scholarly journals Microbial Community Dynamics during Production of the Mexican Fermented Maize Dough Pozol

2000 ◽  
Vol 66 (9) ◽  
pp. 3664-3673 ◽  
Author(s):  
Nabil ben Omar ◽  
Fr�d�ric Ampe
Keyword(s):  
Lactic Acid ◽  
Microbial Community ◽  
Community Dynamics ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Culture Media ◽  
Polyphasic Approach ◽  
Close Relative ◽  
Fermented Foods ◽  
Fermentation Products ◽  
Rdna Genes

ABSTRACT The dynamics of the microbial community responsible for the traditional fermentation of maize in the production of Mexican pozol was investigated by using a polyphasic approach combining (i) microbial enumerations with culture media, (ii) denaturing gradient gel electrophoresis (DGGE) fingerprinting of total community DNA with bacterial and eukaryotic primers and sequencing of partial 16S ribosomal DNA (rDNA) genes, (iii) quantification of rRNAs from dominant microbial taxa by using phylogenetic oligonucleotide probes, and (iv) analysis of sugars and fermentation products. AStreptococcus species dominated the fermentation and accounted for between 25 and 75% of the total flora throughout the process. Results also showed that the initial epiphytic aerobic microflora was replaced in the first 2 days by heterofermentative lactic acid bacteria (LAB), including a close relative ofLactobacillus fermentum, producing lactic acid and ethanol; this heterolactic flora was then progressively replaced by homofermentative LAB (mainly close relatives of L. plantarum, L. casei, and L. delbrueckii) which continued acidification of the maize dough. At the same time, a very diverse community of yeasts and fungi developed, mainly at the periphery of the dough. The analysis of the DGGE patterns obtained with bacterial and eukaryotic primers targeting the 16S and 18S rDNA genes clearly demonstrated that there was a major shift in the community structure after 24 h and that high biodiversity—according to the Shannon-Weaver index—was maintained throughout the process. These results proved that a relatively high number of species, at least six to eight, are needed to perform this traditional lactic acid fermentation. The presence ofBifidobacterium, Enterococcus, and enterobacteria suggests a fecal origin of some important pozol microorganisms. Overall, the results obtained with different culture-dependent or -independent techniques clearly confirmed the importance of developing a polyphasic approach to study the ecology of fermented foods.

scholarly journals Polyphasic Study of the Spatial Distribution of Microorganisms in Mexican Pozol, a Fermented Maize Dough, Demonstrates the Need for Cultivation-Independent Methods To Investigate Traditional Fermentations

1999 ◽  
Vol 65 (12) ◽  
pp. 5464-5473 ◽  
Author(s):  
Frédéric Ampe ◽  
Nabil ben Omar ◽  
Claire Moizan ◽  
Carmen Wacher ◽  
Jean-Pierre Guyot
Keyword(s):  
Lactic Acid ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Fermented Food ◽  
Fermented Foods ◽  
Product Analysis ◽  
Culture Independent ◽  
Gradient Gel Electrophoresis ◽  
Traditional Fermented Foods

ABSTRACT The distribution of microorganisms in pozol balls, a fermented maize dough, was investigated by a polyphasic approach in which we used both culture-dependent and culture-independent methods, including microbial enumeration, fermentation product analysis, quantification of microbial taxa with 16S rRNA-targeted oligonucleotide probes, determination of microbial fingerprints by denaturing gradient gel electrophoresis (DGGE), and 16S ribosomal DNA gene sequencing. Our results demonstrate that DGGE fingerprinting and rRNA quantification should allow workers to precisely and rapidly characterize the microbial assemblage in a spontaneous lactic acid fermented food. Lactic acid bacteria (LAB) accounted for 90 to 97% of the total active microflora; no streptococci were isolated, although members of the genus Streptococcus accounted for 25 to 50% of the microflora. Lactobacillus plantarum and Lactobacillus fermentum, together with members of the generaLeuconostoc and Weissella, were the other dominant organisms. The overall activity was more important at the periphery of a ball, where eucaryotes, enterobacteria, and bacterial exopolysacharide producers developed. Our results also showed that the metabolism of heterofermentative LAB was influenced in situ by the distribution of the LAB in the pozol ball, whereas homolactic fermentation was controlled primarily by sugar limitation. We propose that starch is first degraded by amylases from LAB and that the resulting sugars, together with the lactate produced, allow a secondary flora to develop in the presence of oxygen. Our results strongly suggest that cultivation-independent methods should be used to study traditional fermented foods.

