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12 pages, 978 KiB

Open AccessArticle

Bioprocess Integration of Candida ethanolica and Chlorella vulgaris for Sustainable Treatment of Organic Effluents in the Honey Industry

by Juan Gabriel Sánchez Novoa, Natalia Rodriguez, Tomás Debandi, Juana María Navarro Llorens, Laura Isabel de Cabo and Patricia Laura Marconi

Sustainability 2025, 17(15), 6809; https://doi.org/10.3390/su17156809 - 27 Jul 2025

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Abstract

Honey processing is closely linked to water pollution due to the lack of a specific wastewater treatment. This study proposes a sustainable and innovative solution based on two sequential bioprocesses using a real effluent from an Argentine honey-exporting facility. In the initial stage, the honey wastewater was enriched with a non-Saccharomyces yeast (Candida ethanolica), isolated from the same effluent. Treatment with this yeast in a bioreactor nearly doubled the total sugar removal efficiency compared to the control (native flora). Subsequent clarification with diatomaceous earth reduced the optical density (91.6%) and COD (30.9%). In the second stage, secondary sewage effluent was added to the clarified effluent and inoculated with Chlorella vulgaris under different culture conditions. The best microalgae performance was observed under high light intensity and high inoculum concentration, achieving a fivefold increase in cell density, a specific growth rate of 0.752 d⁻¹, and a doubling time of 0.921 d. Although total sugar removal in this stage remained below 28%, cumulative COD removal reached 90% after nine days under both lighting conditions. This study presents the first integrated treatment approach for honey industry effluents using a native yeast–microalgae system, incorporating in situ effluent recycling and the potential for dual waste valorization. Full article

(This article belongs to the Special Issue Research on Sustainable Wastewater Treatment)

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12 pages, 2969 KiB

Open AccessArticle

Addressing the Concern of Orange-Yellow Fungus Growth on Palm Kernel Cake: Safeguarding Dairy Cattle Diets for Mycotoxin-Producing Fungi

by Carlos Bastidas-Caldes, David Vasco-Julio, Maria Huilca-Ibarra, Salomé Guerrero-Freire, Yanua Ledesma-Bravo and Jacobus H. de Waard

Microorganisms 2024, 12(5), 937; https://doi.org/10.3390/microorganisms12050937 - 5 May 2024

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Abstract

Palm kernel cake (PKC), a byproduct of palm oil extraction, serves an important role in Ecuador’s animal feed industry. The emergence of yellow-orange fungal growth in PKC on some cattle farms in Ecuador sparked concerns within the cattle industry regarding a potential mycotoxin-producing fungus on this substrate. Due to the limited availability of analytical chemistry techniques in Ecuador for mycotoxin detection, we chose to isolate and identify the fungus to determine its association with mycotoxin-producing genera. Through molecular identification via ITS region sequencing, we identified the yellow-orange fungus as the yeast Candida ethanolica. Furthermore, we isolated two other fungi—the yeast Pichia kudriavzevii, and the fungus Geotrichum candidum. Molecular identification confirmed that all three species are not classified as mycotoxin-producing fungi but in contrast, the literature indicates that all three have demonstrated antifungal activity against Aspergillus and Penicillium species, genera associated with mycotoxin production. This suggests their potential use in biocontrol to counter the colonization of harmful fungi. We discuss preventive measures against the fungal invasion of PKC and emphasize the importance of promptly identifying fungi on this substrate. Rapid recognition of mycotoxin-producing and pathogenic genera holds the promise of mitigating cattle intoxication and the dissemination of mycotoxins throughout the food chain. Full article

(This article belongs to the Special Issue Food Microbiota and Food Safety)

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16 pages, 2415 KiB

Open AccessArticle

Enhancing the Content of Hesperidin and Nobiletin in Citrus Wines through Multi-Strain Fermentation

by Shaoqing Zou, Yerui Ouyang, Linfeng Xie, Jiantao Liu, Ya Wang, Yiwen Xiao, Boliang Gao and Du Zhu

Fermentation 2024, 10(5), 238; https://doi.org/10.3390/fermentation10050238 - 29 Apr 2024

Cited by 1 | Viewed by 1970

Abstract

This research investigates how different fermentation techniques using non-Saccharomyces yeast (Candida ethanolica Ce, Hanseniaspora guilliermondii Hg, Hanseniaspora thailandica Ht) and Saccharomyces cerevisiae (Sc) affect the synthesis of hesperidin, nobiletin, and other flavonoid and aromatic substances, which play a vital role in improving the overall quality of fruit wines due to their various biological properties. The combination of Sc:(Ce.Ht)-1:100 (Ce 0.5 × 10⁷ CFU/mL, Ht 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁵ CFU/mL) yielded the highest hesperidin content at 4.12 ± 0.08 mg/L, followed by the Sc:(Ce.Hg)-1:1 (Ce 0.5 × 10⁷ CFU/mL, Hg 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁷ CFU/mL) combination at 4.08 ± 0.06 mg/L. The highest nobiletin content was achieved by the (Hg.Ht)-10-Sc (Hg 0.5 × 10⁷ CFU/mL, Ht 0.5 × 10⁷ CFU/mL, Sc 1 × 10⁷ CFU/mL) combination, reaching 1.04 ± 0.05 mg/L, which was significantly higher than other multi-strain combinations. Additionally, the hesperidin content produced by the (Hg.Ht)-10-Sc combination was relatively high at 4.04 ± 0.02 mg/L, demonstrating a richness and complexity of aroma superior to that of fermentation with commercial yeast strains alone. The findings suggest that the (Hg.Ht)-10-Sc combination is the most effective multi-strain combination for increasing the levels of nobiletin and hesperidin in citrus wine, thereby enhancing the overall quality of the wine. These experimental results offer a promising approach for enhancing the quality of citrus wines and other fruit wines. Full article

