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1.
Molecules ; 26(20)2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-34684821

RESUMO

Currently, there is a growing demand for flavorings, especially of natural origin. It is worth paying attention to the biotechnological processes of flavor production, characterized by simplicity, high efficiency and relatively low cost. In this study, we analyzed the ability of the Galac tomyces geotrichum mold to transform by-products of the dairy industry: sour whey and buttermilk to complex flavour mixtures with pleasant, honey-rose aroma. Furthermore, the aroma complexity of the fermentation product has been carefully identified applying a sensomic approach involving the use of gas chromatography-olfactometry (GC-O), gas chromatography-mass spectrometry (GC-MS) and stable isotope dilution assay (SIDA) to identify and quantify aroma compounds. Based on the calculation of odor activity value (OAV), 13 key aroma compounds were present in both tested variants. The highest OAVs were found for phenylacetaldehyde (honey-like) in the buttermilk variant (912) and 2-phenylethanol (rose-like) in the sour whey variant (524). High values of this indicator were also recorded for phenylacetaldehyde (319) and 3-methyl-1-butanol with a fruity aroma (149) in the sour whey culture. The other compounds identified are 3-methylbutanal (malty), 2,3-butanedione (cheesy), isovaleric acid (cheesy), 3-(methylthio)-propanal (boiled potato), butanoic acid (vinegar), (E)-2-nonenal (fatty), ethyl furaneol (burnt sugar), dimethyl trisulfide (cabbage), and acetic acid (vinegar).


Assuntos
Leitelho/análise , Leitelho/microbiologia , Microbiologia de Alimentos , Geotrichum/metabolismo , Odorantes/análise , Soro do Leite/química , Soro do Leite/microbiologia , Acetaldeído/análogos & derivados , Acetaldeído/análise , Biotecnologia , Biotransformação , Fermentação , Aromatizantes/metabolismo , Tecnologia de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Olfatometria , Álcool Feniletílico/análise , Paladar , Compostos Orgânicos Voláteis/análise
2.
Int J Food Microbiol ; 345: 109130, 2021 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-33735781

RESUMO

Pélardon is an artisanal French raw goat's milk cheese, produced using natural whey as a backslop. The aim of this study was to identify key microbial players involved in the acidification and aroma production of this Protected Designation of Origin cheese. Microbial diversity of samples, collected from the raw milk to 3-month cheese ripening, was determined by culture-dependent (MALDI-TOF analysis of 2877 isolates) and -independent (ITS2 and 16S metabarcoding) approaches and linked to changes in biochemical profiles (volatile compounds and acids). In parallel, potential dominant autochthonous microorganism reservoirs were also investigated by sampling the cheese-factory environment. Complex and increasing microbial diversity was observed by both approaches during ripening although major discrepancies were observed regarding Lactococcus lactis and Lacticaseibacillus paracasei fate. By correlating microbial shifts to biochemical changes, Lactococcus lactis was identified as the main acidifying bacterium, while L. mesenteroides and Geotrichum candidum were prevalent and associated with amino acids catabolism after the acidification step. The three species were dominant in the whey (backslop). In contrast, L. paracasei, Enterococcus faecalis, Penicillium commune and Scopulariopsis brevicaulis, which dominated during ripening, likely originated from the cheese-making environment. All these four species were positively correlated to major volatile compounds responsible for the goaty and earthy Pélardon cheese aroma. Overall, this work highlighted the power of MALDI-TOF and molecular techniques combined with volatilome analyses to dynamically follow and identify microbial communities during cheese-making and successively identify the key-players involved in aroma production and contributing to the typicity of Pélardon cheese.


Assuntos
Bactérias/classificação , Bactérias/metabolismo , Queijo/microbiologia , Fungos/classificação , Fungos/metabolismo , Leite/microbiologia , Animais , Bactérias/isolamento & purificação , Enterococcus faecalis/isolamento & purificação , Enterococcus faecalis/metabolismo , Fungos/isolamento & purificação , Geotrichum/isolamento & purificação , Geotrichum/metabolismo , Cabras , Lactobacillus paracasei/isolamento & purificação , Lactobacillus paracasei/metabolismo , Lactococcus lactis/isolamento & purificação , Lactococcus lactis/metabolismo , Microbiota , Odorantes/análise , Penicillium/isolamento & purificação , Penicillium/metabolismo , Scopulariopsis/isolamento & purificação , Scopulariopsis/metabolismo , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
3.
Food Chem ; 346: 128804, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-33418411

