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International Journal of Environmental... Mar 2023The main goal of wastewater treatment is to significantly reduce organic compounds, micronutrients (nitrogen and phosphorus) and heavy metals and other contaminants...
The main goal of wastewater treatment is to significantly reduce organic compounds, micronutrients (nitrogen and phosphorus) and heavy metals and other contaminants (pathogens, pharmaceuticals and industrial chemicals). In this work, the efficiency of removing different contaminants (COD, NO, NO, NH, PO, SO, Pb, Cd) from synthetic wastewater was tested using five different yeast strains: CMGBP16 (P1), S228C (P2), CM6B70 (P3), CMGB234 (P4) and CMGB88 (P5). The results showed a removal efficiency of up to 70% of COD, 97% of nitrate, 80% of nitrite, 93% of phosphate and 70% of sulfate ions for synthetic wastewater contaminated with Pb (43 mg/L) and Cd ions (39 mg/L). In contrast, the results showed an increase in ammonium ions, especially in the presence of Pb ions. The yeast strains showed a high capacity to reduce Pb (up to 96%) and Cd (up to 40%) ions compared to the initial concentrations. In presence of a crude biosurfactant, the removal efficiency increased up to 99% for Pb and 56% for Cd simultaneously with an increase in yeast biomass of up to 11 times. The results, which were obtained in the absence of aeration and in neutral pH conditions, proved a high potential for practical applications in the biotreatment of the wastewater and the recovery of Pb and Cd ions, with a high benefit-cost ratio.
Topics: Wastewater; Saccharomyces cerevisiae; Cadmium; Biodegradation, Environmental; Lead; Metals, Heavy; Phosphates
PubMed: 36981703
DOI: 10.3390/ijerph20064795 -
Heliyon May 2024The growing amount of plastic waste requires new ways of disposal or recycling. Research into the biodegradation of recalcitrant plastic polymers is gathering pace....
The growing amount of plastic waste requires new ways of disposal or recycling. Research into the biodegradation of recalcitrant plastic polymers is gathering pace. Despite some progress, these efforts have not yet led to technologically and economically viable applications. In this study, we show that respirometric screening of environmental fungal isolates in combination with scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy can be used to identify new strains with the potential for the degradation of plastic polymers. We screened 146 fungal strains, 71 isolated from car repair shops, an environment rich in long-chain hydrocarbons, and 75 isolated from hypersaline water capable of growing at high concentrations of NaCl. When grown in a minimal medium with no carbon source, some strains produced significantly more CO when a pure plastic polymer was added to the medium, some only at high salinity. A selection of these strains was shown by FTIR and Raman spectroscopy to alter the properties of plastic polymers: sp. EXF-13502 on polyamide, EXF-13500 on polypropylene, sp. EXF-10630 on low-density polyethylene and EXF-6848 on polyethylene terephthalate. Respirometry in combination with specific spectroscopic methods is an efficient method for screening microorganisms capable of at least partial plastic degradation and can be used to expand the repertoire of potential plastic degraders. This is of particular importance as our results also show that individual strains are only active against certain polymers and under certain conditions. Therefore, efficient biodegradation of plastics is likely to depend on a collection of specialized microorganisms rather than a single universal plastic degrader.
PubMed: 38803974
DOI: 10.1016/j.heliyon.2024.e31130 -
Microorganisms Sep 2019This experiment was carried out to identify and select pectinolytic yeasts that have potential use as a starter culture for coffee fermentation during wet processing....
This experiment was carried out to identify and select pectinolytic yeasts that have potential use as a starter culture for coffee fermentation during wet processing. The coffee fruit was fermented for 48 h at 28 °C and a sample was taken from the fermented solution and spread onto yeast extract-peptone-dextrose agar (YPDA) media and incubated at 28 °C. A total of 28 yeasts were isolated, eight of which had the ability to produce pectinase enzymes. The species of those eight yeasts were molecularly identified and confirmed. These yeasts are (strain KNU18Y3), (strain KNU18Y4), (strain KNU18Y5 and KNU18Y6) (strain KNU18Y7 and KNU18Y8), and (strain KNU18Y12 and KNU18Y13). The pectin degradation index of (strain KNU18Y4), (strain KNU18Y3), and (strain KNU18Y6) were higher compared to the others, at 178%, 160%, and 152%, respectively. The pectinase enzyme assays were made on two growth media: coffee pulp media (CPM) and synthetic pectin media (SPM). (strain KNU18Y4) and (strain KNU18Y3) had great potential in producing polygalacturonase (PG) and pectin lyase (PL) compared to others in both media. However, strains (KNU18Y12 and KNU18Y13) produced higher pectin methylesterase (PME). Using MEGA 6 software, the phylogenetic trees were constructed to determine the evolutionary relationship of newly identified yeasts from our experiment and previously published yeast species. The sequences of the yeasts were deposited in the National Center for Biotechnology Information (NCBI) database.