scholarly journals Citrate and malonate increase microbial activity and alter microbial community composition in uncontaminated and diesel-contaminated soil microcosms

SOIL ◽  
2016 ◽  
Vol 2 (3) ◽  
pp. 487-498 ◽  
Author(s):  
Belinda C. Martin ◽  
Suman J. George ◽  
Charles A. Price ◽  
Esmaeil Shahsavari ◽  
Andrew S. Ball ◽  
...  
Keyword(s):  
Microbial Community ◽  
Microbial Activity ◽  
Community Dynamics ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Plant Root ◽  
Root Exudation ◽  
Microbial Community Composition ◽  
Gas Chromatography Mass Spectrometry ◽  
Potential Implication ◽  
Microbial Community Dynamics

Abstract. Petroleum hydrocarbons (PHCs) are among the most prevalent sources of environmental contamination. It has been hypothesized that plant root exudation of low molecular weight organic acid anions (carboxylates) may aid degradation of PHCs by stimulating heterotrophic microbial activity. To test their potential implication for bioremediation, we applied two commonly exuded carboxylates (citrate and malonate) to uncontaminated and diesel-contaminated microcosms (10 000 mg kg−1; aged 40 days) and determined their impact on the microbial community and PHC degradation. Every 48 h for 18 days, soil received 5 µmol g−1 of (i) citrate, (ii) malonate, (iii) citrate + malonate or (iv) water. Microbial activity was measured daily as the flux of CO2. After 18 days, changes in the microbial community were assessed by a community-level physiological profile (CLPP) and 16S rRNA bacterial community profiles determined by denaturing gradient gel electrophoresis (DGGE). Saturated PHCs remaining in the soil were assessed by gas chromatography–mass spectrometry (GC-MS). Cumulative soil respiration increased 4- to 6-fold with the addition of carboxylates, while diesel contamination resulted in a small, but similar, increase across all carboxylate treatments. The addition of carboxylates resulted in distinct changes to the microbial community in both contaminated and uncontaminated soils but only a small increase in the biodegradation of saturated PHCs as measured by the n-C17 : pristane biomarker. We conclude that while the addition of citrate and malonate had little direct effect on the biodegradation of saturated hydrocarbons present in diesel, their effect on the microbial community leads us to suggest further studies using a variety of soils and organic acids, and linked to in situ studies of plants, to investigate the role of carboxylates in microbial community dynamics.

scholarly journals Potential of Lactic Acid Bacteria From Tape and Jember Tempeh as a Probiotic Candidate

2021 ◽  
Vol 6 (2) ◽  
pp. 273-283
Author(s):  
Siti Nur Azizah ◽  
Mikhania Christiningtyas Eryani ◽  
Azizah Azizah
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bile Salts ◽  
Gastric Ph ◽  
Diffusion Method ◽  
Fermented Foods ◽  
Test Results ◽  
Fermentation Products ◽  
E Coli ◽  
Beneficial Effects

Probiotics are microbes in fermented foods that have beneficial effects on health. Microbes that act as probiotics are lactic acid bacteria (LAB) that can produce metabolites such as lactic acid, hydrogen peroxide, and bacteriocins. This study aimed to obtain lactic acid bacterial isolates from tape and tempeh, and to test the potential of LAB as a probiotic candidate by activity test as an antidiarrhea and its resistance to gastric pH and bile salts. The fermentation products used as a source of LAB isolates are tempeh sumber mas merk, and yellow cassava tape, sari madu merk from Jember. The results of the first stage regarding the isolation of LAB using GYP media showed that there were 2 LAB isolates (TaJ.14 and TaJ.15) from the tape and 4 LAB isolates (TeJ.18, TeJ.22, TeJ.24, and TeJ.25) from tempeh. The results of the antidiarrheal test using the disc diffusion method (oxoid) showed that TaJ.14 and TaJ.15 isolates were able to inhibit Bacillus subtilis, Escherichia coli, and Shigella dysentriae, while TeJ.18, TeJ.22, TeJ.24, TeJ.25, and Lactobacillus casei (control) was only able to inhibit B. subtilis and E. coli. The results of LAB resistance to gastric pH showed that the TeJ.25 isolate had the highest percentage of pH 3 and 2.5 resistance (51.13 and 33.03%) compared to other isolates and controls. LAB resistance test results against bile salts (oxgal) showed that the TeJ.22 isolate had the highest percentage of resistance (75.10%) compared to other isolates although was still higher in control (75.99%).

scholarly journals Physicochemical and biological dynamics in a coastal Antarctic lake as it transitions from frozen to open water