(This article belongs to the Section Fermentation for Food and Beverages)

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14 pages, 2346 KiB

Open AccessArticle

The Screening and Isolation of Ethyl-Carbamate-Degrading Strains from Fermented Grains and Their Application in the Degradation of Ethyl Carbamate in Chinese Baijiu

by Siyu Xue, Naihui Dong, Kexin Xiong, Hui Guo, Yiwei Dai, Huipeng Liang, Yingxi Chen, Xinping Lin, Beiwei Zhu and Sufang Zhang

Foods 2023, 12(15), 2843; https://doi.org/10.3390/foods12152843 - 27 Jul 2023

Cited by 9 | Viewed by 1954

Abstract

Ethyl carbamate (EC), a 2A carcinogen produced during the fermentation of foods and beverages, primarily occurs in distilled spirits. Currently, most studies focus on strategies for EC mitigation. In the present research, we aimed to screen strains that can degrade EC directly. Here, we report two Candida ethanolica strains (J1 and J116), isolated from fermented grains, which can reduce EC concentrations directly. These two yeasts were grown using EC as the sole carbon source, and they grew well on different carbon sources. Notably, after immobilization with chitosan, the two strains degraded EC in Chinese Baijiu by 42.27% and 27.91% in 24 h (from 253.03 ± 9.89 to 146.07 ± 1.67 and 182.42 ± 5.05 μg/L, respectively), which was better than the performance of the non-immobilized strains. Furthermore, the volatile organic compound content, investigated using gas chromatography-mass spectrometry, did not affect the main flavor substances in Chinese Baijiu. Thus, the yeasts J1 and J116 may be potentially used for the treatment and commercialization of Chinese Baijiu. Full article

(This article belongs to the Special Issue Research Progress of Yeasts and Molds in Fermented Food Production)

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17 pages, 3281 KiB

Open AccessArticle

Use of Non-Saccharomyces Yeast Co-Fermentation with Saccharomyces cerevisiae to Improve the Polyphenol and Volatile Aroma Compound Contents in Nanfeng Tangerine Wines

by Ahui Xu, Yiwen Xiao, Zhenyong He, Jiantao Liu, Ya Wang, Boliang Gao, Jun Chang and Du Zhu

J. Fungi 2022, 8(2), 128; https://doi.org/10.3390/jof8020128 - 27 Jan 2022

Cited by 45 | Viewed by 4680

Abstract

This study attempted to improve the polyphenol and volatile aroma compound contents in Nanfeng tangerine wines using non-Saccharomyces yeast and Saccharomyces cerevisiae. The effects of fermentation with pure cultures of Candida ethanolica, Hanseniaspora guilliermondii and Hanseniaspora thailandica, as well as in sequential and mixed inoculations (1:1 or 1:100 ratio) with S. cerevisiae in Nanfeng tangerine wines were evaluated. C. ethanolica was found to produce the most polyphenols (138.78 mg/L) during pure fermentation, while H. guilliermondii produced the most volatile aroma compounds (442.34 mg/L). The polyphenol content produced during sequential fermentation with S. cerevisiae and H. guilliermondii (140.24 mg/L) or C. ethanolica (140.21 mg/L) was significantly higher than other co-fermentations. Meanwhile, the volatile aroma compounds were found to be more abundant in S. cerevisiae/H. guilliermondii mixed fermentation (1:1 ratio) (588.35 mg/L) or S. cerevisiae/H. guilliermondii sequential fermentation (549.31 mg/L). Thus, S. cerevisiae/H. guilliermondii sequential fermentation could considerably boost the polyphenol and volatile aroma component contents in Nanfeng tangerine wines. The findings of this study can be used to drive strategies to increase the polyphenol content and sensory quality of tangerine wines and provide a reference for selecting the co-fermentation styles for non-Saccharomyces yeast and S. cerevisiae in fruit wine fermentation. Full article

(This article belongs to the Special Issue Yeasts Applications in Alcohol Production)

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13 pages, 3645 KiB

Open AccessArticle

The Use of MALDI-TOF Mass Spectrometry to Analyze Commensal Oral Yeasts in Nursing Home Residents

by Jang-Jih Lu, Hsiu-Jung Lo, Chih-Hua Lee, Mei-Jun Chen, Chih-Chao Lin, Yin-Zhi Chen, Ming-Horng Tsai and Shao-Hung Wang

Microorganisms 2021, 9(1), 142; https://doi.org/10.3390/microorganisms9010142 - 9 Jan 2021

Cited by 11 | Viewed by 4080

Abstract

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a rapid and accurate method to identify microorganisms in clinical laboratories. This study isolates yeast-like microorganisms in the oral washes that are collected from non-bedridden nursing home residents, using CHROMagar Candida plates, and identifies them using Bruker MALDI-TOF MS. The ribosomal DNA sequences of the isolates are then examined. Three hundred and twenty yeast isolates are isolated from the oral washes. Candida species form the majority (78.1%), followed by Trichosporon/Cutaneotrichosporon species (8.8%). Bruker MALDI-TOF MS gives a high-level confidence, with a log(score) value of ≥1.8, and identifies 96.9% of the isolates. There are six inconclusive results (1.9%), and those sequences are verified as rare clinical species, including Candida ethanolica, Cutaneotrichosporon jirovecii, Exophiala dermatitidis, and Fereydounia khargensis. Almost all of the isolates have a regular color on the CHROMagar Candida plates. If the colonies are grouped by color on the plates, a specific dominant yeast species is present in each color group, except for purple or orange isolates. In conclusion, MALDI-TOF MS is verified as a fast, accurate and practical method to analyze oral yeasts in elderly subjects. Full article

(This article belongs to the Section Systems Microbiology)

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