Infección fúngica invasiva por Saprochaete capitata en un niño con aplasia medular / Invasive fungal infection by Saprochaete capitata in a child with bone marrow aplasia

RESUMEN Saprochaete capitata es una causa rara de infección fúngica invasiva en pacientes inmunocomprometidos con alta mortalidad y resistencia antifúngica. Presentamos el caso de un niño de cinco años con diagnóstico de aplasia medular, sometido a trasplante de progenitores hematopoyéticos (TPH), que cursó con neutropenia febril persistente, dolor abdominal intenso, aparición de lesiones maculopapulares en piel y deterioro de la función renal. Se identificó la presencia de S. capitata, en hemocultivos transcatéter venoso central. Esta infección fúngica invasiva resulta ser rara, pero emergente y potencialmente mortal, en pacientes con neutropenia febril persistente y uso prolongado de dispositivos invasivos intravasculares como catéter venoso central.

ABSTRACT Saprochaete capitata is a rare cause of invasive fungal infection in immunocompromised patients with high mortality and antifungal resistance. We present the case of a 5-year-old boy with bone marrow aplasia, who underwent hematopoietic stem cell transplantation (HSCT) and presented persistent febrile neutropenia, abdominal pain, appearance of maculopapular lesions on the skin, and impaired renal function. The presence of S. capitata was identified by blood culture from a central venous catheter. This invasive fungal infection is rare but emergent and life-threatening, especially in immunocompromised patients with persistent febrile neutropenia and prolonged use of invasive devices such as central venous catheters.

Geotrichum spp: An overlooked and fatal etiologic agent in immunocompromised patients. A case series from a referral center in Mexico.

Geotrichum spp. is an emergent pathogen. We aimed to describe Geotrichum spp. invasive fungal infections (IFI) in patients from Mexico. We reviewed cases with Geotrichum spp. isolated in clinical samples, from 2001 to 2019. Descriptive analysis was used for clinical data. Twenty patients with proven/probable Geotrichum spp. IFI were analyzed. The median age was 43; 55% were males. Hematologic malignancy was found in 60% (12/20); 75% (15/20) received systemic immunosuppressors. The most common presentation was lower respiratory tract infection. In-hospital mortality was 45% (9/20). Geotrichum spp. should be acknowledged as a pathogen causing atypical pneumonia in immunocompromised Latin American patients. LAY SUMMARY: Geotrichum spp. causes invasive infection in immunocompromised hosts. We describe a case series of 20 patients from Mexico City. Hematologic malignancy was the most common comorbidity. Clinical presentation was mainly lower respiratory tract infection. Mortality was high despite antifungal therapy.

Calidad microbiológica del aire en seis áreas de la microestación biológica- Zoocriadero de la Universidad Nacional Agraria de la Selva ­ Tingo María ­ Perú / Microbiological quality of air in six areas of the biological micro station - Zoocriadero of the Universidad Nacional Agraria de la Selva - Tingo Maria ­ Peru

El presente trabajo de investigación tiene como objetivo evaluar la calidad microbiológica del aire en seis áreas de la Microestación Biológica-Zoocriadero de la Universidad Nacional Agraria de la Selva-Tingo María-Perú; procediéndose de la siguiente manera: Se seleccionaron seis áreas de muestreo (A1: Boletería, A2: Caseta gallito de las rocas, A3: Zona de las tortugas, A4: Caseta del otorongo, A5: Caseta de los monos y A6: Cocina), de los cuales para la determinación de los parámetros físicos (PAS, temperatura, humedad relativa, precipitación y rosa de viento) se obtuvo información de la estación meteorológica de la UNAS y de lecturas directas en campo, para la determinación de las PAS se realizó por el método pasivo obteniéndose la mayor concentración de PAS en el área 1 "Boletería" (12.61 t/km2/mes, 11.08 t/km2/mes y 8.4 t/km2/mes) y la más baja en el área 5 "caseta de los monos" (2.80 t/km2/mes, 2.80 t/km2/mes y 3.2 t/km2/mes); para el análisis microbiológico se realizó por el método de borboteo en líquidos, identificándose 27 géneros entre bacterias y hongos, siendo las bacterias más frecuentes Bacillus sp., Staphylococcus sp., Enterobacter agglomerans, Klebsiella pneumoniae, Enterobacter hafniae y algunas bacterias patógenas para el hombre como Streptococcus sp., Clostridium perfringens, Bacillus anthracis. Los hongos de mayor frecuencia son Penicillium sp., Aspergillius sp., Geotrichum sp., algunos hongos patógenos identificados: Microsporum sp., Epirophyton sp. Por otro lado, para la percepción del público como trabajadores se aplicó encuestas, donde indicaron que la calidad microbiológica del aire en la Microestación Biológica-Zoocriadero es regular(AU)

