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International Journal of Food... Dec 2022With the aim to reveal the microbial community succession at various temperatures in the fermentation of Qingzhuan tea (QZT), the Illumina NovaSeq sequencing was carried...
With the aim to reveal the microbial community succession at various temperatures in the fermentation of Qingzhuan tea (QZT), the Illumina NovaSeq sequencing was carried out to analyze bacterial and fungal community structure in tea samples collected from the fermentation set at various temperatures, i.e., 25 °C, 30 °C, 37 °C, 45 °C, 55 °C, and room temperature. The results showed that fermentation temperature profoundly affected the microbial community succession in the QZT fermentation. Microbial richness and community diversity decreased along with the increase of fermentation temperature. Despite the differences between microorganisms and their metabolic types among various temperatures, most bacteria and fungi showed positive correlations at the genera level. Klebsiella, Paenibacillus, Cohnella, and Pantoea were confirmed as the main bacterial genera, and Aspergillus and Cyberlindnera were the main fungal genera in QZT fermentation. The microbial genera (i.e. Aspergillus, Rhizomucor, Thermomyces, Ralstonia, Castellaniella, and Vibrio) were positively correlated with fermentation temperature (P < 0.05), while Klebsiella, Paenibacillus, and Aspergillus had good adaptability at different temperatures. Conversely, Pantoea and Cyberlindnera were only suitable for low temperature (≤37 °C) growth, and Thermomyces was only suitable for high temperature (>37 °C) growth. Aspergillus had a significant positive correlation with tea aroma quality (r = 0.64, p < 0.05). This study would help to understand the formation mechanism of QZT from microflora perspective.
Topics: Aspergillus; Bacteria; Fermentation; Microbiota; Tea; Temperature
PubMed: 36155261
DOI: 10.1016/j.ijfoodmicro.2022.109937 -
Journal of Fungi (Basel, Switzerland) Jul 2022Standardized, reproducible and validated Mucorales quantitative PCR (qPCR) assays are needed in the context of routine testing in diagnostic labs. We, therefore,...
Standardized, reproducible and validated Mucorales quantitative PCR (qPCR) assays are needed in the context of routine testing in diagnostic labs. We, therefore, compared the commercial MucorGenius assay (PathoNostics, Maastricht) targeting five genera of Mucorales to our in-house qPCR targeting spp., spp. and spp. To assess their analytical sensitivity, 25 frozen leftover serum specimens, which had already tested positive based on our in-house assay, were selected. These sera were from 15 patients with probable or proven mucormycosis. For analytical specificity, 0.5 pg from 15 purified fungal DNAs from nine different Mucorales genera were spiked into pooled qPCR-negative leftover serum specimens. All samples were tested in parallel with both assays and the quantitative cycles (Cq) were compared. A total of 13/25 (52%) serum samples were amplified by one of the two assays with only four of them detected with the MucorGenius assay. In spiked specimens, all targeted strains were successfully amplified by our in-house qPCR. The MucorGenius assay was not able to detect but successfully amplified all other species targeted by the kit and two additional non-targeted species ( and ). The MucorGenius assay showed lower analytical sensitivity compared to our in-house assay. Indeed, the MucorGenius assay amplified more species, as expected, but showed a decreased detection of the frequent species .
PubMed: 36012775
DOI: 10.3390/jof8080786 -
EFSA Journal. European Food Safety... Aug 2022The food enzyme mucorpepsin (EC 3.4.23.23) is produced with the non-genetically modified strain DSM 29547 by Chr. Hansen. The food enzyme is free from viable cells of...
The food enzyme mucorpepsin (EC 3.4.23.23) is produced with the non-genetically modified strain DSM 29547 by Chr. Hansen. The food enzyme is free from viable cells of the production organism. It is intended to be used in dairy processing for cheese production. The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.26 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not indicate a safety concern. The systemic toxicity was assessed by a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 618 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, results in a margin of exposure of at least 2,400. A search for similarity of the amino acid sequence of the food enzyme to known allergens was made and three matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions by dietary exposure cannot be excluded but is considered low except for individuals sensitised to mustard proteins, but this risk will not exceed that of mustard consumption. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns, under the intended conditions of use.
PubMed: 35978613
DOI: 10.2903/j.efsa.2022.7457 -
Infection and Drug Resistance 2022Long-term chemotherapy and immunosuppressants in acute myeloid leukaemia (AML) patients can result in a high risk of opportunistic infections. is an opportunistic...
Long-term chemotherapy and immunosuppressants in acute myeloid leukaemia (AML) patients can result in a high risk of opportunistic infections. is an opportunistic pathogen that exists in nature, but infection caused by is rare in the clinic. Notably, the sensitivity and detection time of conventional diagnostic tools for this fungus usually falls short of the needs of clinical diagnosis, resulting in treatment failure. Currently, metagenomics next-generation sequencing (mNGS) has played an important role in the detection of pathogens. Here, we report a case of pneumonia in a haematopoietic stem cell transplantation (HSCT) patient, detected by the mNGS method.
