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Journal of Food Science and Technology Jul 2022Volatile organic compounds (VOCs) are important to determine the aroma and sensory perception of cocoa. Starter cultures can modulate the volatile profile of cocoa beans...
Volatile organic compounds (VOCs) are important to determine the aroma and sensory perception of cocoa. Starter cultures can modulate the volatile profile of cocoa beans during fermentation. This study aimed to determine the VOCs and sensory of chocolates produced using cocoa beans fermented with yeast starters ( (MH979681) (MH979675) and the mixture of the two yeasts (Mix)). The VOCs of chocolates were determined by Head-Space Solid Phase Microextraction followed by Gas Chromatography-Mass Spectrophotometry. Sensory analysis was determined by using trained panels. VOCs profiles of chocolates produced using beans fermented with HT, PK or Mix were noticeably different from Ghana and control chocolates (no starter). The addition of yeast starters during cocoa fermentation produced chocolates that were preferred by trained panels. Bitterness and astringency were the more intense flavour attributes in chocolates produced using cocoa beans added with yeast starters. The chocolate produced using cocoa beans fermented with PK was the most acidic; whereas chocolate produced using beans fermented with Mix had the sweetest taste. The addition of PK or HT is helpful in producing chocolate with a distinct flavour.
PubMed: 35734109
DOI: 10.1007/s13197-021-05292-1 -
Bioprocess and Biosystems Engineering Jul 2017The importance of non-Saccharomyces yeast species in fermentation processes is widely acknowledged. Within this group, Pichia kudriavzevii ITV-S42 yeast strain shows...
The importance of non-Saccharomyces yeast species in fermentation processes is widely acknowledged. Within this group, Pichia kudriavzevii ITV-S42 yeast strain shows particularly desirable characteristics for ethanol production. Despite this fact, a thorough study of the metabolic and kinetic characteristics of this strain is currently unavailable. The aim of this work is to study the nutritional requirements of Pichia kudriavzevii ITV-S42 strain and the effect of different carbon sources on the growth and ethanol production. Results showed that glucose and fructose were both assimilated and fermented, achieving biomass and ethanol yields of 0.37 and 0.32 gg, respectively. Glycerol was assimilated but not fermented; achieving a biomass yield of 0.88 gg. Xylose and sucrose were not metabolized by the yeast strain. Finally, the use of a culture medium enriched with salts and yeast extract favored glucose consumption both for growth and ethanol production, improving ethanol tolerance reported for this genre (35 g L) to 90 g L maximum ethanol concentration (over 100%). Furthermore Pichia kudriavzevii ITV-S42 maintained its fermentative capacity up to 200 g L initial glucose, demonstrating that this yeast is osmotolerant.
Topics: Carbon; Ethanol; Fermentation; Pichia; Sorghum; Xylose
PubMed: 28447168
DOI: 10.1007/s00449-017-1769-z -
Current Opinion in Biotechnology Dec 2016Succinic acid (SA) has been recognized as one of the most important bio-based building block chemicals due to its numerous potential applications. For the economical... (Review)
Review
Succinic acid (SA) has been recognized as one of the most important bio-based building block chemicals due to its numerous potential applications. For the economical bio-based production of SA, extensive research works have been performed on developing microbial strains by metabolic engineering as well as fermentation and downstream processes. Here we review metabolic engineering strategies applied for bio-based production of SA using representative microorganisms, including Saccharomyces cerevisiae, Pichia kudriavzevii, Escherichia coli, Mannheimia succiniciproducens, Basfia succiniciproducens, Actinobacillus succinogenes, and Corynebacterium glutamicum. In particular, strategies employed for developing engineered strains of these microorganisms leading to the best performance indices (titer, yield, and productivity) are showcased based on the published papers as well as patents. Those processes currently under commercialization are also analyzed and future perspectives are provided.
