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The utilization of seawater for the hydrolysis of macroalgae and subsequent bioethanol fermentation.Scientific Reports Jun 2020A novel seawater-based pretreatment process was developed to improve the hydrolysis yield of brown (Laminaria digitata), green (Ulva linza) and red (Porphyra...
A novel seawater-based pretreatment process was developed to improve the hydrolysis yield of brown (Laminaria digitata), green (Ulva linza) and red (Porphyra umbilicalis) macroalgae. Pre-treated with 5% sulphuric acid at 121 °C, 15 minutes, L. digitata, U. linza and P. umbilicalis liberated 64.63 ± 0.30%, 69.19 ± 0.11% and 63.03 ± 0.04% sugar in seawater compared with 52.82 ± 0.16%, 45.93 ± 0.37% and 48.60 ± 0.07% in reverse-osmosis water, respectively. Low hydrolysis yields (2.6-11.7%) were observed in alkali and hydrothermal pretreatment of macroalgae, although seawater led to relatively higher yields. SEM images of hydrolyzed macroalgae showed that reverse-osmosis water caused contortions in the remaining cell walls following acid and hydrothermal pre-treatments in the L. digitata and U. linza samples. Fed-batch fermentations using concentrated green seaweed hydrolysates and seawater with marine yeast Wickerhamomyces anomalus M15 produced 48.24 ± 0.01 g/L ethanol with an overall yield of 0.329 g/g available sugars. Overall, using seawater in hydrolysis of seaweed increased sugar hydrolysis yield and subsequent bioethanol production.
Topics: Biofuels; Biomass; Biotechnology; Carbohydrates; Ethanol; Fermentation; Glucose; Hydrolysis; Laminaria; Porphyra; Seawater; Seaweed; Sugars; Sulfuric Acids; Ulva
PubMed: 32546695
DOI: 10.1038/s41598-020-66610-9 -
Frontiers in Microbiology 2020The ascomycete yeast is a mutualistic symbiont of different insects, including diptera vectors of diseases. Although fungal symbioses have been so far poorly... (Review)
Review
The ascomycete yeast is a mutualistic symbiont of different insects, including diptera vectors of diseases. Although fungal symbioses have been so far poorly characterized, the topic is gaining attention as yeast-insect interactions can provide pivotal information on insect biology, such as their environmental adaptation or vectorial capability. We review the symbiosis between and mosquitoes, which implies nutritional and protective functions. Furthermore, we focus on antiplasmodial effects of in malaria vectors and discuss the yeast potential for the "symbiotic control" (SC) of mosquito-borne diseases (MBDs).
PubMed: 33552032
DOI: 10.3389/fmicb.2020.621605 -
Journal of Industrial Microbiology &... Feb 2015This study identified phenotypic traits appropriate for biotechnological applications of 118 yeasts isolated from cachaça distilleries. Different properties were...
This study identified phenotypic traits appropriate for biotechnological applications of 118 yeasts isolated from cachaça distilleries. Different properties were verified: capacity to use alternative carbon sources; ability to tolerate high concentrations of sucrose, ethanol, methanol, aluminum and zinc as well as different pH values and foam production. Pichia guilliermondii and Pichia anomala strains were identified as the most promising ones for application in the second-generation biofuel industry, showing ability to grow on high glycerol concentrations. Other isolates, identified as Saccharomyces cerevisiae, produced bioethanol comparable to the industrial strains, and were therefore ideal for use in the first-generation ethanol industry. Some of these strains also showed high resistance to aluminum, as observed in sugarcane juice, and to inter-cycle washings with diluted sulphuric acid, as performed in the industrial bioethanol production process. In summary, yeast isolates from cachaça distilleries displayed robustness and phenotypic plasticity, which makes them interesting for biotechnological applications.
Topics: Alcoholic Beverages; Aluminum; Biofuels; Bioreactors; Biotechnology; Brazil; Distillation; Ethanol; Fermentation; Glycerol; Hydrogen-Ion Concentration; Methanol; Pichia; Saccharomyces cerevisiae; Sucrose; Zinc
PubMed: 25540045
DOI: 10.1007/s10295-014-1528-y -
Applied and Environmental Microbiology Nov 2022With industrial agriculture increasingly challenging our ecological limits, alternative food production routes such as microbial protein (MP) production are receiving...