The objective of this research paper is to assess the microbiological quality of the air in six areas of the Biologial Micro-station and animal breeding farm of the Peruvian Univeristy "Universidad Nacional Agraria de la Selva in Tingo María, Perú", proceeding as follows: Six sampling areas were selected (A1: Ticket Office, A2: Cock-of-the-Rock hut, A3: Turtle area, A4: Otorongo hut, A5: Monkey hut, A6: Kitchen), of wich for the determination of the phisical parameters (SBP, temperature, relative humidity, precipitation and wind rose) information was obtained from the UNAS meteorological station and direct readings in the field. For the determination of SBP was performed by the passive method obtaining the high concentration of SBP in area 1 "Ticket Office" (12.61 t/km2/month, 11.08 t/km2/month and 8.4 t/km2/month) and the lowest in area 5 "monkey house" (2.80 t/km2/month, 2.80 t/km2/month and 3.2 t/km2/month); microbiological analysis was performed by the liquid bubbling method, identifying 27 genera incluiding bacteria and fungi, with the most frequent bacteria being Bacillus sp., Staphylococcus sp., Enterobacter agglomerans, Klebsiella pneumoniae, Enterobacter hafniae and some bacteria pathogenic for humans such as Streptococcus sp., Clostridium perfringens and Bacillus anthracis. The most frequent fungi are Penicillium sp., Aspergillius sp. and Geotrichum sp.; some pathogenic fungi identified: Microsporum sp., Epirophyton sp. On the other hand,regarding the perception of the public and workers, surveys were applied, wich indicated that the microbiologial quality of the air in the Biological Micro-station and animal breeding farm is regular(AU)

Purification of a killer toxin from Aureobasidium pullulans for the biocontrol of phytopathogens.

The objectives of the present study were to purify and assess the killer toxin effect produced by Aureobasidium pullulans under casual agents of green mold (Penicillum digitatum) and sour rot (Geotrichum citri-aurantii). Initially, different methods of protein precipitation were tested. The proteolytic activity and the presence of proteins acting on cell wall receptors, ß-1,3-glucanase and chitinase were determined, and toxin purification was conducted by Sephadex G-75 gel exclusion chromatography and cellulose chromatography (medium fibers). Subsequently, purification was confirmed by polyacrylamide gel electrophoresis, and the detection of killer activity was performed in solid YEPD-methylene blue buffered with citrate-phosphate (0.1 M, pH 4.6). Toxin identification was performed by liquid chromatography-mass spectrometry. The results showed that the best protein precipitation method was 2:1 ethanol (vol/vol ethanol/supernatant). It was possible to observe the presence of enzymes with proteolytic activity, including ß-1,3-glucanase and chitinase. During the purification process, it was verified that the killer toxin produced by the yeast has a low-molecular-weight protein belonging to the ubiquitin family, which presents killer activity against P. digitatum and G. citri-aurantii.

Curative activity of postharvest GRAS salt treatments to control citrus sour rot caused by Geotrichum citri-aurantii.