PubMed: 35965849
DOI: 10.2147/IDR.S376045 -
Journal of Bioscience and Bioengineering Oct 2022Endo-β-N-acetylglucosaminidase (ENGase) is an enzyme that hydrolyzes the chitobiose core of N-glycans and is widely used for glycan analysis on glycoproteins and...
Endo-β-N-acetylglucosaminidase (ENGase) is an enzyme that hydrolyzes the chitobiose core of N-glycans and is widely used for glycan analysis on glycoproteins and preparation of precursors for glycosylated compounds. While most of the ENGases that can hydrolyze complex-type glycans are derived from eukaryotes, their production by heterologous expression using Escherichia coli is insufficient, making the production process expensive. From an industrial perspective, there is a need for a less expensive enzyme with higher activity and stability. In this study, we identified a novel ENGase gene from a thermophilic fungus, Rhizomucor pusillus, and named it Endo-Rp. Characterization of the recombinant Endo-Rp showed that the enzyme had maximum hydrolytic activity at 60 °C and hydrolyzed high-mannose-type and biantennary complex-type glycans, but not (2,4)-branched triantennary complex-type or fucosylated glycans. Endo-Rp also hydrolyzed N-glycans attached to RNase B and human transferrin. In summary, we consider Endo-Rp to be a valuable enzyme in various scientific and industrial applications.
Topics: Acetylglucosaminidase; Glycoproteins; Humans; Mannose; Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; Polysaccharides; Transferrins
PubMed: 35961816
DOI: 10.1016/j.jbiosc.2022.06.013 -
EFSA Journal. European Food Safety... Aug 2022The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164. The enzyme is chemically...
The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164. The enzyme is chemically modified by DuPont Nutrition Biosciences (now IFF) to produce a thermolabile form. The food enzyme is free from viable cells of the production organism. It is intended to be used in milk processing for cheese production. The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.98 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,320 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 1,300. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched and five matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but is considered low except for individuals sensitised to mustard proteins, but this risk will not exceed that of mustard consumption. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
PubMed: 35949932
DOI: 10.2903/j.efsa.2022.7460 -
Food Research International (Ottawa,... Sep 2022Modernized mechanization and intelligent transformation are the trends of Chinese baijiu industry development. However, these changes affect the operational environment,...
Modernized mechanization and intelligent transformation are the trends of Chinese baijiu industry development. However, these changes affect the operational environment, which lead to the decreased metabolism of esters during baijiu fermentation, especially for ethyl lactate. Ethyl lactate is an important flavor compound in most types of baijiu, which is mainly produced by esterification of lactic acid and ethanol. However, considerably less is known about the dynamic microbial succession related to ethyl lactate metabolism during the modernized baijiu fermentation process. In this study, we investigated the lactic acid bacteria, yeast and mold community succession and ethyl lactate metabolism during baijiu fermentation. Results showed that fermentation mode had a significant effect on lactic acid and ethyl lactate metabolism (p < 0.001). Specifically, the accumulation of lactic acid in modernized process was 50% lower than that in traditional process (23.22 ± 7.41 g/kg versus 33.92 ± 2.32 g/kg fermented grains). The accumulation of ethyl lactate in the modernized baijiu fermentation process (9.46 ± 1.78 g/kg fermented grains) was significantly lower than that in traditional baijiu fermentation process (37.10 ± 5.86 g/kg fermented grains). Moreover, Illumina Miseq sequencing showed 11 lactic acid bacteria OTUs, 6 yeast OTUs and 4 mold OTUs were abundant during fermentation. Compared with traditional baijiu fermentation process, modernized process led to more Lactobacillus and Candida, but less Pichia, Aspergillus, Rhizomucor and Rhizopus during fermentation. Based on the redundancy analysis and correlation network analysis, our study showed the metabolism of ethyl lactate mainly related to the activities of Pichia, Aspergillus, Rhizomucor and Rhizopus, especially for Rhizomucor and Rhizopus. This study revealed that the regulation of Pichia, Aspergillus, Rhizomucor Rhizopus and Candida might be an effective orientation for adjusting the metabolism of ethyl lactate during modernized baijiu fermentation.
Topics: China; Fermentation; Lactates; Lactic Acid; Microbiota; Pichia; Saccharomyces cerevisiae
PubMed: 35940782
DOI: 10.1016/j.foodres.2022.111566 -
Food Research International (Ottawa,... Sep 2022Daqu, the fermentation starter of Chinese baijiu, is produced by barley and/or peas during open fermentation using natural inoculation. However, the succession of...