With industrial agriculture increasingly challenging our ecological limits, alternative food production routes such as microbial protein (MP) production are receiving renewed interest. Among the multiple substrates so far evaluated for MP production, renewable bioethanol (EtOH) is still underexplored. Therefore, the present study investigated the cultivation of five microorganisms (2 bacteria, 3 yeasts) under carbon (C), nitrogen (N), and dual C-N-limiting conditions (molar C/N ratios of 5, 60, and 20, respectively) to evaluate the production (specific growth rate, protein and biomass yield, production cost) as well as the nutritional characteristics (protein and carbohydrate content, amino acid [AA] profile) of MP production from bioethanol. Under C-limiting conditions, all the selected microorganisms showed a favorable AA profile for human nutrition (average AA score of 1.5 or higher), with a negative correlation between protein content and growth rate. Maximal biomass yields were achieved under conditions where no extracellular acetate was produced. Cyberlindnera saturnus and Wickerhamomyces anomalus displayed remarkably high biomass yields (0.40 to 0.82 g cell dry weight [CDW]/g EtOH), which was reflected in the lowest estimated biomass production costs when cultivated with a C/N ratio of 20. Finally, when the production cost was evaluated on a protein basis, Corynebacterium glutamicum grown under C-limiting conditions showed the most promising economic outlook. The global protein demand is rapidly increasing at rates that cannot be sustained, with projections showing 78% increased global protein needs by 2050 (361 compared to 202 million ton/year in 2017). In the absence of dedicated mitigation strategies, the environmental effects of our current food production system (relying on agriculture) are expected to surpass the planetary boundaries-the safe operating space for humanity-by 2050. Here, we illustrate the potential of bioethanol-renewable ethanol produced from side streams-as a main resource for the production of microbial protein, a radically different food production strategy in comparison to traditional agriculture, with the potential to be more sustainable. This study unravels the kinetic, productive, and nutritional potential for microbial protein production from bioethanol using the bacteria Methylorubrum extorquens and Corynebacterium glutamicum and the yeasts Cyberlindnera saturnus, and Metschnikowia pulcherrima, setting the scene for microbial protein production from renewable ethanol.
Topics: Humans; Nitrogen; Carbon; Biomass; Ethanol; Yeasts; Fermentation; Biofuels
PubMed: 36286523
DOI: 10.1128/aem.01188-22 -
Journal of the Science of Food and... Jul 2020As one of the origin centers of domesticated plants in the world, Ethiopia is rich in diversified fermented foods and beverages, in which yeasts are usually among the...
BACKGROUND
As one of the origin centers of domesticated plants in the world, Ethiopia is rich in diversified fermented foods and beverages, in which yeasts are usually among the essential functional microorganisms. This study aims to investigate yeast species diversity and distribution in indigenous fermented products in Ethiopia using conventional isolation and molecular identification methods.
RESULT
Yeast cell counts in 221 samples of various Ethiopian traditional fermented products, including fermented staple foods, alcoholic beverages, dairy products, and condiments, were compared using the typical dilution plating method. A total of 475 yeast isolates were recovered from these samples and 41 yeast species belonging to 25 genera were identified from yeast isolates using the sequence analysis of the D1/D2 domain of the large subunit of rRNA gene. Candida humilis, Wickerhamomyces anomalus, Meyerozyma guilliermondii, Pichia kudriavzevii, and Saccharomyces cerevisiae were the most dominant species that were widely distributed among the majority of the fermented products analyzed in the current study.
CONCLUSION
Significant variations were encountered both in yeast cell counts, diversity, and distribution of yeast species among different types of fermented products and even among different samples of the same types of fermented products. It calls for a more extensive and systematic microbiological study of Ethiopian indigenous fermented foods, beverages and other related products that can be helpful for standardization and large-scale production of these foods in Ethiopia. © 2020 Society of Chemical Industry.
Topics: Beverages; Biodiversity; Ethiopia; Fermentation; Fermented Foods; Food Microbiology; Phylogeny; Yeasts
PubMed: 32201947
DOI: 10.1002/jsfa.10391 -
Cureus Feb 2024We report the case of an 84-year-old man with a history of IgG4-related sclerosing cholangitis who was diagnosed with advanced esophageal cancer and underwent radiation...