The effectiveness of the "generally recognized as safe" (GRAS) salts potassium sorbate (PS), sodium benzoate (SB), sodium ethylparaben (SEP) and sodium methylparaben (SMP) to control sour rot, caused by Geotrichum citri-aurantii, was assessed by dipping economically important citrus species and cultivars in aqueous solutions for 30, 60 or 150 s at 20 °C, followed by examination after 8 d of storage at 28 °C. Curative activity was determined because the fruit were inoculated 24 h prior to treatment. Dipping fruit for 60 s in SMP (200 mM), SEP (200 mM) or SB (3% w/v) were very effective and reduced sour rot incidence and severity by up to 90%. Their effectiveness was similar or superior to that of the conventional fungicide propiconazole (PCZ). In contrast, PS (200 mM) did not control sour rot on 'Oronules' or 'Ortanique' mandarins, but it reduced sour rot incidence on 'Barnfield' oranges by 50% compared to inoculated, water-treated control fruit. Sour rot was better controlled on oranges than on mandarins. Furthermore, heating the solutions to 50 °C enhanced their effectiveness, while post-treatment rinsing of the fruit with tap water reduced their effectiveness. Dipping 'Valencia Late' oranges in SB (3% w/v) or SMP (200 mM) for 60 s followed by long storage for up to 8 weeks at 5 °C and 90% RH, reduced sour rot incidence from 55% among water-treated control fruit to 2 to 6%, and matched the effectiveness of PCZ. No fruit in any test were visibly harmed. Both SB and SMP salts could be potential alternatives to conventional fungicides, such as PCZ or guazatine, for the integrated postharvest management of citrus sour rot.

Biocatalytic production of Ɛ-caprolactone using Geotrichum candidum cells immobilized on functionalized silica.

Immobilization of the Geotrichum candidum (CCT 1205) cell with functionalized silica creates promising biocatalysts for production of ɛ-caprolactone. The results obtained by immobilization of the whole cell on SiO2-NH2 and SiO2-SH supports indicate that the presence of reactive functional groups on the support may promote effective chemical bonds with the cell walls resulting the decreased dehydrogenases enzyme activity (5% yield in less than 2h) and consequently, increased Baeyer-Villiger monooxygenases enzyme activity with redacting of 25% of time reaction when is used SiO2-NH2 as support and 50% through use of SiO2-SH as support relative to free cells when cyclohexanone is used as a substrate. The catalysts SiO2-NH2-Geotrichum candidum and SiO2-SH-Geotrichum candidum were recycling and reused in the ɛ-caprolactone synthesis from cyclohexanone, and the biocatalysts promoted a quantitative conversion up to the eighth reaction cycle. KEY POINTS: • Immobilized microorganism is more efficient than free cell in the caprolactone synthesis. • The reaction times for amino and thiol groups in support were 3 h and 2 h, respectively. • These catalysts showed higher ɛ-caprolactone conversion at higher concentrations.

Exploring the interaction between citrus flavonoids and phytopathogenic fungi through enzymatic activities.

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.

Production of volatile compounds by yeasts using hydrolysed grape seed oil obtained by immobilized lipases in continuous packed-bed reactors.

Lipases CAL-B, TLL, and RML were used in the synthesis of free fatty acids of grape seed oil as heterogeneous substrate. The best enzyme was used to optimize the reaction variables temperature, enzyme content, and molar ratio of water:oil in batch reactions using experimental planning. The ideal conditions to produce free fatty acids using pure RML were 45 °C, 12:1 substrate molar ratio, and 15% enzyme, resulting in 66% of oil hydrolysis and a productivity of 0.54 mol L-1 min-1 in 4 h of reaction at 180 rpm. Repeated batches of reaction were performed testing the operational stability of RML, results showing that this enzyme could be used for at least 20 cycles keeping more than 80% of its initial activity, suggesting its potential use in industrial processes. The synthesis of free fatty acids was then evaluated in continuous reactions using packed-bed reactor (PBR). The highest productivity in the continuous process was 6.85 mol L-1 min-1, using only RML, showing an operational stability higher than 80% of its initial conversion capacity after 11 days of operation, at a flow rate of 0.13 mL min-1 at 45 °C. We evaluated the use of this hydrolyzed oil as substrate for lactone bioproduction using Galactomyces geotrichum UFMG-CM-Y3276, G. geotrichum UFMG-CM-Y3558, and Geotrichum klebahnii UFMG-CM-Y3014 screened for their oil-hydrolysis ability. Volatile compounds were qualitatively identified in GC-MS as γ-octalactone and γ-nonalactone.

