations have been widely documented, the nature of the interactions between them has been poorly described. These interactions define the composition and structure of sourdough communities, and therefore, the characteristics of the final bread product. In this study, the nature of the interactions between strains of two commonly found sourdough yeast species, Kazachstania humilis and Saccharomyces cerevisiae, and lactic acid bacteria isolated from sourdoughs has been analyzed. Population density analysis showed no evidence of positive interactions, but instead revealed neutral or negative asymmetric interaction outcomes. When in coculture, the yeasts´ population size decreased in the presence of LAB regardless of the strain, while the LAB´s population size was rarely influenced by the presence of yeasts. However, a higher maltose depletion was shown in maltose-negative K. humilis and maltose-positive obligately heterofermentative LAB cocultures compared to monocultures. In addition, tested pairs of obligately heterofermentative LAB and K. humilis strains leavened dough as much as couples of LAB and S. cerevisiae strains, while K. humilis strains never leavened dough as much as S. cerevisiae when in monoculture. Taken together, our results demonstrate that even if higher fermentation levels with increased maltose depletion were detected for K. humilis and obligately heterofermentative LAB pairs, these interactions cannot be ecologically classified as positive, leading us to rethink the established hypothesis of coexistence by facilitation in sourdoughs.

2021 ◽  
Author(s):  
Lucas von Gastrow ◽  
Remy Amelot ◽  
Diego Segond ◽  
Stephane Guezennec ◽  
Florence Valence ◽  
...  

Understanding how microbes disperse in ecosystems is critical to understand the dynamics and evolution of microbial communities. However, microbial dispersal is difficult to study because of uncertainty about the vectors that may contribute to their migration. This applies to both microbial communities in natural and human-associated environments. Here, we studied microbial dispersal among French sourdoughs and flours used to make bread. Sourdough is a naturally fermented mixture of flour and water. It hosts a community of bacteria and yeasts whose origins are only partially known. We analyzed whether flour is a carrier of sourdough yeast and bacteria and studied whether microbial migration occurs between sourdoughs. The microbial community of a collection of 46 sourdough samples, as well as that of the flour from which each was made, was studied by 16S rDNA and ITS1 metabarcoding. No sourdough yeast species were detected in the flours. Sourdough lactic acid bacteria (LAB) were found in only five flour samples, and they did not have the same amplicon sequence variant (ASV) as found in the corresponding sourdough. The species shared between the sourdough and flour samples are commonly found on plants and are not known to be alive in sourdough. Thus, the flour microorganisms did not appear to grow in the sourdough microbial community. Dispersal between sourdoughs was also studied. Sourdoughs shared no yeast ASV, except in few cases where groups of three to five bakers shared some. These results suggest that there is little migration between sourdoughs, except in a few situations where bakers may exchange sourdough or be vectors of yeast dispersal themselves.


Author(s):  
Dea Korcari ◽  
Giovanni Ricci ◽  
Claudia Capusoni ◽  
Maria Grazia Fortina

AbstractIn this work we explored the potential of several strains of Kazachstania unispora to be used as non-conventional yeasts in sourdough fermentation. Properties such as carbohydrate source utilization, tolerance to different environmental factors and the performance in fermentation were evaluated. The K. unispora strains are characterized by rather restricted substrate utilization: only glucose and fructose supported the growth of the strains. However, the growth in presence of fructose was higher compared to a Saccharomyces cerevisiae commercial strain. Moreover, the inability to ferment maltose can be considered a positive characteristic in sourdoughs, where the yeasts can form a nutritional mutualism with maltose-positive Lactic Acid Bacteria. Tolerance assays showed that K. unispora strains are adapted to a sourdough environment: they were able to grow in conditions of high osmolarity, high acidity and in presence of organic acids, ethanol and salt. Finally, the performance in fermentation was comparable with the S. cerevisiae commercial strain. Moreover, the growth was more efficient, which is an advantage in obtaining the biomass in an industrial scale. Our data show that K. unispora strains have positive properties that should be explored further in bakery sector. Graphic abstract


1999 ◽  
Vol 62 (12) ◽  
pp. 1416-1429 ◽  
Author(s):  
J. MIGUEL ROCHA ◽  
F. XAVIER MALCATA