We report the case of an 84-year-old man with a history of IgG4-related sclerosing cholangitis who was diagnosed with advanced esophageal cancer and underwent radiation and chemotherapy. An implantable central venous access port was placed for chemotherapy and total parenteral nutrition. The patient presented with a fever and received antimicrobial therapy for acute cholangitis but remained febrile, and subsequently, yeast was detected in the aerobic bottle of blood culture obtained from the central venous line. The yeast was identified as . Liposomal amphotericin B was administered, and the central line access port was removed. After confirmation of negative blood cultures and 14 days post treatment, he underwent reinsertion of the central line access port. Due to persistent pain at the insertion site, fluconazole was added for an additional 14 days, and the patient was discharged and transferred to another hospital. is a rare fungal infection with other synonyms including , , and . A literature review of 53 case reports of , , , and was conducted, with a total of 211 cases reviewed. Fungemia was reported in 94% of cases, with central venous catheterization, parental feeding, low birth weight, and immunocompromised status identified as major risk factors. The majority of cases were pediatric, particularly neonatal, and there were reports of nosocomial infections causing outbreaks, with some cases involving the eye such as endophthalmitis or keratitis.
PubMed: 38445156
DOI: 10.7759/cureus.53550 -
Food Microbiology Feb 2022In the present study, for the first time, high sensitive quantitative polymerase chain reaction (qPCR) and digital droplet polymerase chain reaction (ddPCR) assays were...
Development of quantitative real-time PCR and digital droplet-PCR assays for rapid and early detection of the spoilage yeasts Saccharomycopsis fibuligera and Wickerhamomyces anomalus in bread.
In the present study, for the first time, high sensitive quantitative polymerase chain reaction (qPCR) and digital droplet polymerase chain reaction (ddPCR) assays were developed to detect and quantify total eumycetes with potential application in several food matrices and to specifically determine the level of contamination by Saccharomycopsis fibuligera and Wickerhamomyces anomalus cells directly in bread. Among the candidate target genes used to develop the assays, car1 gene was chosen to detect the two spoilage yeasts S. fibuligera and W. anomalus. The specificity of the PCR assays was tested using purified genomic DNA from 36 bacterial and fungal strains. The sensitivity of the assays was defined by using tenfold serial dilutions of genomic DNA starting from 10 cfu/mL to 1 cfu/mL of S. fibuligera and W. anomalus. Validation of the assays was achieved by enumeration of S. fibuligera and W. anomalus DNA copies from samples of artificially contaminated bread homogenates detecting up to 10 cfu/mL (0.06 ± 0.01 copies/μL) of W. anomalus by using ddPCR. In conclusion, the developed qPCR and ddPCR assays demonstrate strong performance in the early detection of S. fibuligera and W. anomalus in bread, representing promising tools for applying high-throughput approaches to regularly monitor bread quality.
Topics: Bread; Food Contamination; Real-Time Polymerase Chain Reaction; Saccharomycetales; Saccharomycopsis; Sensitivity and Specificity; Yeasts
PubMed: 34579854
DOI: 10.1016/j.fm.2021.103894 -
Foods (Basel, Switzerland) Oct 2023Currently, non- yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation...
Currently, non- yeasts are the subject of interest, among other things, for their contribution to the aromatic complexity of wines. In this study, the characterisation of non- yeasts was addressed by their isolation during spontaneous fermentations of organic Verdejo grapes, obtaining a total of 484 isolates, of which 11% were identified by molecular techniques as non- yeasts. Fermentative isolates belonging to the species , , , , , and were analysed. Significant differences were found in the yeast populations established at the different fermentation stages. Interestingly, stood up as a widely distributed species in vineyards, vintages, and fermentation stages. Several of the strains studied stood out for their biotechnological potential in the production of Verdejo wine, showing the presence of relevant enzymatic activity for the release of varietal aromas and the technological improvement of the winemaking process. Three enzymatic activities were found in an important number of isolates, β-glucosidase, protease, and β-lyase, implicated in the positive aromatic impact on this style of white wine. In that sense, all the isolates of presented those activities. isolates were highlighted for their significant β-lyase activity. In addition, was outlined because of its potential to achieve an elevated fermenting power, as well as the lack of lag phase. The results obtained highlight the importance of maintaining the microbial diversity that contributes to the production of wines with unique and distinctive characteristics of the production region.