RESUMO

Fruity beers can be promoted through production of flavoring compounds during fermentation by partial replacement of brewing yeast by non-conventional-yeasts with high aroma production abilities. We evaluated here the use of a wild Saprochaete suaveolens strain, producing atypical aroma compounds, to produce new natural fruity beer, while keeping classical production conditions used in brewing industry. S. suaveolens was inoculated as starter of culture during beer fermentation and the fermentation performance was evaluated through measurement of several physicochemical parameters. The aroma profile of the engineered beers was monitored using HS-SPME GC/MS. The results showed that high fruity aroma and low-ethanol content beers were obtained through single-fermentation using S. suaveolens. We also demonstrated that during mixed-fermentation, S. suaveolens maintained high metabolic activity and allowed production of beer enriched with fruity aroma. Production of high or low ethanol content fruity beer could be achieved by varying the composition of the starter of culture.


Assuntos
Fermentação , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/metabolismo , Cerveja/análise , Aromatizantes/análise , Frutas/química , Geotrichum/metabolismo , Odorantes/análise
4.
Lett Appl Microbiol ; 72(4): 445-457, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33278831

RESUMO

Textile effluent is generally complicated to manage because of its extremely noxious and recalcitrant coloured compositions. Mycoremediation is an extensively used strategy for the competent degradation of hazardous pollutants present in textile effluent. Fungus could be immobilized in synthetic or natural matrices. The current study shows the decolourization of the textile effluent by 85·5 and 98·5% within 6 h using suspended and immobilized fungus, Geotrichum candidum with optimized parameters like inoculum size (5%), pH (4·5), and temperature (30°C). To maintain a high biomass of fungal population and enhance the retention of fungal strain in the contaminated sites, the fungi need to be immobilized. Hence, the fungus was immobilized naturally onto the selected inert support that is, coconut fibres by the means of adsorption, where they grew as active films on the fibres after being grown in the culture broth. The optimized process parameters of inoculum size, fibre quantity and agitation speed for immobilized G. candidum were 5%, 2·2 g l-1 of effluent and 100 rev min-1 respectively. High level of laccase (22 and 25 U l-1 in suspended and immobilized fungal cells treatment respectively) was observed during the process of decolourization and it was found that decolourization was directly proportional to the laccase activity. The UV-vis, FTIR, 1 H NMR and GC-MS analyses of treated textile industrial wastewater revealed the degradation of toxic pollutants in the textile effluent and formation of lower molecular weight intermediates. The study revealed a higher efficacy of immobilized G. candidum in comparison to suspended fungal culture, employing ligninolytic enzyme laccase, which catalyzes the degradation/transformation of aromatic dyes in the textile effluent thus decolourizing it.


Assuntos
Biodegradação Ambiental , Corantes/metabolismo , Geotrichum/metabolismo , Águas Residuárias/química , Purificação da Água/métodos , Resíduos Industriais/análise , Lacase/metabolismo , Têxteis
5.
J Sci Food Agric ; 101(4): 1709-1714, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-32844441

RESUMO

BACKGROUND: Lignocellulosic wastes are pretreated prior to their utilization in fermentation processes. Such pretreatment also alters the topological features of the substrates, and therefore the suitability of pretreated waste as immobilization matrix for microbial cells needs investigation. RESULTS: In this study, the effect of chemical pretreatment of sugarcane bagasse (SB) for its subsequent utilization as a matrix to immobilize a pectinolytic yeast, Geotrichum candidum AA15, was evaluated using cell retention, concentration of immobilized cells, immobilization efficiency, scanning electron microscopy and Fourier transform infrared spectroscopy of the substrate and pectinase titers obtained after recycling. The results revealed that untreated SB is more efficient for immobilization with higher values of cell retention and pectinase productivity (99.78%) retained for up to six production cycles. It was deduced that removal of lignin by pretreatment negatively influenced the ability of SB to support cell adhesion, as lignin acts as a sealing agent that provides strength to the substrate. CONCLUSIONS: The strategy of utilizing SB as immobilization matrix was found effective at the laboratory scale as it improved pectinase production and may be investigated further for large-scale and cost-effective production. © 2020 Society of Chemical Industry.