Ethanol Production and Other Bioproducts by Galactomyces geotrichum from Sugarcane Bagasse Hydrolysate.

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.

Biological Control of Citrus Postharvest Phytopathogens.

Citrus are vulnerable to the postharvest decay caused by Penicillium digitatum, Penicillium italicum, and Geotrichum citri-aurantii, which are responsible for the green mold, blue mold, and sour rot post-harvest disease, respectively. The widespread economic losses in citriculture caused by these phytopathogens are minimized with the use of synthetic fungicides such as imazalil, thiabendazole, pyrimethanil, and fludioxonil, which are mainly employed as control agents and may have harmful effects on human health and environment. To date, numerous non-chemical postharvest treatments have been investigated for the control of these pathogens. Several studies demonstrated that biological control using microbial antagonists and natural products can be effective in controlling postharvest diseases in citrus, as well as the most used commercial fungicides. Therefore, microbial agents represent a considerably safer and low toxicity alternative to synthetic fungicides. In the present review, these biological control strategies as alternative to the chemical fungicides are summarized here and new challenges regarding the development of shelf-stable formulated biocontrol products are also discussed.

Optimization of free fatty acid production by enzymatic hydrolysis of vegetable oils using a non-commercial lipase from Geotrichum candidum.

This study aimed to optimize free fatty acid production by enzymatic hydrolysis of cottonseed, olive and palm kernel oils in stirred-tank reactors using a lipase from Geotrichum candidum (GCL-I). The effect of pH, temperature and substrate concentration on the hydrolytic activity of GCL-I using these vegetable oils was investigated. Thermal stability tests and thermodynamic studies were also performed. A complete hydrolysis of cottonseed oil was obtained after 120 min of reaction, while for olive and palm kernel maximum hydrolysis percentage was 96.4% and 60.1%, respectively. GCL-I exhibited the highest activity in the hydrolysis of vegetable oils that are rich in unsaturated-fatty acids (cottonseed and olive oils). Under optimal conditions (46.8% m/m of oil, 6.6 U/g of the reaction mixture at 40 °C), complete cottonseed oil hydrolysis was observed at 60 min of reaction performed in an emulsifier-free system with no buffer.

Biofilm production by Aureobasidium pullulans improves biocontrol against sour rot in citrus.

The biocontrol efficiency of Aureobasidium pullulans strain ACBL-77 against Geotrichum citri-aurantii, causal agent of sour rot in citrus, and their interactions were evaluated. For this, were evaluated the incorporation of nutrients in optimizing the antagonistic activity of the yeast, the competition for nutrients between microorganisms, the effect of nutrients on yeast cell and biofilm production and their correlation in the biocontrol of disease, the survival of yeast in citrus fruits and the interaction between microorganisms using scanning electron microscopy. Micronutrients (boric acid, cobalt chloride and ammonium molybdate) favoured the antagonistic action of A. pullulans. Ammonium sulfate 1% and sucrose 0.5% favoured the yeast during the competition between the microorganisms. The addition of ammonium sulfate (1%) in the yeast culture stimulated biofilm production and increased the antagonistic activity against the disease, as also allowed the better survival of yeast in wounded sites of citrus fruit. The yeast was found to be able to form biofilms on citrus, deforming the pathogen hyphae. These results showed the importance of the addition of nutrients in A. pullulans based-formulations when aiming for their use on a commercial scale. This is the first report of a positive correlation between the increase in the quantity of biofilm produced by A. pullulans, with increased antagonistic activity.

Xylitol production and furfural consumption by a wild type Geotrichum sp

Background: Xylitol is a five carbons polyol with promising medical applications. It can be obtained from chemical D-xylose reduction or by microbial fermentation of Sugarcane Bagasse Hemicellulosic Hydrolysate. For this last process, some microbial inhibitors, as furfural, constitute severe bottleneck. In this case, the use of strains able to produce xylitol simultaneously to furfural neutralization is an interesting alternative. A wild-type strain of Geotrichum sp. was detected with this ability, and its performance in xylitol production and furfural consumption was evaluated. Furthermore, were analyzed its degradation products. Results: Geotrichum sp. produced xylitol from D-xylose fermentation with a yield of 0.44 g-g-1. Furfural was fully consumed in fermentation assay and when provided in the medium until concentration of 6 g-L-1. The furfural degradation product is not an identified molecule, presenting a molecular weight of 161 g-mol-1, an uncommon feature for the microbial metabolism of this product. Conclusion: This strain presents most remarkable potential in performing furfural consumption simultaneous to xylitol production. Subsequent efforts must be employed to establish bioprocess to simultaneous detoxification and xylitol production by Geotrichum sp.

