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Journal of the Science of Food and... Mar 2023Microencapsulated yeasts are a novel alternative as a delivery matrix for microbiological starters. This technology aims to protect the active compounds from adverse...
BACKGROUND
Microencapsulated yeasts are a novel alternative as a delivery matrix for microbiological starters. This technology aims to protect the active compounds from adverse environmental conditions and prolong their useful life and could also improve the conditions of the starters for cocoa fermentation. The present study established the effective dose to apply the microencapsulated yeast Pichia kudriavzevii as a microbiological starter of fermentation and biotechnological strategy for promoting the biochemical dynamics and sensory expression of the cocoa variety CCN-51. For this, 0.5%, 1%, 2%, and 3% of microencapsulated P. kudriavzevii yeast insolated from the artisanal fermentation process of cocoa was added to the cocoa mass to be fermented and studied on a laboratory scale.
RESULTS
The partial least squares regression of fermentation was related in four quartiles, comprising the hedonic judgments of the sensory evaluation with the biochemical traits of the cocoa liquor, finding a high correlation between the physicochemical variables total phenols, percentage of insufficiently fermented grains, and percentage of total acidity, with a level of bitterness and defects found in liquors with the addition of 0.5% of microencapsulated starter. The treatments with the addition of 2% and 3% of the inoculum showed a high correlation between the variables pH, total anthocyanins, cocoa, fruity and floral aromas, sweet taste, and general aroma perception.
CONCLUSION
The higher presence of volatile compounds such as 2,3-butanediol associated with cocoa aroma and 1-phenyl-2-ethanol and acetophenone associated with aromatic descriptors of fruity and floral series allowed establishment in 2% of microencapsulated P. kudriavzevii yeast, comprising the effective dose for promoting the biochemical dynamics of laboratory-scale fermentation and the development of cocoa, as well as the fruity and floral aromas of cocoa CCN-51 liquor. The microencapsulation is suitable for cocoa starters. © 2023 Society of Chemical Industry.
Topics: Cacao; Fermentation; Saccharomyces cerevisiae; Anthocyanins; Genotype
PubMed: 36606570
DOI: 10.1002/jsfa.12433 -
Scientific Reports Nov 2023This study addresses the environmental risks associated with the accumulation of keratin waste from poultry, which is resistant to conventional protein degradation...
This study addresses the environmental risks associated with the accumulation of keratin waste from poultry, which is resistant to conventional protein degradation methods. To tackle this issue, microbial keratinases have emerged as promising tools for transforming resilient keratin materials into valuable products. We focus on the Metalloprotease (MetPr) gene isolated from novel Pichia kudriavzevii YK46, sequenced, and deposited in the NCBI GenBank database with the accession number OQ511281. The MetPr gene encodes a protein consisting of 557 amino acids and demonstrates a keratinase activity of 164.04 U/ml. The 3D structure of the protein was validated using Ramachandran's plot, revealing that 93% and 97.26% of the 557 residues were situated within the most favoured region for the MetPr proteins of template Pichia kudriavzevii strain 129 and Pichia kudriavzevii YK46, respectively. Computational analyses were employed to determine the binding affinities between the deduced protein and beta keratin. Molecular docking studies elucidated the optimal binding affinities between the metalloprotease (MetPr) and beta-keratin, yielding values of - 260.75 kcal/mol and - 257.02 kcal/mol for the template strains Pichia kudriavzevii strain 129 and Pichia kudriavzevii YK46, respectively. Subsequent molecular cloning and expression of the MetPr gene in E. coli DH5α led to a significantly higher keratinase activity of 281 ± 12.34 U/ml. These findings provide valuable insights into the potential of the MetPr gene and its encoded protein for keratin waste biotransformation, with implications for addressing environmental concerns related to keratinous waste accumulation.
Topics: Animals; Feathers; Escherichia coli; Molecular Docking Simulation; Pichia; Metalloproteases; Keratins; Cloning, Molecular
PubMed: 37968282
DOI: 10.1038/s41598-023-47179-5 -
Biological Trace Element Research Feb 2021The cadmium and lead binding capacities and antioxidant activities of Lactobacillus plantarum and Pichia kudriavzevii were evaluated in vitro and in vivo. Lactic acid...