Assuntos
Celulose/metabolismo , Geotrichum/química , Geotrichum/metabolismo , Lignina/química , Poligalacturonase/biossíntese , Saccharum/microbiologia , Células Imobilizadas/química , Células Imobilizadas/metabolismo , Fermentação , Geotrichum/enzimologia , Hidrólise , Lignina/metabolismo , Saccharum/química , Espectroscopia de Infravermelho com Transformada de Fourier
6.
J Agric Food Chem ; 68(39): 10799-10807, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32865406

RESUMO

Fermented products with a pleasant aroma and with strong honey, rose, and fruit odor notes were developed through the biotransformation of a medium containing sour or sweet whey with the addition of l-phenylalanine by the Galactomyces geotrichum mold. In order to obtain the strong honey-rose aroma, G. geotrichum strains were screened and fermentation conditions were optimized to achieve a preferable ratio (>1) of phenylacetaldehyde to 2-phenylethanol by the Ehrlich pathway. This allowed post-fermentation products with the ratio of concentrations of phenylacetaldehyde to 2-phenylethanol being 1.7:1. Additionally, the use of gas chromatography-olfactometry (GC-O) analysis and the calculation of odor activity values (OAVs) allowed 10 key odorants to be identified in post-fermentation products. The highest OAVs were found for phenylacetaldehyde with a honey odor in both sour and sweet whey cultures (3010 and 1776, respectively). In the variant with sour whey, the following compounds with the highest OAVs were 3-methyl-1-butanol (131), 3-(methylthio)-propanal (119), 3-methylbutanal (90), dimethyl trisulfide (71), 2,3-butanedione (37), and 2-phenylethanol (29). In the post-fermentation product with sweet whey, the following compounds with the highest OAVs were 3-(methylthio)-propanal (112), dimethyl trisulfide (69), and 2,3-butanedione (41).


Assuntos
Geotrichum/metabolismo , Odorantes/análise , Compostos Orgânicos Voláteis/metabolismo , Soro do Leite/metabolismo , Acetaldeído/análogos & derivados , Acetaldeído/análise , Acetaldeído/metabolismo , Cromatografia Gasosa , Fermentação , Geotrichum/química , Olfatometria , Fenilalanina/metabolismo , Compostos Orgânicos Voláteis/química
7.
Bioorg Chem ; 102: 104126, 2020 09.
Artigo em Inglês | MEDLINE | ID: mdl-32736150

RESUMO

Flavonoids are involved in citrus defense against phytopathogens. In this study, we applied in vitro biocatalysis assays using the flavanones glycosides hesperidin and naringin to explore the enzymatic activities involved in such interaction. The main enzymatic activity observed was the hydrolysis catalyzed by fungi naringinases and hesperidinases. Withing 7 days, the two citrus phytopathogenic fungi, Penicillium digitatum and Penicillium italicum, exhibited the highest hydrolyzing rate on the flavanones, reaching conversion values higher than 90%. In addition, Geothrichum citri-aurantii exhibited no enzymatic activity and Penicillium expansum only hydrolyzed hesperidin. In order to evaluate flavonoid biotransformation by the fungi in vivo, citrus fruits infected with P. digitatum were analyzed through molecular networking and Imaging Mass Spectrometry (IMS). In vivo assays revealed that citrus fruit in response to the infection is able to hydroxylate flavonoids, and novel flavonoid structures were associated to the citrus' defense. The data reported here present a new point of view in the relation between citrus flavonoids and phytopathogenic fungi and can be useful to understand the infection processes and host-pathogen interaction.


Assuntos
Antifúngicos/farmacologia , Flavonoides/farmacologia , Geotrichum/efeitos dos fármacos , Glicosídeo Hidrolases/metabolismo , Complexos Multienzimáticos/metabolismo , Penicillium/efeitos dos fármacos , beta-Glucosidase/metabolismo , Antifúngicos/química , Antifúngicos/metabolismo , Citrus/química , Relação Dose-Resposta a Droga , Flavonoides/química , Flavonoides/metabolismo , Geotrichum/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Penicillium/metabolismo , Relação Estrutura-Atividade
8.
Genomics ; 112(6): 4063-4071, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32650101

RESUMO

Sour rot, caused by Geotrichum citri-aurantii, is a major postharvest disease of citrus,and it causes serious economic losses. In this study, a high-quality genome sequence of G. citri-aurantii was obtained by Single Molecule Real-Time Sequencing (SMRT). Approximately 5.43 Gb of clean data were obtained and a total of 27.94-Mb genomic sequence was mapped to 10 chromosome groups after high-through chromosome conformation capture (Hi-C) assembly. In addition, three polygalacturonase genes which were related to pathogenicity in G. citri-aurantii genome were discovered. And transcriptome data of guazatine-resistance had been analyzed, the results showed that the guazatine-resistance of G. citri-aurantii was related to two ATP-binding cassette (ABC) transporter family genes, six major facilitator superfamily (MFS) transporter family genes and two multidrug and toxic compound extrusion (MATE) transporter family genes. In summary, our research may provide novel insights into the effective control of this pathogen.