Topics: Bacteria; Fermentation; Fungi; Metabolic Engineering; Phylogeny; Succinic Acid
PubMed: 26990278
DOI: 10.1016/j.copbio.2016.02.034 -
Food Science and Biotechnology 2017Thermotolerant yeast strains were isolated from , a traditional Korean fermentation starter in which variety of microorganisms are present. Among the isolates, the...
Thermotolerant yeast strains were isolated from , a traditional Korean fermentation starter in which variety of microorganisms are present. Among the isolates, the MBY1358 identified as yeast showed significantly higher growth rate (0.59 ± 0.00 1/h) at 44 °C than other strains. Maximum ethanol concentration of 8.35 ± 0.03 g/L was obtained from 20 g/L glucose with yield of 0.44 ± 0.01 g/g at 44 °C, which is 1.14 times ethanol production of the control strain of . The MBY1358, which was significantly more thermotolerant than the control strain and fermented 200 g/L glucose to 107.33 ± 5.03 g/L ethanol at 44 °C, was deposited to Korean Collection for Type Cultures (KCTC) under the accession number 27654.
PubMed: 30263670
DOI: 10.1007/s10068-017-0155-6 -
World Journal of Microbiology &... Jan 2021The role of the yeast community in Chinese strong-flavor baijiu fermentation was investigated by culture-independent and culture-dependent methods based on 26S rDNA...
The role of the yeast community in Chinese strong-flavor baijiu fermentation was investigated by culture-independent and culture-dependent methods based on 26S rDNA sequence analysis. 92 yeast species belonging to 54 genera were found by Illumina sequencing during the fermentation of strong-flavor baijiu "Wuliangye" and 306 strains belonging to 28 species, which covered all species with more than 1% of relative abundance, were isolated and identified. Kazachstania exigua, Geotrichum silvicola, Pichia kudriavzevii, Saccharomyces cerevisiae, Zyosaccharomyces bailii, and K. humilis were found to be the first six dominant species, and their proportion varied with different fermentation stages. K. exigua was the most important yeast species responsible for the production of ethanol with the assistance of P. kudriavzevii and Z. bailii in the vigorous stage and P. kudriavzevii and G. silvicola in the continuous fermentation stage. Higher alcohols were mainly produced by K. exigua, P. kudriavzevii, S. cerevisiae, and Z. bailii in the vigorous fermentation stage, which was stimulated by more oxygen in the grains of the upper strata. K. exigua, P. kudrizevii, S. cerevisiae, Z. bailii, G. silvicola, and Trichosporon ovoides promoted the formation of ethyl alcohol. The results revealed the key roles of K. exigua, G. silvicola, and P. kudriavzevii in the fermentation of strong-flavor baijiu. The functions of these species should be confirmed by a further study based on the fermentation characteristics of isolated yeast strains gathered in this study. Distribution and function of dominant yeast species in the fermentation of strong flavor baijiu.
Topics: Basidiomycota; Candida; Ethanol; Fermentation; Flavoring Agents; Geotrichum; Phylogeny; Pichia; Saccharomyces cerevisiae; Saccharomycetales; Taste
PubMed: 33427975
DOI: 10.1007/s11274-020-02988-y -
Scientific Reports Nov 2023Second-generation bioethanol production using lignocellulosic biomass as feedstock requires a highly efficient multistress-tolerant yeast. This study aimed to develop a...
Adaptive laboratory evolution under acetic acid stress enhances the multistress tolerance and ethanol production efficiency of Pichia kudriavzevii from lignocellulosic biomass.
Second-generation bioethanol production using lignocellulosic biomass as feedstock requires a highly efficient multistress-tolerant yeast. This study aimed to develop a robust yeast strain of P. kudriavzevii via the adaptive laboratory evolution (ALE) technique. The parental strain of P. kudriavzevii was subjected to repetitive long-term cultivation in medium supplemented with a gradually increasing concentration of acetic acid, the major weak acid liberated during the lignocellulosic pretreatment process. Three evolved P. kudriavzevii strains, namely, PkAC-7, PkAC-8, and PkAC-9, obtained in this study exhibited significantly higher resistance toward multiple stressors, including heat, ethanol, osmotic stress, acetic acid, formic acid, furfural, 5-(hydroxymethyl) furfural (5-HMF), and vanillin. The fermentation efficiency of the evolved strains was also improved, yielding a higher ethanol concentration, productivity, and yield than the parental strain, using undetoxified sugarcane bagasse hydrolysate as feedstock. These findings provide evidence that ALE is a practical approach for increasing the multistress tolerance of P. kudriavzevii for stable and efficient second-generation bioethanol production from lignocellulosic biomass.