2013 ◽  
Vol 25 (5) ◽  
pp. 663-675 ◽  
Author(s):  
Markus Dieser ◽  
Christine M. Foreman ◽  
Christopher Jaros ◽  
John T. Lisle ◽  
Mark Greenwood ◽  
...  
Keyword(s):  
Microbial Community ◽  
Physicochemical Parameters ◽  
Community Dynamics ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Community Composition ◽  
Late Summer ◽  
Open Water ◽  
Rrna Gene ◽  
Coastal Lake ◽  
16S Rrna Gene Analysis

AbstractPony Lake, at Cape Royds, Antarctica, is a shallow, eutrophic, coastal lake that freezes solid in the winter. Changes in Pony Lake's physicochemical parameters and microbial community were studied during the transition from ice to open water. Due to rising water temperatures, the progressive melt of the ice column and the gradual mixing of basal brines into the remaining water column, Pony Lake evolved physically and chemically over the course of the summer, thereby affecting the microbial community composition. Temperature, pH, conductivity, nutrients and major ion concentrations reached their maximum in January. Pony Lake was colonized by bacteria, viruses, phytoflagellates, ciliates, and a small number of rotifers. Primary and bacterial production were highest in mid-December (2.66 mg C l-1d-1and 30.5 μg C l-1d-1, respectively). A 16S rRNA gene analysis of the bacterioplankton revealed 34 unique sequences dominated by members of theβ- andγ-proteobacterialineages. Cluster analyses on denaturing gradient gel electrophoresis (DGGE) banding patterns and community structure indicated a shift in the dominant members of the microbial community during the transition from winter ice, to early, and late summer lakewater. Our data demonstrate that temporal changes in physicochemical parameters during the summer months determine community dynamics and mediate changes in microbial species composition.

Microbial community structure and performance of an anaerobic reactor digesting cassava pulp and pig manure

2012 ◽  
Vol 66 (7) ◽  
pp. 1590-1600 ◽  
Author(s):  
P. Panichnumsin ◽  
B. Ahring ◽  
A. Nopharatana ◽  
P. Chaiprasert
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Community Dynamics ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Pig Manure ◽  
Relative Distribution ◽  
Cassava Pulp ◽  
Microbial Community Dynamics ◽  
Gradient Gel Electrophoresis ◽  
Substrate Types

Microbial community dynamics in response to changes in substrate types (i.e. pig manure (PM), cassava pulp (CP) and mixtures of PM and CP) were investigated in an anaerobic continuously stirred tank reactor (CSTR). Molecular identification of bacterial and archaeal domains were performed, using a 16S rDNA clone library with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) screening and phylogenetic analysis. Analysis of bacterial clone libraries revealed that the differences in the community structure corresponded to the substrate types. However, the Bacteroidetes were the most abundant group in all substrates, followed by the Clostridia. With pure PM, the dominant bacterial groups were Bacteroidales, Clostridia and Paludibacter. With a co-substrate, at CP to PM (CP:PM) ratio of 50:50, the sequences analysis revealed the greatest diversity of bacterial communities at class level, and the sequences affiliated with Cytophaga sp. became an exclusive predominant. With CP alone, Bacteroides sp. was the dominant species and this reactor had the lowest diversity of bacteria. Archaea observed in the CSTR fed with all substrate types were Methanosaeta sp., Methanosaeta concilii and Methanospirillum hungatei. Among the Archaea, Methanosaeta sp. was the exclusive predominant. The relative distribution of Archaea also changed regarding to the substrate types.

scholarly journals Effect of Nutrient Periodicity on Microbial Community Dynamics

2006 ◽  
Vol 72 (5) ◽  
pp. 3175-3183 ◽  
Author(s):  
Militza Carrero-Col�n ◽  
Cindy H. Nakatsu ◽  
Allan Konopka
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Growth Rates ◽  
Community Dynamics ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Pulse Interval ◽  
Substrate Affinity ◽  
Rrna Gene ◽  
Similarity Coefficients ◽  
Microbial Community Dynamics