Assuntos
Citrus/microbiologia , Fungicidas Industriais/farmacologia , Genoma Fúngico , Geotrichum/genética , Guanidinas/farmacologia , Farmacorresistência Fúngica/genética , Perfilação da Expressão Gênica , Genes Fúngicos , Genômica , Geotrichum/efeitos dos fármacos , Geotrichum/metabolismo , Geotrichum/patogenicidade , Proteínas de Membrana Transportadoras/genética , Poligalacturonase/genética
9.
Chemosphere ; 259: 127507, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650171

RESUMO

In this study, a yeast-like fungal strain (LG-8), newly isolated from spontaneous Tibet kefir in China, was identified as Geotrichum candidum on the basis of its morphological characteristics and ITS5.8S gene sequence. Interestingly, the strain was able to remove more than 99% of Pb2+ ions in water at low concentrations and a maximum of 325.68 mg lead/g of dry biomass. The results of selective passivation experiments suggested that phosphate, amide and carboxyl groups on the cell wall contributed to lead removal. Scanning electron microscopy (SEM) photomicrographs revealed that large amounts of micro/nanoparticles formed on the cell wall, and energy dispersive X-ray spectroscopy (EDX) results further indicated the presence of lead along with phosphorus and chlorine in the particles. Furthermore, the results of Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) analyses revealed that the particles were composed of pyromorphite [Pb5(PO4)3Cl], a highly insoluble lead mineral. Importantly, this is the first time that the biomineralization of lead into pyromorphite has been observed as the major mechanism for lead removal by G. candidum LG-8, providing a new strategy to scavenge heavy metals from aquatic environment in an eco-friendly manner.


Assuntos
Geotrichum/isolamento & purificação , Kefir/microbiologia , Chumbo/isolamento & purificação , Leite/microbiologia , Purificação da Água/métodos , Animais , Biomineralização , Geotrichum/metabolismo , Microscopia Eletrônica de Varredura , Minerais/química , Fosfatos/química , Análise Espectral , Tibet
10.
J Appl Microbiol ; 129(6): 1633-1643, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32491245

RESUMO

AIM: The aim of the study is to investigate the efficiency of Geotrichum candidum in the decolourization and mineralization of synthetic azo dyes. METHODS AND RESULTS: It includes screening of enzymes from G. candidum and its optimization, followed by decolourization and mineralization studies. Decolourization was observed to be maximum in methyl orange (94·6%) followed by Congo red (85%), trypan blue (70·4%) and Eriochrome Black T (55·6%) in 48 h, suggesting the plausible degradation of the azo dyes by G. candidum. The enzyme activity study showed that DyP-type peroxidase has highest activity of 900 mU ml-1 compared to that of laccase (405 mU ml-1 ) and lignin peroxidase (LiP) (324 mU ml-1 ) at optimized pH (6) and temperature (35°C). Moreover, the rate of decolourization was found to be directly proportional to the production of laccase and LiP, unlike DyP-type peroxidase. Furthermore, mineralization study demonstrated reduction in aromatic amines, showing 20% mineralization of methyl orange. CONCLUSION: Geotrichum candidum with its enzyme system is able to efficiently decolourize and mineralize the experimental azo dyes. SIGNIFICANCE AND IMPACT OF THE STUDY: The efficient decolourization and mineralization of azo dyes makes G. candidum a promising alternative in the treatment of textile effluent contaminated with azo dyes.