Topics: Acetic Acid; Cellulose; Ethanol; Saccharomyces cerevisiae; Biomass; Furaldehyde; Saccharum; Fermentation
PubMed: 38017261
DOI: 10.1038/s41598-023-48408-7 -
Translational Animal Science Jul 2020Growth performance, liver and spleen weight, plasma, and ceca digesta metabolites and incidences of diarrhea were investigated in growing pigs fed spent biomass of...
Growth performance, liver and spleen weight, plasma, and ceca digesta metabolites and incidences of diarrhea were investigated in growing pigs fed spent biomass of Ninety six barrows (~25 kg, 4 pigs/pen) were fed 1 of 4 experimental diets ( = 6) for 7 weeks. The diets were control, corn-, and soybean meal-based diet or control plus 2.5%, 3.75%, or 5.0% . Diets were formulated to be isocaloric and iso nitrogenous. Feed intake and body weight (BW) were recorded weekly for calculation of average daily gain (ADG), average daily feed intake (ADFI), and gain to feed ratio (G:F). Fecal scores were taken 3 d/wk to assess incidence and severity of diarrhea. One pig/pen close to pen average was bled for plasma metabolites on days 7 and 49 and subsequently euthanized for spleen and liver weight, ileal and cecum digesta samples for concentration of short-chain fatty acids (SCFA). The concentration of crude protein, crude fat, and non-fiber carbohydrates in biomass was 36.4%, 9.6%, and 50.8% DM, respectively. Inclusion of tended ( = 0.06) to linearly reduce ADG from days 8 through 49 resulting in a trend ( = 0.06) for linear reduction in the final BW. The final BW was 79.0, 79.2, 76.8, and 75.5 kg for the 0%, 2.5%, 3.75%, and 5.0% , respectively. Diets had no effect ( > 0.10) on ADFI, G:F, spleen, and liver weight throughout the entire experiment. On day 7, there was cubic ( = 0.03) decrease and quadratic ( = 0.02) increase in plasma concentration of creatinine and urea N, respectively. However, there were no ( > 0.10) diet effects on plasma metabolites on day 49. There was a tendency ( = 0.08) for linear increase in cecum digesta concentration of acetic acid. There were no diet effects ( > 0.10) on fecal score in the first 4 wk of feeding. In conclusion, feeding yeast tended to depress growth and stimulate cecum fermentation at higher dose and had no detrimental effects on organ weights or plasma metabolites in growing pigs.
PubMed: 32904991
DOI: 10.1093/tas/txaa152 -
Journal of Dairy Science Oct 2022Bovine mastitis, a major infectious disease affecting milking cows, leads to reduced milk yield and quality, reduced animal welfare, and an increased need for culling....