PubMed: 31569406
DOI: 10.3390/microorganisms7100401 -
Frontiers in Microbiology 2022The aim of this study was to investigate the influence of , alone or in combination with a214 or citric acid, on forage oat silage quality, bacterial and fungal...
The aim of this study was to investigate the influence of , alone or in combination with a214 or citric acid, on forage oat silage quality, bacterial and fungal microbiological profile during ensiling and aerobic exposure. With the exception of , all additives could improve silage quality of forage oat based on lower ammonia-nitrogen content and higher residual of water soluble carbohydrates during anaerobic fermentation compared to control silage, especially in combined with citric acid (CAPF). was the dominant bacteria in all silages, while CAPF group increased the relative abundance of and compared to control silage. The application of suppressed the relative abundance of yeasts such as and in response to aerobic exposure, especially in CAPF treatment, leading to high acetic acids and lower dry matter loss, as well as good aerobic stability. Therefore, , alone or in combination with citric acid, has potential to improve aerobic stability of forage oat silage by shifting bacterial and fungal community composition, and can be used as new additive to prepare high-quality silage for animal production.
PubMed: 36605512
DOI: 10.3389/fmicb.2022.1053933 -
Scientific Reports Oct 2022Due to the co-evolved intricate relationships and mutual influence between changes in the microbiome and silage fermentation quality, we explored the effects of...
Due to the co-evolved intricate relationships and mutual influence between changes in the microbiome and silage fermentation quality, we explored the effects of Lactobacillus plantarum and Propionibacterium acidipropionici (Inoc1) or Lactobacillus buchneri (Inoc2) inoculants on the diversity and bacterial and fungal community succession of rehydrated corn (CG) and sorghum (SG) grains and their silages using Illumina Miseq sequencing after 0, 3, 7, 21, 90, and 360 days of fermentation. The effects of inoculants on bacterial and fungal succession differed among the grains. Lactobacillus and Weissella species were the main bacteria involved in the fermentation of rehydrated corn and sorghum grain silage. Aspergillus spp. mold was predominant in rehydrated CG fermentation, while the yeast Wickerhamomyces anomalus was the major fungus in rehydrated SG silages. The Inoc1 was more efficient than CTRL and Inoc2 in promoting the sharp growth of Lactobacillus spp. and maintaining the stability of the bacterial community during long periods of storage in both grain silages. However, the bacterial and fungal communities of rehydrated corn and sorghum grain silages did not remain stable after 360 days of storage.
Topics: Agricultural Inoculants; Edible Grain; Fermentation; Microbiota; Silage; Sorghum; Zea mays
PubMed: 36207495
DOI: 10.1038/s41598-022-21461-4 -
Biotechnology For Biofuels Oct 2021Ethyl acetate (CHO) and hydrogen (H) are industrially relevant compounds that preferably are produced via sustainable, non-petrochemical production processes. Both...
BACKGROUND
Ethyl acetate (CHO) and hydrogen (H) are industrially relevant compounds that preferably are produced via sustainable, non-petrochemical production processes. Both compounds are volatile and can be produced by Escherichia coli before. However, relatively low yields for hydrogen are obtained and a mix of by-products renders the sole production of hydrogen by micro-organisms unfeasible. High yields for ethyl acetate have been achieved, but accumulation of formate remained an undesired but inevitable obstacle. Coupling ethyl acetate production to the conversion of formate into H may offer an interesting solution to both drawbacks. Ethyl acetate production requires equimolar amounts of ethanol and acetyl-CoA, which enables a redox neutral fermentation, without the need for production of by-products, other than hydrogen and CO.