Assuntos
Compostos Azo/metabolismo , Corantes/metabolismo , Proteínas Fúngicas/metabolismo , Geotrichum/enzimologia , Descoloração da Água/métodos , Biodegradação Ambiental , Geotrichum/metabolismo , Lacase/metabolismo , Peroxidase/metabolismo , Peroxidases/metabolismo , Têxteis
11.
Biotechnol Lett ; 42(9): 1743-1753, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32342436

RESUMO

OBJECTIVE: Pectinase is an industrially important enzyme which is employed in an array of commercial processes; cost of production, however, impedes its application. The main objective of this study was to design a two-layered strategy for the reduction of production cost, firstly by using a yeast co-culture in an immobilized form on an agricultural waste matrix, corncob (CB), secondly by utilizing orange peels (OP) as substrate. RESULTS: Two yeast strains, Saccaromyces cerevisiae MK-157 and Geotrichum candidum AA15 were cultivated as mono-, as well as, co-culture after immobilization on CB and pectinase production was monitored. Initial experiments revealed that co-culture is beneficial to get sustainable product in subsequent 2nd and 3rd production cycles. The factors affecting pectinase production in consecutive three production cycles were studied by employing Plackett-Burman design and the significant factors were optimized through Box-Behnken design. Under optimized conditions, 17.89 IU mL-1 of pectinase was obtained. Scanning electron micrographs presented damaged immobilized yeast cells on CB after the 3rd production cycle. CONCLUSION: The pectinase production was improved substantially by using immobilized co-culture and hence the strategy was found effective at lab scale. Since, pectinase is applied in orange juice clarification, therefore, the study can be extended to move forward towards circular economy.


Assuntos
Citrus sinensis/química , Geotrichum , Poligalacturonase , Saccharomyces cerevisiae , Zea mays/química , Células Imobilizadas/citologia , Células Imobilizadas/metabolismo , Citrus sinensis/metabolismo , Técnicas de Cocultura , Proteínas Fúngicas/análise , Proteínas Fúngicas/metabolismo , Geotrichum/citologia , Geotrichum/enzimologia , Geotrichum/metabolismo , Poligalacturonase/análise , Poligalacturonase/metabolismo , Saccharomyces cerevisiae/citologia , Saccharomyces cerevisiae/enzimologia , Saccharomyces cerevisiae/metabolismo , Zea mays/metabolismo
12.
Toxins (Basel) ; 12(4)2020 03 26.
Artigo em Inglês | MEDLINE | ID: mdl-32224845

RESUMO

Fusarium sporotrichioides and F. langsethiae are present in barley crops. Their toxic metabolites, mainly T-2 toxin, affect the quality and safety of raw material and final products such as beer. Therefore, it is crucial to reduce Fusarium spp. proliferation and T-2 toxin contamination during the brewing process. The addition of Geotrichum candidum has been previously demonstrated to reduce the proliferation of Fusarium spp. and the production of toxic metabolites, but the mechanism of action is still not known. Thus, this study focuses on the elucidation of the interaction mechanism between G. candidum and Fusarium spp. in order to improve this bioprocess. First, over a period of 168 h, the co-culture kinetics showed an almost 90% reduction in T-2 toxin concentration, starting at 24 h. Second, sequential cultures lead to a reduction in Fusarium growth and T-2 toxin concentration. Simultaneously, it was demonstrated that G. candidum produces phenyllactic acid (PLA) at the early stages of growth, which could potentially be responsible for the reduction in Fusarium growth and T-2 toxin concentration. To prove the PLA effect, F. sporotrichioides and F. langsethiae were cultivated in PLA supplemented medium. The expected results were achieved with 0.3 g/L of PLA. These promising results contribute to a better understanding of the bioprocess, allowing its optimization at an up-scaled industrial level.


Assuntos
Grão Comestível/microbiologia , Microbiologia de Alimentos , Fusarium/metabolismo , Geotrichum/metabolismo , Hordeum/microbiologia , Lactatos/metabolismo , Controle Biológico de Vetores , Toxina T-2/metabolismo , Cerveja/microbiologia , Regulação para Baixo , Fermentação , Fusarium/crescimento & desenvolvimento , Cinética
13.
Appl Biochem Biotechnol ; 191(4): 1580-1593, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32185613