The cadmium and lead binding capacities and antioxidant activities of Lactobacillus plantarum and Pichia kudriavzevii were evaluated in vitro and in vivo. Lactic acid bacteria and yeasts obtained from fermenting cassava mash and maize slurry were screened for tolerance to cadmium and lead at 500-1050 mg ml screened for probiotic potentials and antioxidant activities such as 2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant properties. The in vivo studies were carried out in male Wistar rats. The strains identified as Lactobacillus plantarum ML05 and Pichia kudriavzevii FY05 demonstrated the best probiotic potentials and antioxidant activities. Alterations in antioxidant capacities were positive in the treatment groups. The histopathology displayed positive changes in the renal tubules and glomeruli, hypertrophy, with normal capsular spaces without inflammation in the kidney, while the liver sinusoids appear normal in the rats administered with L. plantarum ML05 and P. kudriavzevii FY05 while the infected and not treated showed cell necrosis induced by toxicities. Our results provided new evidence that Lactobacillus plantarum and Pichia kudriavzevii have different biological actions on the heavy metals binding capacities and antioxidant activities in experimental animals. This study suggests that these microorganisms can be considered dietary therapeutics against cadmium and lead toxicities.
Topics: Animals; Antioxidants; Cadmium; Lactobacillus plantarum; Lead; Male; Pichia; Probiotics; Rats; Rats, Wistar
PubMed: 32436065
DOI: 10.1007/s12011-020-02164-1 -
Metabolic Engineering Jan 2023Currently, the biological production of L-malic acid (L-MA) is mainly based on the fermentation of filamentous fungi at near-neutral pH, but this process requires large...
Currently, the biological production of L-malic acid (L-MA) is mainly based on the fermentation of filamentous fungi at near-neutral pH, but this process requires large amounts of neutralizing agents, resulting in the generation of waste salts when free acid is obtained in the downstream process, and the environmental hazards associated with the waste salts limit the practical application of this process. To produce L-MA in a more environmentally friendly way, we metabolically engineered the acid-tolerant yeast Pichia kudriavzevii and achieved efficient production of L-MA through low pH fermentation. First, an initial L-MA-producing strain that relies on the reductive tricarboxylic acid (rTCA) pathway was constructed. Subsequently, the L-MA titer and yield were further increased by fine-tuning the flux between the pyruvate and oxaloacetate nodes. In addition, we found that the insufficient supply of NADH for cytoplasmic malate dehydrogenase (MDH) hindered the L-MA production at low pH, which was resolved by overexpressing the soluble pyridine nucleotide transhydrogenase SthA from E. coli. Transcriptomic and metabolomic data showed that overexpression of EcSthA contributed to the activation of the pentose phosphate pathway and provided additional reducing power for MDH by converting NADPH to NADH. Furthermore, overexpression of EcSthA was found to help reduce the accumulation of the by-product pyruvate but had no effect on the accumulation of succinate. In microaerobic batch fermentation in a 5-L fermenter, the best strain, MA009-10-URA3 produced 199.4 g/L L-MA with a yield of 0.94 g/g glucose (1.27 mol/mol), with a productivity of 1.86 g/L/h. The final pH of the fermentation broth was approximately 3.10, meaning that the amount of neutralizer used was reduced by more than 50% compared to the common fermentation processes using filamentous fungi. To our knowledge, this is the first report of the efficient bioproduction of L-MA at low pH and represents the highest yield of L-MA in yeasts reported to date.
Topics: Saccharomyces cerevisiae; Escherichia coli; Metabolic Engineering; NAD; Salts; Fermentation; Pyruvates; Hydrogen-Ion Concentration
PubMed: 36566973
DOI: 10.1016/j.ymben.2022.12.007 -
Food Chemistry: X Oct 2023Microbial activity during spontaneous fermentation in alcoholic beverages have driven in developing the chemical and aromatic characteristic of products but not clear in...
Microbial activity during spontaneous fermentation in alcoholic beverages have driven in developing the chemical and aromatic characteristic of products but not clear in apricot wines. We have characterised the composition of fungal communities and volatile metabolites in apricot wine spontaneous fermentation among two Shaanxi regions. Results showed that , , and , were the dominant fungi in apricot wine fermentation. A total of 80 volatiles including esters, alcohols, acids and terpenes were detected from two apricot wines. Their correlations suggested that apricot wine aroma was mainly affected by , rather than we commonly considered. Furthermore, reinforced inoculation of LQD20 has exhibited the commendable potential in enhancing sensory qualities. The results of this study provide fundamental information of the indigenous microbiota in microbial dynamic during apricot wine fermentation, which would be helpful in exploiting the strains with potential for industrial use as starter cultures.