RESULTS
We engineered Escherichia coli towards improved conversion of formate into H and CO by inactivating the formate hydrogen lyase repressor (hycA), both uptake hydrogenases (hyaAB, hybBC) and/or overexpressing the hydrogen formate lyase activator (fhlA), in an acetate kinase (ackA) and lactate dehydrogenase (ldhA)-deficient background strain. Initially 10 strains, with increasing number of modifications were evaluated in anaerobic serum bottles with respect to growth. Four reference strains ΔldhAΔackA, ΔldhAΔackA p3-fhlA, ΔldhAΔackAΔhycAΔhyaABΔhybBC and ΔldhAΔackAΔhycAΔhyaABΔhybBC p3-fhlA were further equipped with a plasmid carrying the heterologous ethanol acyltransferase (Eat1) from Wickerhamomyces anomalus and analyzed with respect to their ethyl acetate and hydrogen co-production capacity. Anaerobic co-production of hydrogen and ethyl acetate via Eat1 was achieved in 1.5-L pH-controlled bioreactors. The cultivation was performed at 30 °C in modified M9 medium with glucose as the sole carbon source. Anaerobic conditions and gas stripping were established by supplying N gas.
CONCLUSIONS
We showed that the engineered strains co-produced ethyl acetate and hydrogen to yields exceeding 70% of the pathway maximum for ethyl acetate and hydrogen, and propose in situ product removal via gas stripping as efficient technique to isolate the products of interest.
PubMed: 34598726
DOI: 10.1186/s13068-021-02036-3 -
Frontiers in Microbiology 2023It is shown that bacteria use yeast as a niche for survival in stressful conditions, therefore yeasts may act as temporary or permanent bacterial reservoirs....
It is shown that bacteria use yeast as a niche for survival in stressful conditions, therefore yeasts may act as temporary or permanent bacterial reservoirs. Endobacteria colonise the fungal vacuole of various osmotolerant yeasts which survive and multiply in sugar-rich sources such as plant nectars. Nectar-associated yeasts are present even in the digestive system of insects and often establish mutualistic symbioses with both hosts. Research on insect microbial symbioses is increasing but bacterial-fungal interactions are yet unexplored. Here, we have focused on the endobacteria of (formerly and ), an osmotolerant yeast associated with sugar sources and the insect gut Symbiotic strains of influence larval development and contribute digestive processes in adults, in addition to exerting wide antimicrobial properties for host defence in diverse insects including mosquitoes. Antiplasmodial effects of have been shown in the gut of the female malaria vector mosquito . This discovery highlights the potential of utilizing yeast as a promising tool for symbiotic control of mosquito-borne diseases. In the present study, we have carried out a large Next Generation Sequencing (NGS) metagenomics analysis including strains associated with vector mosquitoes , and , which has highlighted wide and heterogeneous EB communities in yeast. Furthermore, we have disclosed a Matryoshka-like association in the gut of that comprises different EB in the strain of F17.12. Our investigations started with the localization of fast-moving bacteria-like bodies within the yeast vacuole of F17.12. Additional microscopy analyses have validated the presence of alive intravacuolar bacteria and 16S rDNA libraries from F17.12 have identified a few bacterial targets. Some of these EB have been isolated and tested for lytic properties and capability to re-infect the yeast cell. Moreover, a selective competence to enter yeast cell has been shown comparing different bacteria. We suggested possible tripartite interactions among EB, and the host, opening new knowledge on the vector biology.
PubMed: 37396392
DOI: 10.3389/fmicb.2023.1157299 -
BMC Microbiology Aug 2023The ascomycetous heterothallic yeast Wickerhamomyces anomalus (WA) has received considerable attention and has been widely reported in the winemaking industry for its...
BACKGROUND
The ascomycetous heterothallic yeast Wickerhamomyces anomalus (WA) has received considerable attention and has been widely reported in the winemaking industry for its distinctive physiological traits and metabolic attributes. An increased concentration of ethanol during ethanol fermentation, however, causes ethanol stress (ES) on the yeast cells. Trehalose has been implicated in improving survival under various stress conditions in microorganisms. Herein, we determined the effects of trehalose supplementation on the survival, differentially expressed genes (DEGs), cellular morphology, and oxidative stress tolerance of WA in response to ES.