RESUMO

In previous studies of ionic liquid (IL) tolerance of numerous species of ascomycetous yeasts, two strains of Wickerhamomyces ciferrii and Galactomyces candidus had unusually high tolerance in media containing up to 5% (w/v) of the 1-ethyl-3-methylimidazolium acetate ([C2C1Im][OAc]). The study aimed at investigating whether additional strains of these species, and additional species in the Dipodascaceae family, also possess IL tolerance, and to compare sensitivity to the acetate and chloride versions of the ionic liquid. Fifty five yeast strains in the family Dipodascaceae, which encompasses genera Galactomyces, Geotrichum, and Dipodascus, and seven yeast strains of species Wickerhamomyces ciferrii were tested for ability to grow in laboratory medium containing no IL, 242 mM [C2C1Im][OAc], or 242 mM [C2C1Im]Cl, and in IL-pretreated switchgrass hydrolysate. Many yeasts exhibited tolerance of one or both ILs, with higher tolerance of the chloride anion than of the acetate anion. Different strains of the same species exhibited varying degrees of IL tolerance. Galactomyces candidus, UCDFSTs 52-260, and 50-64, had exceptionally robust growth in [C2C1Im][OAc], and also grew well in the switchgrass hydrolysate. Identification of IL tolerant and IL resistant yeast strains will facilitate studies of the mechanism of IL tolerance, which could include superior efflux, metabolism or exclusion.


Assuntos
Geotrichum/metabolismo , Líquidos Iônicos/química , Saccharomycetales/metabolismo , Algoritmos , Biocombustíveis , Meios de Cultura , Imidazóis , Microbiologia Industrial , Lignina/química , Filogenia , Hidrolisados de Proteína/química , RNA Ribossômico/metabolismo , Leveduras/metabolismo
14.
Int J Food Microbiol ; 319: 108503, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-31923767

RESUMO

Thirty nine strains of Galactomyces geotrichum molds were isolated from a traditional fried cottage cheese and production of polyunsaturated fatty acids (PUFA) was assessed. Among them eleven strains produced an extracellular lipids enriched in n-6 and n-3 PUFA. The extracellular lipids produced by G. geotrichum strain 38 contained the highest amounts of total PUFA (24.3%), with the highest contribution of n-3 fatty acids (17.9%), where α-linolenic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acids were the main contributors. To obtain maximal production of PUFA, composition of the medium consisted of 10 g/L rapeseed oil, 5 g/L yeast extract, 0.05 g/L K2HPO4, 0.17 g/L MgSO4, 0.015 g/L MnSO4, 0.015 g/L ZnSO4, 0.05 g/L FeSO4, and 10 mg/L vitamin B12. The optimal growth conditions at 30 °C involve: aeration at 1.5 vvm (volume of air per volume of broth per minute) at pH 6.5. The cheese produced under described conditions contained higher amount of n-3 PUFA (0.25 mg/g cheese) in comparison to control (0.01 mg/g). α-Linolenic acid predominated among n-3 fatty acids. Galactomyces geotrichum is a natural microflora of dairy products, and could be used to enrich food/cheese in deficient omega-3 lipids.


Assuntos
Queijo/microbiologia , Ácidos Graxos Ômega-3/biossíntese , Geotrichum/metabolismo , Animais , Ácidos Graxos Ômega-6/biossíntese , Geotrichum/classificação , Geotrichum/isolamento & purificação
15.
Curr Microbiol ; 77(5): 738-745, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31915987

RESUMO

This study investigated the enzymatic saccharification of alkaline-pretreated sugarcane bagasse (PSB) and the bioconversion of simple sugars from hydrolysates to ethanol and other bioproducts by the yeast Galactomyces geotrichum. The effects of percentage of dry substrate (3 and 10% w/v) and time of hydrolysis (24 and 72 h) in the content of released sugars were evaluated. The concentrations of monosaccharides and total reducing sugars (TRS) were calculated by high-performance liquid chromatography (HPLC) and by 3.5-dinitrosalicylic acid (DNS) method, respectively. The highest concentrations of TRS, glucose and xylose (73.96, 31.78 and 10.85 g/L, respectively) were obtained after the saccharification of 10% of PSB with Cellic CTec3 multi-enzyme cocktail (10 FPU/g cellulose) during 72 h (hydrolysate IV). G. geotrichum UFVJM-R150 fermented both glucose and xylose from the hydrolysates. The most efficient ethanol production was obtained after the fermentation of hydrolysate IV (9.99 g/L of ethanol, volumetric productivity-QP of 0.42 g/L.h and yield of ethanol as a function of the substrate-YP/S of 0.27 gethanol/gsugar). Besides ethanol, G. geotrichum was also able to produce other high-value chemicals such as isoamyl alcohol and galacturonic acid. This is the first report of the potential of the yeast G. geotrichum to fermentate sugarcane bagasse hydrolysates with the production of important bioproducts to further use by biorefineries.