PubMed: 37780311
DOI: 10.1016/j.fochx.2023.100862 -
Journal of Biomolecular Structure &... 2022One of the major constraints limiting the use of abundantly available lignocellulosic biomass as potential feedstock for alcohol industry is the lack of C/C co-sugar...
One of the major constraints limiting the use of abundantly available lignocellulosic biomass as potential feedstock for alcohol industry is the lack of C/C co-sugar fermenting yeast. The present study explores a mutant yeast BGY1-γm as a potential strain for bioconversion of glucose/xylose sugars of green biomass into ethanol under batch fermentation. The mutant strain having higher alcohol dehydrogenase activity (11.31%) showed significantly higher ethanol concentration during co-fermentation of glucose/xylose sugars (14.2%) as compared to the native strain. Based on 99% sequence similarity of ADH encoding gene from the mutant with the gene sequences from other yeast strains, the ADH enzyme was identified as ADH-1 type. The study reveals first three-dimensional model of ADH-1 utilizing glucose/xylose sugars from BGY1-γm (ADH mutant). The refined and validated model of ADH mutant was used for molecular docking against the substrate (acetaldehyde) and product (ethanol). Molecular docking results showed that substrate and product exhibited a binding affinity of -4.55 and -4.5 kcal/mol with ADH mutant. Acetaldehyde and ethanol interacted at the active site of ADH mutant via hydrogen bonds (Ser42, His69 and Asp163) and hydrophobic interactions (Cys40, Ser42, His69, Cys95, Trp123 and Asp163) to form the stable protein-ligand complex. Molecular dynamics analysis revealed that ADH-mutant acetaldehyde and ADH-mutant ethanol complexes were more stable than ADH mutant. MMPBSA binding energy confirmed that binding of substrate and product results in the formation of a lower energy stable protein-ligand complex.Communicated by Ramaswamy H. Sarma.
Topics: Saccharomyces cerevisiae; Ethanol; Alcohol Dehydrogenase; Xylose; Molecular Docking Simulation; Ligands; Acetaldehyde; Glucose; Fermentation
PubMed: 34424128
DOI: 10.1080/07391102.2021.1967196 -
Metabolic Engineering Communications Jun 2020Itaconic acid (IA), or 2-methylenesuccinic acid, has a broad spectrum of applications in the biopolymer industry owing to the presence of one vinyl bond and two acid...
Itaconic acid (IA), or 2-methylenesuccinic acid, has a broad spectrum of applications in the biopolymer industry owing to the presence of one vinyl bond and two acid groups in the structure. Its polymerization can follow a similar mechanism as acrylic acid but additional functionality can be incorporated into the extra beta acid group. Currently, the bio-based production of IA in industry relies on the fermentation of the filamentous fungus . However, the difficulties associated with the fermentation undertaken by filamentous fungi together with the pathogenic potential of pose a serious challenge for industrial-scale production. In recent years, there has been increasing interest in developing alternative production hosts for fermentation processes that are more homogenous in the production of organic acids. is a non-conventional yeast with high acid tolerance to organic acids at low pH, which is a highly desirable trait by easing downstream processing. We introduced -aconitic acid decarboxylase gene () from (designated ) into this yeast and established the initial titer of IA at 135 ± 5 mg/L. Subsequent overexpression of a native mitochondrial tricarboxylate transporter (herein designated ) presumably delivered -aconitate efficiently to the cytosol and doubled the IA production. By introducing the newly invented CRISPR-Cas9 system into . , we successfully knocked out both copies of the gene encoding isocitrate dehydrogenase (), aiming to increase the availability of -aconitate. The resulting strain, devoid of and overexpressing and on its genome produced IA at 505 ± 17.7 mg/L in shake flasks, and 1232 ± 64 mg/L in fed-batch fermentation. Because the usage of an acid-tolerant species does not require pH adjustment during fermentation, this work demonstrates the great potential of engineering . as an industrial chassis for the production of organic acid.
PubMed: 32346511
DOI: 10.1016/j.mec.2020.e00124 -
PLoS Pathogens May 2023The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida...