ABSTRACT When microbes are subjected to temporal changes in nutrient availability, growth rate and substrate affinity can contribute to competitive fitness and thereby affect microbial community structure. This hypothesis was tested using planktonic bacterial communities exposed to nutrient additions at 1-, 3-, 7-, or 14-day intervals. Growth rates after nutrient addition were inversely proportional to the pulse interval and declined from 0.5 h−1 to 0.15 h−1 as the pulse interval increased from 1 to 14 days. The dynamics of community structure were monitored by 16S rRNA gene PCR-denaturing gradient gel electrophoresis. At pulse intervals of more than 1 day, the community composition continued to change over 130 days. Although replicate systems exposed to the same pulse interval were physiologically similar, their community compositions could exhibit as much dissimilarity (Dice similarity coefficients of <0.5) as did systems operated at different intervals. Bacteria were cultivated from the systems to determine if the physiological characteristics of individual members were consistent with the measured performance of the systems. The isolates fell into three bacterial divisions, Bacteroidetes, Proteobacteria, and Actinobacteria. In agreement with community results, bacteria isolated from systems pulsed every day with nutrients had higher growth rates and ectoaminopeptidase specific activities than isolates from systems pulsed every 14 days. However, the latter isolates did not survive starvation longer than those provided with nutrients every day. The present study demonstrates the dynamic nature of microbial communities exposed to even simple and regular environmental discontinuities when a substantial pool of species that can catabolize the limiting substrate is present.

scholarly journals Drivers of human gut microbial community assembly: Coadaptation, determinism and stochasticity

2018 ◽  
Author(s):  
Kaitlyn Oliphant ◽  
Valeria R. Parreira ◽  
Kyla Cochrane ◽  
Emma Allen-Vercoe
Keyword(s):  
Microbial Community ◽  
Community Assembly ◽  
Community Dynamics ◽  
Marker Gene ◽  
Species Structure ◽  
Design Strategies ◽  
Habitat Filtering ◽  
Fermentation Products ◽  
High Fiber ◽  
Microbial Community Assembly

AbstractMicrobial community assembly is a complex process shaped by multiple factors, including habitat filtering, species assortment and stochasticity. Understanding the relative importance of these drivers would enable scientists to design strategies initiating a desired reassembly for e.g., remediating low diversity ecosystems. Here, we aimed to examine if a human fecal-derived defined microbial community cultured in bioreactors assembled deterministically or stochastically, by completing replicate experiments under two growth medium conditions characteristic of either high fiber or high protein diets. Then, we recreated this defined microbial community by matching different strains of the same species sourced from distinct human donors, in order to elucidate whether coadaptation of strains within a host influenced community dynamics. Each defined microbial ecosystem was evaluated for composition using marker gene sequencing, and for behaviour using 1H-NMR based metabonomics. We found that stochasticity had the largest influence on the species structure when substrate concentrations varied, whereas habitat filtering greatly impacted the metabonomic output. Evidence of coadaptation was elucidated from comparisons of the two communities; we found that the artificial community tended to exclude saccharolytic Firmicutes species and was enriched for metabolic intermediates, such as Stickland fermentation products, suggesting overall that polysaccharide utilization by Firmicutes is dependent on cooperation.

scholarly journals Inhibiting Methanogenesis in Rumen Batch Cultures Did Not Increase the Recovery of Metabolic Hydrogen in Microbial Amino Acids

2019 ◽  
Vol 7 (5) ◽  
pp. 115 ◽  
Author(s):  
Emilio M. Ungerfeld ◽  
M. Fernanda Aedo ◽  
Emilio D. Martínez ◽  
Marcelo Saldivia
Keyword(s):  
Amino Acids ◽  
Energy Efficiency ◽  
Microbial Community ◽  
Gel Electrophoresis ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Community Composition ◽  
Fermentation Products ◽  
Batch Cultures ◽  
Gradient Gel Electrophoresis

There is an interest in controlling rumen methanogenesis as an opportunity to both decrease the emissions of greenhouse gases and improve the energy efficiency of rumen fermentation. However, the effects of inhibiting rumen methanogenesis on fermentation are incompletely understood even in in vitro rumen cultures, as the recovery of metabolic hydrogen ([H]) in the main fermentation products consistently decreases with methanogenesis inhibition, evidencing the existence of unaccounted [H] sinks. We hypothesized that inhibiting methanogenesis in rumen batch cultures would redirect [H] towards microbial amino acids (AA) biosynthesis as an alternative [H] sink to methane (CH4). The objective of this experiment was to evaluate the effects of eight inhibitors of methanogenesis on digestion, fermentation and the production of microbial biomass and AA in rumen batch cultures growing on cellulose. Changes in the microbial community composition were also studied using denaturing gradient gel electrophoresis (DGGE). Inhibiting methanogenesis did not cause consistent changes in fermentation or the profile of AA, although the effects caused by the different inhibitors generally associated with the changes in the microbial community that they induced. Under the conditions of this experiment, inhibiting methanogenesis did not increase the importance of microbial AA synthesis as a [H] sink.

Sign in / Sign up

Export Citation Format

Share Document