Assuntos
Celulose/metabolismo , Etanol/metabolismo , Geotrichum/metabolismo , Saccharum/metabolismo , Reatores Biológicos , Geotrichum/enzimologia , Glucose/metabolismo , Hidrólise , Xilose/metabolismo
16.
J Food Biochem ; 43(3): e12745, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-31353560

RESUMO

Sour rot is a leading disease of citrus fruit caused by the postharvest pathogen Geotrichum citri-aurantii. It has been reported that essential oils can be used as substitutes for synthetic fungicides to control the pathogen. In this study, changes in metabolites and antifungal effects of G. citri-aurantii treated with peppermint oil (PO) were investigated. The inhibition rate of the mycelial growth increased as the PO concentration increased, and 6 µl PO/disk resulted in a radial growth inhibition of 79.2%. The electrical conductivity of G. citri-aurantii treated with PO increased compared to the control. By comparing the metabolic profiles of treated and untreated G. citri-aurantii cells, a total of 53 distinct metabolites 9 were up-regulated and 44 were down-regulated were found, including 16 lipid metabolites, 6 carbohydrate metabolites, 2 amino acid metabolites, 5 alcohols, 2 glycoside metabolites, and 3 ketone metabolites, etc, and these metabolites are involved in 25 major metabolic pathways. PRACTICAL APPLICATIONS: Chemical fungicides can effectively control G. citri-aurantii during fruit postharvest period. However, synthetic chemical fungicides have gradually led to buildup of resistance of fungil, which seriously causes the frequent of food-borne diseases. PO extracted from natural plants can be used as natural additive in many foods due to their antioxidant, antibacterial, and antifungal properties. Therefore, PO can be considered as a promising bacteriostatic agent for the defense of G. citri-aurantii during fruit postharvest period.


Assuntos
Proteínas Fúngicas/genética , Fungicidas Industriais/farmacologia , Geotrichum/química , Geotrichum/efeitos dos fármacos , Óleos Vegetais/farmacologia , Cromatografia Líquida de Alta Pressão , Citrus/microbiologia , Proteínas Fúngicas/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Regulação Fúngica da Expressão Gênica/efeitos dos fármacos , Geotrichum/genética , Geotrichum/metabolismo , Mentha piperita , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle
17.
J Appl Microbiol ; 127(4): 1148-1156, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31278818

RESUMO

AIMS: This study investigated the inhibitory effect of glutaraldehyde (GA) on sour rot in citrus fruit and the underlying antifungal mechanism on mycelial growth of the causative pathogen Geotrichum citri-aurantii. METHODS AND RESULTS: Glutaraldehyde exhibited a strong inhibitory effect on G. citri-aurantii, with a minimum inhibitory and fungicidal concentration (MFC) of 1·00 µl ml-1 . In addition, in vivo application of GA (1 × MFC and 5 × MFC) reduced the disease incidence of sour rot in citrus fruit by 60 and 80% respectively. Scanning electron microscopy results revealed that the morphology of G. citri-aurantii mycelia was greatly altered by GA treatment. Propidium iodide and Calcofluor White Staining revealed that the membrane permeability, rather than the cell wall integrity, of G. citri-aurantii mycelia was severely disrupted after the addition of GA. Massive accumulation of malonaldehyde and reactive oxygen species as well as an increase in lipoxygenase activity were observed. CONCLUSION: These results indicate that GA may inhibit the mycelia growth of G. citri-aurantii through a membrane damage mechanism induced by membrane peroxidation. SIGNIFICANCE AND IMPACT OF THE STUDY: Glutaraldehyde is expected to be a novel fungicide for controlling sour rot in citrus fruit.


Assuntos
Fungicidas Industriais/farmacologia , Geotrichum/efeitos dos fármacos , Glutaral/farmacologia , Citrus/microbiologia , Geotrichum/química , Geotrichum/metabolismo , Doenças das Plantas/microbiologia
18.
Nutrients ; 11(2)2019 Feb 23.
Artigo em Inglês | MEDLINE | ID: mdl-30813404