The pathogenic yeast Pichia kudriavzevii, previously known as Candida krusei, is more distantly related to Candida albicans than clinically relevant CTG-clade Candida species. Its cell wall, a dynamic organelle that is the first point of interaction between pathogen and host, is relatively understudied, and its wall proteome remains unidentified to date. Here, we present an integrated study of the cell wall in P. kudriavzevii. Our comparative genomic studies and experimental data indicate that the general structure of the cell wall in P. kudriavzevii is similar to Saccharomyces cerevisiae and C. albicans and is comprised of β-1,3-glucan, β-1,6-glucan, chitin, and mannoproteins. However, some pronounced differences with C. albicans walls were observed, for instance, higher mannan and protein levels and altered protein mannosylation patterns. Further, despite absence of proteins with high sequence similarity to Candida adhesins, protein structure modeling identified eleven proteins related to flocculins/adhesins in S. cerevisiae or C. albicans. To obtain a proteomic comparison of biofilm and planktonic cells, P. kudriavzevii cells were grown to exponential phase and in static 24-h cultures. Interestingly, the 24-h static cultures of P. kudriavzevii yielded formation of floating biofilm (flor) rather than adherence to polystyrene at the bottom. The proteomic analysis of both conditions identified a total of 33 cell wall proteins. In line with a possible role in flor formation, increased abundance of flocculins, in particular Flo110, was observed in the floating biofilm compared to exponential cells. This study is the first to provide a detailed description of the cell wall in P. kudriavzevii including its cell wall proteome, and paves the way for further investigations on the importance of flor formation and flocculins in the pathogenesis of P. kudriavzevii.
Topics: Saccharomyces cerevisiae; Proteome; Proteomics; Candida albicans; Candida; Biofilms; Genomics; Cell Wall
PubMed: 37196016
DOI: 10.1371/journal.ppat.1011158 -
New Biotechnology Jul 2022Oleaginous yeasts offer an interesting possibility for renewable lipid production, since the single cell oil accumulated can be based on a wide range of cheap,...
Oleaginous yeasts offer an interesting possibility for renewable lipid production, since the single cell oil accumulated can be based on a wide range of cheap, waste-derived carbon sources. Here, several short chain carboxylic acids and sugars commonly found in these substrates were assessed as carbon sources for Apiotrichum brassicae and Pichia kudriavzevii. While both strains were able to utilize all carbon sources employed, high volumetric lipid productivities (0.4 g/Lh) and lipid contents (68%) could be reached particularly with acetic acid as carbon source. Odd-numbered volatile fatty acids led to lower productivities and lipid contents, but the lipids contained unusually high proportions of odd-numbered fatty acids (up to 80% of total fatty acids). These fatty acids are rather uncommon in nature and might offer the possibility for various high value applications. In conclusion both strains are able to utilize a wide range of substrates potentially present in waste-derived substrates. Lipid content and volumetric lipid productivity strongly depend on the carbon source, with even-numbered volatile fatty acids resulting in the highest values. For volatile fatty acids in particular, the carbon source also strongly influences the composition of the lipids produced by the yeast strains.
Topics: Basidiomycota; Biofuels; Carbon; Fatty Acids; Fatty Acids, Volatile; Pichia; Yeasts
PubMed: 35182781
DOI: 10.1016/j.nbt.2022.02.003 -
Journal of Basic Microbiology Sep 2019Removal of heavy metals from food material by growing micro-organisms is limited by the toxicity to cells. In this study, different preincubation treatments were...
Removal of heavy metals from food material by growing micro-organisms is limited by the toxicity to cells. In this study, different preincubation treatments were investigated to analyze their effects on cadmium resistance and removal ability of Pichia kudriavzevii A16 and Saccharomyces cerevisiae CICC1211. Sucrose preincubation improved the cadmium resistance of both yeast cells and increased the cadmium-removal rate of P. kudriavzevii A16. An evident decrease of intracellular and cell-surface cadmium accumulation was observed after sucrose preincubation, which may be the primary reason responsible for the improved cadmium resistance. Flow cytometry assay showed that sucrose significantly reduced the production of reactive oxygen species (ROS) and cell death rate of both yeasts under cadmium compared with those normally cultured cells. Under cadmium stress, the content of both protein carbonyls and malonyldialdehyde were also reduced by the addition of sucrose, the results were in accordance with the tendency of ROS, exhibiting a defending function of sucrose. Osmotic regulators as proline and trehalose were increased by sucrose preincubation in P. kudriavzevii A16 in the presence of cadmium. The results suggested that sucrose preincubation could be applied to improve cadmium resistance and removal rate of yeasts.
Topics: Biodegradation, Environmental; Cadmium; Microbial Viability; Pichia; Proline; Reactive Oxygen Species; Saccharomyces cerevisiae; Stress, Physiological; Sucrose; Trehalose
PubMed: 31347180
DOI: 10.1002/jobm.201900272