Traditional manufacture of bread from maize has been noted to play important roles from both economic and social standpoints; however, enforcement of increasingly strict hygiene standards requires thorough knowledge of the adventitious microbiota of the departing dough. To this goal, sourdough as well as maize and rye flours from several geographic locations and in two different periods within the agricultural year were assayed for their microbiota in sequential steps of quantification and identification. More than 400 strains were isolated and taxonomic differentiation between them was via Biomerieux API galleries (375 of which were successfully identified) following preliminary biochemical and morphological screening. The dominant groups were yeasts and lactic acid bacteria (LAB). The most frequently isolated yeasts were Saccharomyces cerevisiae and Candida pelliculosa. The most frequently isolated LAB were (heterofermentative) Leuconostoc spp. and (homo-fermentative) Lactobacillus spp.; L. brevis, L. curvatus, and L. lactis ssp. lactis were the dominant species for the Lactobacillus genera; Lactococcus lactis ssp. lactis for lactococci; Enterococcus casseliflavus, E. durans, and E. faecium for enterococci; and Streptococcus constellantus and S. equinus for streptococci.


Author(s):  
Oluwatosin Charles Ayodeji ◽  
Afolabi Folake Titilayo ◽  
Abdulkadir Musliu ◽  
Fasiku Oluwafemi

Malting is an important industrial product with a huge market outlet. Sorghum grain carries a numerous and variable, microbial population that mainly consists of bacteria, yeasts, and filamentous fungi. Sorghum malt is heavily reliant on chemical control of moulds and coliforms. This research aimed at investigating ways of improving malt quality and safety, using starter cultures of lactic acid bacteria and yeast, during the steeping stage of malting. All the steep treatments contained a sizeable population of moulds, greater than 4logcfu/mL, at 0hrs of steeping. A 3Log decrease was recorded in the steep treatment containing only single culture of Lactobacillus plantarum All the steeping treatments achieved varying levels of anti-nutrient reduction. The Lactobacillus plantarum CLB8 steep reduced the phytate level by as much as 47% when compared to the phytate level in sorghum grain. The combined cultures of Lactobacillus plantarum CLB8 and Saccharomyces cerevisiaeCYT1 reduced the phytate content by as much as 40% when compared to the sorghum grain without treatment. When compared to the control steep, the Lactobacillus plantarum CLB8 steep improved the anti-nutrient degradation by 31%. The combined cultures of Lactobacillus plantarum CLB8 and Saccharomyces cerevisiae CYT1 reduced the phytate content by as much as 23% when compared with the control steep. The polyphenol content was reduced by about 46% in the Lactobacillus plantarum CLB8 steep and 29% in the combined cultures of Lactobacillus plantarum CLB8 and Saccharomyces cerevisiae CYT1 steep when compared to the polyphenol content in the whole sorghum grain. Only the Lactobacillus plantarum CLB8 steep had better polyphenol reduction than the control with a 9.6% reduction more than the control. It was concluded that lactic acid bacteria can be apply as a biological control organism in malting of grains. 


Foods ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 156
Author(s):  
Dominika Jurášková ◽  
Susana C. Ribeiro ◽  
Celia C. G. Silva

The production of exopolysaccharides (EPS) by lactic acid bacteria (LAB) has attracted particular interest in the food industry. EPS can be considered as natural biothickeners as they are produced in situ by LAB and improve the rheological properties of fermented foods. Moreover, much research has been conducted on the beneficial effects of EPS produced by LAB on modulating the gut microbiome and promoting health. The EPS, which varies widely in composition and structure, may have diverse health effects, such as glycemic control, calcium and magnesium absorption, cholesterol-lowering, anticarcinogenic, immunomodulatory, and antioxidant effects. In this article, the latest advances on structure, biosynthesis, and physicochemical properties of LAB-derived EPS are described in detail. This is followed by a summary of up-to-date methods used to detect, characterize and elucidate the structure of EPS produced by LAB. In addition, current strategies on the use of LAB-produced EPS in food products have been discussed, focusing on beneficial applications in dairy products, gluten-free bakery products, and low-fat meat products, as they positively influence the consistency, stability, and quality of the final product. Highlighting is also placed on reports of health-promoting effects, with particular emphasis on prebiotic, immunomodulatory, antioxidant, cholesterol-lowering, anti-biofilm, antimicrobial, anticancer, and drug-delivery activities.


2019 ◽  
Vol 56 (9) ◽  
pp. 3969-3979
Author(s):  
Fernanda Corrêa Leal Penido ◽  
Carmen de Oliveira Goulart ◽  
Yara Cristina Fidelis Galvão ◽  
Carolina Vasconcelos Teixeira ◽  
Roseane Batitucci Passos de Oliveira ◽  
...  

2019 ◽  
Vol 20 (7) ◽  
pp. 1659
Author(s):  
Katarzyna Pielech-Przybylska ◽  
Maria Balcerek ◽  
Grzegorz Ciepielowski ◽  
Barbara Pacholczyk-Sienicka ◽  
Łukasz Albrecht ◽  
...  