RESULTS
The results indicated that trehalose improved the survival and anomalous surface and ultrastructural morphology of WA. Additionally, trehalose improved redox homeostasis by reducing the levels of reactive oxygen species (ROS) and inducing the activities of antioxidant enzymes. In addition, DEGs affected by the application of trehalose were enriched in these categories including in gene expression, protein synthesis, energy metabolism, and cell cycle pathways. Additionally, trehalose increased the content of intracellular malondialdehyde (MDA) and adenosine triphosphate.
CONCLUSIONS
These results reveal the protective role of trehalose in ES mitigation and strengthen the possible uses of WA in the wine fermentation sector.
Topics: Trehalose; Saccharomycetales; Adenosine Triphosphate; Ethanol
PubMed: 37644381
DOI: 10.1186/s12866-023-02982-y -
Foods (Basel, Switzerland) Aug 2022Physicochemical changes in fermented alcoholic beverages are significantly related to microbial community development during fermentation. Due to its unusually long...
Physicochemical changes in fermented alcoholic beverages are significantly related to microbial community development during fermentation. Due to its unusually long fermentation, , a traditional Korean house rice wine fermented with as the traditional starter, gives rise to a strong yeast community and, therefore, a high ethanol concentration and different flavors. However, no detailed analysis has been examined. Changes in microbial community structure during fermentation were examined using both culture-dependent and culture-independent methods. During fermentation, and were dominant during all stages of the fermentation. In contrast, Candida , , , and were identified as minor. appeared after the second brewing and then remained constant. Among the 19 compounds identified in this study as order-active compounds, 2-methyl-1-butanol (isoamyl alcohol) was the major compound that increased during the long fermentation stage. Most of the odor-active compounds such as 2,3-butanediol, 3-methyl-1-butanol, ethyl tetradecanoate, ethyl decanoate, ethyl dodecanoate, butanoic acid, 3-methylbutanoic acid (isovaleric acid), 2-methylbutanoic acid, 2-methyl-1-propanol, ethyl acetate, ethyl caprylate, 2-phenylethanol, and 3-methylbutyl acetate increased as the fermentation progressed during 68 days of fermentation, which showed significant differences in the concentrations of odor-active compounds of commercially fermented .
PubMed: 36076792
DOI: 10.3390/foods11172604 -
Cureus Nov 2022In view of the growing incidence of pathogenic yeast infection all over the world, this study was undertaken to understand its etiology and epidemiology in Assam.
CONTEXT
In view of the growing incidence of pathogenic yeast infection all over the world, this study was undertaken to understand its etiology and epidemiology in Assam.
AIMS
To characterize and study the antifungal susceptibility pattern of the pathogenic yeasts from the clinical samples.
SETTINGS AND DESIGN
The study was a hospital-based cross-sectional study.
METHODS AND MATERIAL
150 patients were enrolled in the study and from which clinical samples were collected. A total of 83 samples showing the growth of yeast in culture were included in the study. The yeasts were identified by conventional and BioMerieux ID 32C and VITEK 2. Antifungal susceptibility test was done by disk diffusion method as per Clinical and Laboratory Standards Institute (CLSI), M44-A2.
STATISTICAL ANALYSIS USED
Data was analyzed using statistical software Epi-Info 7.1.2.0 (2013; CDC, Atlanta, USA). For comparison of categorical data, the Chi-square test or Fisher exact test was used. A value of less than 0.05 was considered statistically significant.
RESULTS
The most affected population was the age group of ≤10 years (32.5%) with male preponderance (67.5%). Yeasts were mostly isolated bloodstream infections (49.3%). The major risk factor was prolonged antibiotic intake. Predominant yeast isolates were (43.4%) followed by (19.3%). Emerging yeasts like (4.8%), (2.4%), and (1.2%) were also isolated. Amphotericin B was effective against all yeast isolates. All the isolates of were resistant to all the azoles.
CONCLUSIONS
The study reflects that there is a growing incidence of emerging yeast infections and efforts are to be made for their identification and antifungal susceptibility testing for the initiation of appropriate therapy.
PubMed: 36532931
DOI: 10.7759/cureus.31512