Bovine mastitis, a major infectious disease affecting milking cows, leads to reduced milk yield and quality, reduced animal welfare, and an increased need for culling. Although its major causative agents are bacteria, yeast species and achlorophyllous algae of the Prototheca genus are well known as causative agents of bovine refractory mastitis. Nevertheless, few studies have analyzed specific yeasts and Prototheca in this context. Herein, we present survey data of yeast species and Prototheca species isolated from bulk tank milk in the Tokachi district of Japan from April 2020 through March 2021. The species of 276 isolates were determined. Yeast species accounted for 184 isolates, of which Pichia kudriavzevii was the most prevalent species. Regarding Prototheca species, only Prototheca bovis was isolated (92 isolates). Prototheca bovis and Pichia kudriavzevii were detected throughout the year and were detected repeatedly on the same farm. Kluyveromyces marxianus was the second most frequently isolated yeast species after Pichia kudriavzevii. Candida parapsilosis, the fourth most frequently isolated yeast species, was found discontinuously. Analysis of monthly data indicated that Kluyveromyces marxianus and Candida parapsilosis were mainly found during the winter and summer months, respectively. Candida akabanensis and Pichia cactophila were the third and fifth most frequently isolated yeast species, respectively. They were detected repeatedly in bulk tank milk samples from the same farms. Results obtained from bulk tank milk underscore the prevalence of these species. These study results are expected to contribute to the elucidation of problematic yeast and Prototheca species.
Topics: Animals; Cattle; Cattle Diseases; Female; Japan; Kluyveromyces; Mastitis, Bovine; Milk; Phylogeny; Pichia; Prototheca
PubMed: 35965121
DOI: 10.3168/jds.2022-21781 -
ELife Apr 2021Bacterial members of the infant gut microbiota and bacterial-derived short-chain fatty acids (SCFAs) have been shown to be protective against childhood asthma, but a...
Bacterial members of the infant gut microbiota and bacterial-derived short-chain fatty acids (SCFAs) have been shown to be protective against childhood asthma, but a role for the fungal microbiota in asthma etiology remains poorly defined. We recently reported an association between overgrowth of the yeast in the gut microbiota of Ecuadorian infants and increased asthma risk. In the present study, we replicated these findings in Canadian infants and investigated a causal association between early life gut fungal dysbiosis and later allergic airway disease (AAD). In a mouse model, we demonstrate that overgrowth of within the neonatal gut exacerbates features of type-2 and -17 inflammation during AAD later in life. We further show that growth and adherence to gut epithelial cells are altered by SCFAs. Collectively, our results underscore the potential for leveraging inter-kingdom interactions when designing putative microbiota-based asthma therapeutics.
Topics: Animals; Asthma; Bacteria; Bacterial Physiological Phenomena; Case-Control Studies; Child; Child, Preschool; Gastrointestinal Microbiome; Humans; Infant; Mice, Inbred C57BL; Pichia; Specific Pathogen-Free Organisms; Mice
PubMed: 33876729
DOI: 10.7554/eLife.67740 -
Journal of Hazardous Materials Mar 2019The toxicity of cadmium (Cd) is the major limitation to its removal using microorganisms. The Cd tolerance of Pichia kudriavzevii was obviously enhanced by acid stress...
The toxicity of cadmium (Cd) is the major limitation to its removal using microorganisms. The Cd tolerance of Pichia kudriavzevii was obviously enhanced by acid stress based on multi-stress cross-protection. RNA-Seq showed that most differentially expressed genes (DEGs) in the Pentose phosphate pathway, Citrate cycle (TCA cycle), Glycolysis/Gluconeogenesis, Peroxisome and Glutathione metabolism were up-regulated by acid stress. The up-regulated expression of genes related to ATP synthesis (GOR1, ALD5, ADH4, ADH6, MDH2, IDH1, IDH2, and ATP19) and Cd transport (GSTY2, GTO2, GLO2, and YOR1), and the improvement of intracellular GSH level and GST activity, reduced the Cd toxicity towards P. kudriavzevii. Cd efflux by YOR1 played a key role in the decline of intracellular Cd level. Acid stress obviously improved the gene expression levels and activities of antioxidant enzymes (SOD, POD, and CAT), which inhibited the Cd-induced ROS outburst and oxidative damage of proteins and membrane lipids. In addition, the enhanced expression of HSP12 protected P. kudriavzevii from the damage of Cd stress. These results provide some important clues to reconstruct robust strains using for Cd removal in aquatic environments.
Topics: Antioxidants; Biological Transport; Cadmium; Pichia; Stress, Physiological
PubMed: 30513442
DOI: 10.1016/j.jhazmat.2018.11.101