The qualitative and quantitative composition of volatile compounds in fermented distillery mash determines the quality of the obtained distillate of agricultural origin (i.e., raw spirit) and the effectiveness of further purification steps. Propan-2-ol (syn. isopropyl alcohol), due to its low boiling point, is difficult to remove by rectification. Therefore, its synthesis needs to be limited during fermentation by Saccharomyces cerevisiae yeast, while at the same time controlling the levels of acetaldehyde and acetic acid, which are likewise known to determine the quality of raw spirit. Lactic acid bacteria (LAB) are a common but undesirable contaminant in distillery mashes. They are responsible for the production of undesirable compounds, which can affect synthesis of propan-2-ol. Some bacteria strains are able to synthesize isopropyl alcohol. This study therefore set out to investigate whether LAB with S. cerevisiae yeast are responsible for conversion of acetone to propan-2-ol, as well as the effects of the amount of LAB inoculum and fermentation parameters (pH and temperature) on the content of isopropyl alcohol, acetaldehyde, lactic acid and acetic acid in fermented mashes. The results of NMR and comprehensive two-dimensional gas chromatography coupled with time of flight mass spectrometry (GC × GC-TOF MS) analysis confirmed the ability of the yeast and LAB strains to metabolize acetone via its reduction to isopropyl alcohol. Efficient fermentation of distillery mashes was observed in all tested mashes with an initial LAB count of 3.34–6.34 log cfu/mL, which had no significant effect on the ethanol content. However, changes were observed in the contents of by-products. Lowering the initial pH of the mashes to 4.5, without and with LAB (3.34–4.34 log cfu/mL), resulted in a decrease in propan-2-ol and a concomitant increase in acetaldehyde content, while a higher pH (5.0 and 5.5) increased the content of propan-2-ol and decreased acetaldehyde content. Higher temperature (35 °C) promoted propan-2-ol synthesis and also resulted in increased acetic acid content in the fermented mashes compared to the controls. Moreover, the acetic acid content rose with increases in the initial pH and the initial LAB count.


2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Rudy Sutrisna ◽  
Christina Nugroho Ekowati ◽  
Riska Damayanti

This study aims to determine differences in the viability of Lactic Acid Bacteria (LAB) isolates on MRS medium supplemented with various concentrations molasses. Concentration variation molasis used as controls were 0%, 1%, 2% and 3%. Variation of time incubation on each of the media that is 0 hours, 24 hours, 48 hours and 72 hours. The viability of each isolate was viewed with the population of Log (cells/ml) which grow on the medium and the number of generations and time of generations. The results showed that the concentration molasses added to MRS affect the viability of LAB. Concentration of 1% makes LAB better viability than controls. Total population continues to increase at the end of the incubation with a yield of 1.17 generations in time 20.46 hours/generation. In contrast to controls, reduced population size at the end of the incubation so as not to produce a generation. LAB viability in addition molasses 2% and 3% live on 48 hours of incubation. This is indicated by the number of population increased at 48 hours of incubation, and then decreased at the end of incubation. The addition of concentration variation in the types of bacteria showed different viability. At B1 adding molasses 2% and 3% live on 48 hours of incubation and control can only live on a 24 hours incubation, whereas the B3, the control can remain alive at 48 hours of incubation. In contrast to the controls on B4 can survive on 48 hours of incubation, whereas the addition of 3% molasses can only live on a 24 hours incubation. Key words : Lactic Acid Bacteria/LAB, Molasses,  Viability


2020 ◽  
Vol 28 (4) ◽  
pp. 225-233
Author(s):  
Liliia Vasina ◽  
Ivanna Kraievska ◽  
Oleksii Khudyi ◽  
Lidiia Khuda ◽  
Larysa Cheban

Abstract Freshwater zooplankton, which is commonly used as a starting fish feed, has a low content of essential compounds such as carotenoids. The possibility of increasing the productivity of carotenogenic yeast, Rhodotorula glutinis, for further bioencapsulation of zooplankton Daphnia magna is shown. An association of a UV irradiated yeast strain with lactic acid bacteria was cultivated for this purpose. This permitted intensifying the carotenogenesis of yeast, and the content of â-carotene increased by 1.7 times, and that of torularodine by 2.3 times compared with the native monoculture. The use of the association of microorganisms as a feed substrate in the cultivation of Daphnia magna provided both an increase in the carotenoid content in the investigated crustaceans more than 8 times, and their biomass by 2.5 times compared with the standard feed of Saccharomyces cerevisiae.


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