Geotrichum candidum as a possible cause of bovine abortion.

Geotrichum spp. are ubiquitous, saprotrophic fungi found in soil, organic matter, and silage, as a contaminant in food products and in the digestive tracts of mammals. The current study reports a case of Geotrichum candidum infection with dermatitis in an aborted bovine fetus with skin and lung lesions. A 6-month-old aborted male Holstein Friesian fetus displayed unusual lesions on the skin of the abdomen, thorax, and head, which was excessively thickened and wrinkled. These changes corresponded to orthokeratotic hyperkeratosis, neutrophil accumulation in the stratum corneum, a pyogranulomatous inflammatory infiltrate, and superficial dermal necrosis. Moderate suppurative multifocal pneumonia was observed. Large numbers of mononuclear cells and occasional fibrin thrombi within blood vessels were found in the lungs, brain, and cerebellum. Gridley staining revealed fungal structures within the skin lesions. The mycological exam demonstrated the growth of G. candidum, and phase contrast microscopy conducted on the abomasal fluid revealed hyphae compatible with this agent. The skin lesions observed, in association with the fungus isolated, indicated that the abortion was due to G. candidum infection of the bovine fetus.

Leveduras e Geotrichum capitatum do trato digestivo e fezes de emas (rhea americana) mantidas em cativeiro: identificação e sensibilidade antifúngica in vitro / Geotrichum capitatum and yeast digestive tract and feces of emas (rhea americana) kept in captivity: identification and sensitivity in vitro antifungal

[...] Em 36/58 dos animais foram isoladas leveduras a partir de orofaringe e em 35/58 a partir da cloaca. Um total de 117 isolados foi obtido, pertencentes aos gêneros Candida (77/117), Trichosporon (25/117) Geotrichum (11/117) e Rhodotorula (4/117). A C. parapsilosis foi a espécie mais presente (19/117), seguida por C. albicans (18/117), C. tropicalis (13/117), C. guilliermondii (12/117), G. capitatum (11/117), T. mucoides (11/117), C. krusei (10/117), C. famata (5/117), T. asteroides (5/117), R. mucilaginosa (4/117), T. asahii (3/117), T. cutaneum (3/117) e T. ovoides (3/117). Houve maior presença de C. albicans na orofaringe das emas jovens do que nos adultos (p <0,001). Enquanto o G. capitatum foi mais frequente nas amostras de cloaca de animais adultos (p<0,05); assim como foi mais presente em cloaca que em orofaringe tanto em jovens como adultos (p<0,01). Quanto às espécies de Candida não foi observada resistência à anfotericina B, mas 16 cepas foram simultaneamente resistentes aos dois derivados azólicos (11/18 C. albicans, 1/10 C. krusei, 2/19 C. parapsilosis e 2/13 C. tropicalis). Houve elevada resistência principalmente em cepas de C. albicans ao fluconazol (15/18) e ao itraconazol (13/18). Outras espécies apresentaram resistência, como: C. parapsilosis (7/19 ao fluconazol e 3/19 ao itraconazol), C. tropicalis (6/13 ao fluconazol e 5/13 ao itraconazol), C. guilliermondii (1/12 ao itraconazol) e C. krusei (2/10 ao fluconazol e 1/10 ao itraconazol). Quanto às outras leveduras e G. capitatum a maioria dos isolados foi sensível aos antifúngicos in vitro, no entanto, a resistência frente fluconazol (1) e itraconazol (2) foi detectada em T. mucoides. Por fim, 23/77 cepas Candida spp. secretaram fosfolipases. Em síntese, o trato digestivo dos animais estudados presentou heterogeneidade de espécies de Candida potencialmente patogênicas, uma vez que parte delas apresentou resistência aos derivados azólicos e secretaram fosfolipases.