RESUMO

Fried cottage cheese is a dairy product, popular in some parts of Poland. Proteomic analysis of a culture of the mold Galactomyces geotrichum 38 isolated from fried cottage cheese was performed using UHPLC/MS. From the proteins identified, we selected those involved in the biosynthesis of bioactive compounds and those useful in industry. In the G. geotrichum 38 culture, the production quantities of vitamin B2 (224 µg/L), ergosterol (54.63 mg/kg), and trehalose (0.91 g/L) were determined by HPLC. The identified proteins were also used to prepare a hypothetical fatty acid biosynthesis pathway, and the percentage of individual sphingolipids in the culture was determined. Sphingolipids are also bioactive compounds. During culturing of G. geotrichum 38, the percentage of three sphingolipids increased. The last step of the research was to prepare a model of fried cottage cheese. The mold G. geotrichum 38, used in the process of ripening fried cottage cheese, synthesized vitamin B2 and erogsterol, which influenced the nutritional value of the product.


Assuntos
Queijo/microbiologia , Microbiologia de Alimentos , Regulação Fúngica da Expressão Gênica/fisiologia , Geotrichum/metabolismo , Culinária , Ergosterol/biossíntese , Proteínas Fúngicas , Humanos , Proteômica , Riboflavina/biossíntese , Esfingolipídeos/biossíntese , Trealose/biossíntese
19.
FEMS Yeast Res ; 19(1)2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30295727

RESUMO

Geotrichum candidum is a fungus-like yeast widely used as a starter culture for cheese ripening for its proteolytic and lipolytic activities and its contribution to the cheese flavours. The sequenced strain G. candidum CLIB 918 was isolated from cheese Pont-L'Evêque. This strain's ability to produce volatile compounds was compared to the ability of a known strong sulphur compound producer G. candidum strain (Gc203). The aminotransferase-coding genes BAT2 and ARO8 were identified to be involved in methionine catabolism. The production of volatile compounds indicated that the sequenced strain was a moderate producer compared to the strong producer strain. The major volatile compounds were produced from sulphur amino acid, branched-chain amino acid and fatty acid metabolisms. Metabolite content of the cells showed that the ability of the strain to produce volatile compounds was inversely proportional to its ability to store amino acids inside the cells. Reduced glutathione, hypotaurine and taurine intracellular concentrations and volatile fatty aldehyde production indicated the role of oxidative stress sensitivity in flavour production. The increase in expression of several genes in a Reblochon-type cheese at the end of ripening confirmed that oxygen and iron were key factors regulating cheese flavour production.


Assuntos
Aminoácidos/metabolismo , Aromatizantes/metabolismo , Regulação Fúngica da Expressão Gênica , Geotrichum/genética , Geotrichum/metabolismo , Estresse Oxidativo , Compostos Orgânicos Voláteis/metabolismo , Queijo/microbiologia , Geotrichum/isolamento & purificação , Redes e Vias Metabólicas/genética , Sequenciamento Completo do Genoma
20.
Molecules ; 23(9)2018 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-30150533

RESUMO

Marine-derived fungus Geotrichum candidum AS 2.361 was previously reported by our group as an active strain for the enantioselective reduction of ketones. Although some other Geotrichum strains were also found from the terrestrial sources, information on their stability and reusability is scarce. Herein, the stabilities-in terms of pH tolerance, thermostability, and storage stability, and reusability-of G. candidum AS 2.361 were described for the asymmetric reduction of a series of aromatic ketones. Two differently immobilized cells (agar immobilization and calcium alginate immobilization) as well as free cells were prepared. For three substrates (1-(3-bromophenyl) ethan-1-one (1b), 1-(2-chlorophenyl) ethan-1-one (1d), and acetophenone (1g)) immobilized cells on agar showed a great improvement in the bioreduction activities compared to the free cells, increasing yields up to 97% with ee values of 99%. Cells immobilized on agar/calcium alginate could maintain more than 90% of the original activities within the assayed pH ranges of 3.5⁻11, while free cells were highly sensitive to alkaline and acidic conditions. Concerning thermostability, immobilized cells on agar kept 99% of their original activities after incubation at 60 °C for 1 h, while almost no activity was detected for the free cells under the same condition. Immobilized cells were stable at 4 °C for 80 days without any activity loss, while free cells started to decrease the activity after storage at 4 °C for six days. The immobilized cells retained almost 99% activity after four reuse cycles, while free cells lost almost all the activities at on the third cycle.


Assuntos
Geotrichum/metabolismo , Cetonas/metabolismo , Geotrichum/ultraestrutura , Concentração de Íons de Hidrogênio , Cetonas/química , Viabilidade Microbiana , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura
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