Daqu, the fermentation starter of Chinese baijiu, is produced by barley and/or peas during open fermentation using natural inoculation. However, the succession of microbial communities and their roles during daqu manufacture remain unclear, which are closely related to the flavor and quality of baijiu. In this study, the dynamics of physicochemical properties, microbial communities, and volatile compounds were investigated at both fermentation (FM) and storage (ST) stages during the manufacture of Nongxiangxing daqu. High-throughput sequencing analysis showed that Weissella and Lactobacillus were the predominant bacterial genera, at the end of storage, the proportion was 31.45% and 13.14% respectively. Thermoascus, Rhizopus, Pichia and Rhizomucor were dominant fungi in daqu, and Thermoascus, Pichia and Rhizopus still occupied a large proportion at the end of daqu storage, accounting for 67.65%, 23.94% and 7.05% respectively. Redundancy analysis was employed to investigate the relationship between microorganisms and physicochemical indexes, and the results showed that acidity and Lactobacillus were positively correlated, saccharification power was positively correlated with Aspergillus, Rhizomucor, Rasamsonia and Thermoascu. The correlation networks between microorganisms and volatile substances were analyzed, a total of 60 compounds including 42 esters, 4 alcohols, 5 ketones and 5 aldehydes, 2 acids, 1 amine, 1 pyrazine were detected, the results suggested that esters are the main aroma components in daqu, and most of esters are positively correlated with fungi. In addition, key enzymes involved in carbohydrate hydrolysis, ethanol fermentation, and flavor formation were revealed. This study may further improve our understanding concerning the microbial system and microbial roles of Nongxiangxing daqu and may contribute to optimize the process during daqu manufacture.
Topics: Alcoholic Beverages; Bacteria; Esters; Lactobacillus; Microbiota; Pichia
PubMed: 35940779
DOI: 10.1016/j.foodres.2022.111559 -
EFSA Journal. European Food Safety... Aug 2022The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164 by Takabio. The enzyme is...
The food enzyme mucorpepsin (aspartic endopeptidase, EC 3.4.23.23) is produced with the non-genetically modified microorganism strain MMR 164 by Takabio. The enzyme is chemically modified to produce a thermolabile form. The food enzyme is free from viable cells of the production organism. It is intended to be used in milk processing for cheese production. The dietary exposure to the food enzyme-total organic solids (TOS) was estimated to be up to 0.98 mg TOS/kg body weight (bw) per day in European populations. Genotoxicity tests did not raise a safety concern. The systemic toxicity was assessed by means of a repeated dose 90-day oral toxicity study in rats. The Panel identified a no observed adverse effect level of 1,320 mg TOS/kg bw per day, the highest dose tested, which when compared with the estimated dietary exposure, resulted in a margin of exposure of at least 1,300. Similarity of the amino acid sequence of the food enzyme to those of known allergens was searched and five matches were found. The Panel considered that, under the intended conditions of use, the risk of allergic sensitisation and elicitation reactions upon dietary exposure to this food enzyme cannot be excluded, but is considered low except for individuals sensitised to mustard proteins, but this risk will not exceed that of mustard consumption. Based on the data provided, the Panel concluded that this food enzyme does not give rise to safety concerns under the intended conditions of use.
PubMed: 35936946
DOI: 10.2903/j.efsa.2022.7459 -
Molecules (Basel, Switzerland) Jul 2022Four commercial immobilized lipases biocatalysts have been submitted to modifications with different metal (zinc, cobalt or copper) phosphates to check the effects of...
Four commercial immobilized lipases biocatalysts have been submitted to modifications with different metal (zinc, cobalt or copper) phosphates to check the effects of this modification on enzyme features. The lipase preparations were LipozymeTL (TLL-IM) (lipase from ), Lipozyme435 (L435) (lipase B from ), LipozymeRM (RML-IM), and LipuraSelect (LS-IM) (both from lipase from ). The modifications greatly altered enzyme specificity, increasing the activity versus some substrates (e.g., TLL-IM modified with zinc phosphate in hydrolysis of triacetin) while decreasing the activity versus other substrates (the same preparation in activity versus - or - methyl mandelate). Enantiospecificity was also drastically altered after these modifications, e.g., LS-IM increased the activity versus the isomer while decreasing the activity versus the isomer when treated with copper phosphate. Regarding the enzyme stability, it was significantly improved using octyl-agarose-lipases. Using all these commercial biocatalysts, no significant positive effects were found; in fact, a decrease in enzyme stability was usually detected. The results point towards the possibility of a battery of biocatalysts, including many different metal phosphates and immobilization protocols, being a good opportunity to tune enzyme features, increasing the possibilities of having biocatalysts that may be suitable for a specific process.
Topics: Copper; Enzymes, Immobilized; Fungal Proteins; Lipase; Phosphates; Salts
PubMed: 35889359
DOI: 10.3390/molecules27144486