PubMed: 37835297
DOI: 10.3390/foods12193644 -
Microbial Cell Factories Sep 2015The product yield and titers of biological processes involving the conversion of biomass to desirable chemicals can be limited by environmental stresses encountered by...
BACKGROUND
The product yield and titers of biological processes involving the conversion of biomass to desirable chemicals can be limited by environmental stresses encountered by the microbial hosts used for the bioconversion. One of these main stresses is growth inhibition due to exposure to low pH conditions. In order to circumvent this problem, understanding the biological mechanisms involved in acid stress response and tolerance is essential. Characterisation of wild yeasts that have a natural ability to resist such harsh conditions will pave the way to understand the biological basis underlying acid stress resistance. Pichia anomala possesses a unique ability to adapt to and tolerate a number of environmental stresses particularly low pH stress giving it the advantage to outcompete other microorganisms under such conditions. However, the genetic basis of this resistance has not been previously studied.
RESULTS
To this end, we isolated an acid resistant strain of P. anomala, performed a gross phenotypic characterisation at low pH and also performed a whole genome and total RNA sequencing. By integrating the RNA-seq data with the genome sequencing data, we found that several genes associated with different biological processes including proton efflux, the electron transfer chain and oxidative phosphorylation were highly expressed in P. anomala cells grown in low pH media. We therefore present data supporting the notion that a high expression of proton pumps in the plasma membrane coupled with an increase in mitochondrial ATP production enables the high level of acid stress tolerance of P. anomala.
CONCLUSIONS
Our findings provide insight into the molecular and genetic basis of low pH tolerance in P. anomala which was previously unknown. Ultimately, this is a step towards developing non-conventional yeasts such as P. anomala for the production of industrially relevant chemicals under low pH conditions.
Topics: Adenosine Triphosphate; Amino Acid Sequence; Biomass; Electron Transport; Fungal Proteins; Genome, Fungal; Hydrogen-Ion Concentration; Mitochondria; Models, Molecular; Molecular Sequence Data; Oxidative Phosphorylation; Pichia; Sequence Alignment; Sequence Analysis, RNA; Stress, Physiological; Transcriptome
PubMed: 26376644
DOI: 10.1186/s12934-015-0331-4 -
Journal of Industrial Microbiology &... Oct 2015The phytase of the yeast Pichia anomala (PPHY) is a suitable biocatalyst as a food and feed additive because of its adequate thermostability, acid stability, protease...
The phytase of the yeast Pichia anomala (PPHY) is a suitable biocatalyst as a food and feed additive because of its adequate thermostability, acid stability, protease insensitivity and broad substrate spectrum. The cell-bound nature and low phytase titres are the main bottlenecks for its utility in food and feed industries. In this investigation, we have overcome the problems by constitutive secretory expression of PPHY under glyceraldehyde phosphate dehydrogenase (GAP) promoter. A ~44-fold increase in rPPHY titre has been achieved after optimization of cultural variables by one-variable-at-a-time approach and two factorial statistical design. The use of GAP promoter makes the cultivation of the recombinant P. pastoris straight forward and eliminates the requirement of methanol for induction and hazards associated with its storage. Among metal-phytate complexes, Ca(2+) phytate is hydrolyzed more efficiently by rPPHY than Co(2+), Mn(2+), Mg(2+), Fe(3+) and Zn(2+) phytates. The enzyme is effective in dephytinizing whole wheat unleavened flat Indian breads (naan and tandoori) and different broiler feeds, thus mitigating anti-nutritional effects of phytates.
Topics: 6-Phytase; Animal Feed; Animals; Bread; Chickens; Enzyme Stability; Food Additives; Glyceraldehyde-3-Phosphate Dehydrogenases; Hydrolysis; Phytic Acid; Pichia; Promoter Regions, Genetic; Recombinant Proteins; Substrate Specificity; Triticum
PubMed: 26264930
DOI: 10.1007/s10295-015-1670-1