[...] In 36/58 animals was isolated fungi from the oropharynx and in 35/58 from the cloaca. A total of 77 isolates were obtained, belonging to genera Candida (77/117), Trichosporon (25/117) Geotrichum (11/117) and Rhodotorula (4/117). The C. parapsilosis was the more frequent species isolated (19/117), followed by C. albicans (18/117), C tropicalis (13/117), C guilliermondii (12/117), G. capitatum (11/117), T. mucoides (11/117) C. krusei (10/117), C famata (5/117), T. asteroides (5/117), R. mucilaginosa (4/117), T. asahii (3/117), T. cutaneum (3/117) and T. ovoides (3/117). There was greater presence of C. albicans in the oropharynx of the juvenile rheas than in the adults (p<0.001), while G. capitatum was more frequent in cloacal samples from adult animals (p<0.05), as well as it was more present in cloaca than in oropharynx, both in youth as in adults (p<0.01). As Candida species, no resistance was observed to amphotericin B, but 16 strains were simultaneously resistant to the two azole derivatives (11/18 C. albicans, 1/10 C. krusei, 2/19 C. parapsilosis and 2/13 C. tropicalis). There was particularly high resistance of C. albicans strains to fluconazole (15/18) and to itraconazole (13/18). Other species showed resistance, as: C. parapsilosis (7/19 to fluconazole and 3/19 to itraconazole), C. tropicalis (6/13 to fluconazole and 5/13 to itraconazole), C. guilliermondii (1/12 to itraconazole), C. krusei (2/10 to fluconazole and 1/10 to itraconazole). As others yeasts and G. capitatum most of the isolates were susceptible to antifungals in vitro; however, resistance against fluconazole (1) and itraconazole (2) was detected in T. mucoides. Finally, 23/77 Candida spp. strains secreted phospholipases. In summary, this study indicates that digestive tract of the studied animals showed heterogeneity of potentially pathogenic Candida species, since some of them were resistant to azole derivatives and secreted phospholipases.

Imobilização de lipase em matriz polimérica para produção de bioaroma / Immobilization of lipase on polymer matrix for synthesis of flavor

Os ésteres são importantes compostos orgânicos, obtidos por síntese química ou extraídos de alguns produtos naturais utilizando-se solvente em meio adequado. ... O principal objetivo deste trabalho foi a obtenção de acetato de butila, um éster de aroma característico de abacaxi, utilizando lipase de Geotrichum candidum produzida em fermentação submersa e imobilizada em matriz polimérica de alginato de bário e gelatina reticulada com glutaraldeído. A caracterização bioquímica foi realizada tanto para a lipase na forma livre como para a lipase na forma imobilizada. O rendimento em conversão molar de substrato foi determinado por cromatografia gasosa. A enzima apresentou atividade enzimática máxima após 48 horas de fermentação de 37,7 U/mL. Os valores ótimos para pH e temperatura da enzima na forma livre e imobilizada foram pH 6,5 e 40 °C e pH 7,5 e 45 °C, respectivamente. A enzima na forma livre foi estável do pH 6,0 ao 8,0 e à temperatura de 35 a 45 °C, já na forma imobilizada, foi estável do pH 5,5 ao 8,5 e na faixa de temperatura de 30 a 55 °C. A lipase imobilizada teve seus parâmetros cinéticos determinados, e os valores obtidos para o Km e Vmax, foram 0,115 mmol e 0,718 µmol.mL-1.min-1, respectivamente. As melhores condições de síntese do bioaroma para a enzima na forma livre foram: temperatura de 30 °C, 12,5% de enzima em relação à quantidade de butanol utilizada, proporção molar do substrato 60% de acetato de vinila em um período de 24 horas. O rendimento alcançado neste caso foi de 97,2 % de conversão molar em acetato de butila. Para a enzima imobilizada as melhores condições foram: temperatura de 45 °C, 12,5% de enzima em relação à quantidade de butanol utilizada, proporção molar do substrato 60% de acetato de vinila em um período de 24 horas. O rendimento alcançado neste caso foi de 99,1%, que demonstra que lipase produzida por Geotrichum candidum na forma imobilizada apresenta excelente capacidade de sintetizar acetato de butila (bioaroma de abacaxi)

Esters are important organic compounds obtained by chemical synthesis or derived from some natural products using a solvent in appropriate medium. Studies have shown that enzymes, particularly lipases, ca be applied in the synthesis of various esters. The main objective of this study was to obtain butyl acetate, a characteristic ester aroma of pineapple, using lipase from Geotrichum candidum produced in submerged fermentation and immobilized in a barium alginate and gelatin polymer matrix crosslinked with glutaraldehyde. The biochemical characterization was performed for both free and immobilized lipases. The yield in molar conversion of substrate was determined by gas chromatography. The enzyme showed maximum enzymatic activity after 48 hours of fermentation of 37.7 U/mL. The optimum values for pH and temperature of the enzyme in free and immobilize form were pH 6.5 and 40 °C and pH 7.5 and 45 °C, respectively. The enzyme was stable in free form from pH 6.0 to 8.0 and at temperatures from 35 to 45 °C, and in the immobilized form from pH 5.5 to 8.5 and at temperatures from 30 to 55 °C. Kinetic parameters of the immobilized lipase were determined, and the values obtained for Km and Vmax were 0.115 mmol and 0.718 µmol.mL-1.min-1, respectively. The best conditions for the synthesis of flavor by enzyme in free form were: 30 °C of temperature, 12.5% of enzyme for the amount of butanol used, and molar ratio of substrate 60% of vinyl acetate in a 24 hours period. The yield achieved in this case was 97.2% of molar conversion in butyl acetate. For the immobilized enzyme the best conditions were: 45 °C of temperature, 12.5% of enzyme for the amount of butanol used, and molar ratio of substrate 60% of vinyl acetate in a 24 hours period. The yield achieved in this case was 99.1%, demonstrating that lipase produced by Geotrichum candidum in immobilized form has an excellent ability to synthesize butyl acetate (pineapple flavor)

Influência do uso de cultura adjunta nas características físico-químicas e sensoriais do queijo tipo Camembert / Effect of the addition of a supplementary culture on the physical physicalchemical and sensory characteristics of Camembert-type cheese

O presente estudo avaliou o efeito da adição do Geotrichum candidum, como cultura adjunta, na aceitação e composição do queijo tipo Camembert. O leite utilizado na fabricação dos queijos foi submetido à pasteurização e adicionado de Lactococcus lactis subsp. Lactis e Lactococcus lactis subsp. cremoris. Foram realizados quatro tratamentos: controle (T1) – sem adição de Geotrichum candidum; e T2, T3 e T4, com concentrações, respectivamente, de 0,5 U, 1 U e 1,5 U do microorganismo. Após 1, 9, 17, 25, 33 e 41 dias de fabricação, os queijos foram avaliados quanto aos parâmetros: acidez, pH, proteína, NS a pH 4,6, NS em TCA12%, umidade, e para gordura e sal no queijo com um dia de preparação. A análise de aceitação foi realizada aos 30 dias de maturação. Os queijos com e sem adição de Geotrichum candidum não diferiram (P > 0,05) nas análises físico-químicas. Os quatros tratamentos diferiram (P < 0,05) em todas as análises no decorrer do tempo de maturação. Com o aumento na concentração do Geotrichum candidum, houve aumento na média de aceitação dos provadores. A utilização do Geotrichum candidum é uma boa alternativa para as indústrias que desejam um produto com boa aceitabilidade e características semelhantes ao tradicional queijo Camembert.

Influência do uso de cultura adjunta nas características físico-químicas e sensoriais do queijo tipo Camembert / Effect of the addition of a supplementary culture on the physical-chemical and sensory characteristics of Camembert-type cheese

O presente estudo avaliou o efeito da adição do Geotrichum candidum, como cultura adjunta, na aceitação e composição do queijo tipo Camembert. O leite utilizado na fabricação dos queijos foi submetido à pasteurização e adicionado de Lactococcus lactis subsp. Lactis e Lactococcus lactis subsp. cremoris. Foram realizados quatro tratamentos: controle (T1) sem adição de Geotrichum candidum; e T2, T3 e T4, com concentrações, respectivamente, de 0,5 U, 1 U e 1,5 U do microorganismo. Após 1, 9, 17, 25, 33 e 41 dias de fabricação, os queijos foram avaliados quanto aos parâmetros: acidez, pH, proteína, NS a pH 4,6, NS em TCA 12%, umidade, e para gordura e sal no queijo com um dia de preparação. A análise de aceitação foi realizada aos 30 dias de maturação. Os queijos com e sem adição de Geotrichum candidum não diferiram (P > 0,05) nas análises físico-químicas. Os quatros tratamentos diferiram (P < 0,05) em todas as análises no decorrer do tempo de maturação. Com o aumento na concentração do Geotrichum candidum, houve aumento na média de aceitação dos provadores. A utilização do Geotrichum candidum é uma boa alternativa para as indústrias que desejam um produto com boa aceitabilidade e características semelhantes ao tradicional queijo Camembert.(AU)

This study evaluated the effect of Geotrichum candidum addition as an adjunct culture on the acceptance and composition of Camembert-type cheese. The milk used for cheese manufacturing was pasteurized and supplemented with Lactococcus lactis subsp. Lactis and Lactococcus lactis subsp. cremoris. Four treatments were performed: control (T1) without adding Geotrichum candidum; T2-T3-T4: containing microorganisms at concentrations of 0.5 U, 1 U and 1.5 U, respectively. After 1, 9, 17, 25, 33 and 41 days of manufacture, the cheese samples were analyzed on the following parameters: acidity, pH, protein, soluble nitrogen at pH 4.6, TCA 12 % soluble nitrogen, and moisture, and fat and salt contents in cheese after 1-day production. Sensory analysis was performed after 30 days of maturing. No significant difference was found in the physical-chemical analysis in cheeses produced with and without adding Geotrichum candidum (P > 0.05). However, significant differences (P < 0.05) were detected in all of the analyses throughout the maturing period. The acceptance of cheese by tasters increased with the rise of Geotrichum candidum concentration added into the cheese. The use of Geotrichum candidum is a valuable alternative for industries seeking for a product with favorable acceptability and with characteristics similar to the traditional Camembert-type cheese.(AU)

Proteinase and phospholipase activities and development at different temperatures of yeasts isolated from bovine milk.

The presence of yeasts in milk may cause physical and chemical changes limiting the durability and compromising the quality of the product. Moreover, milk and dairy products contaminated by yeasts may be a potential means of transmission of these microorganisms to man and animals causing several kinds of infections. This study aimed to determine whether different species of yeasts isolated from bovine raw milk had the ability to develop at 37°C and/or under refrigeration temperature. Proteinase and phospholipase activities resulting from these yeasts were also monitored at different temperatures. Five genera of yeasts (Aureobasidium sp., Candida spp., Geotrichum spp., Trichosporon spp. and Rhodotorula spp.) isolated from bovine raw milk samples were evaluated. All strains showed one or a combination of characteristics: growth at 37°C (99·09% of the strains), psychrotrophic behaviour (50·9%), proteinase production (16·81% of the strains at 37°C and 4·09% under refrigeration) and phospholipase production (36·36% of the isolates at 37°C and 10·9% under refrigeration), and all these factors may compromise the quality of the product. Proteinase production was similar for strains incubated at 37°C (16·81% of the isolates) and room temperature (17·27%) but there was less amount of phospholipase-producing strains at room temperature (15·45% of the isolates were positive) when compared with incubation at 37°C (36·36%). Enzymes production at 37°C by yeasts isolated from milk confirmed their pathogenic potential. The refrigeration temperature was found to be most efficient to inhibit enzymes production and consequently ensure better quality of milk. The viability of yeasts and the activity of their enzymes at different temperatures are worrying because this can compromise the quality of dairy products at all stages of production and/or storage, and represent a risk to the consumer.