The group of Gram-negative bacteria capable of oxidising ethanol to acetic acid is called acetic acid bacteria (AAB). They are widespread in nature and play an important role in the production of food and beverages, such as vinegar and kombucha. The ability to oxidise ethanol to acetic acid also allows the unwanted growth of AAB in other fermented beverages, such as wine, cider, beer and functional and soft beverages, causing an undesirable sour taste. These bacteria are also used in the production of other metabolic products, for example, gluconic acid, l-sorbose and bacterial cellulose, with potential applications in the food and biomedical industries. The classification of AAB into distinct genera has undergone several modifications over the last years, based on morphological, physiological and genetic characteristics. Therefore, this review focuses on the history of taxonomy, biochemical aspects and methods of isolation, identification and quantification of AAB, mainly related to those with important biotechnological applications.
Sugar cane silage has a potential for animal feeding, but uncontrolled growth of undesirable microorganisms may cause nutritional losses and affect the animal productivity and health. The objective of this work was to evaluate the microbiological quality and chemical composition of ensiled sugar cane with and without nutritional additives after 30 days of fermentation. Yeasts, filamentous fungi and distinct groups of bacteria were enumerated by plate count methods and the chemical analyzes comprised dry matter, crude protein, fiber content, lignin, and pH. Facultative aerobic bacteria and filamentous fungi were not detected during the fermentative process in any of the treatments. The number of yeasts in five varieties of sugar cane silage without additives was about 6.55 Log CFU g -1 of silage, and with 1% ammonium sulfate and 1% urea were about 5.86 and 5.50 Log CFU g -1 of silage, respectively. The lactic acid bacteria (LAB) count without additive was about 8.62 Log CFU g -1 of silage, and with 1% ammonium sulfate and 1% urea the count was about 6.40 and 6.54 Log CFU g -1 of silage, respectively. The average percent of dry material in the three treatments was 20.76%. The addition of ammonium sulphate and urea has decreased the microbial load after 30 days but it has increased the total crude protein concentration. Additives also affected neutral detergent fiber, acid detergent fiber and lignin content in all five varieties of sugar cane silage.
Carboxymethyl-glucan (CM-G) is a soluble derivative from Saccharomyces cerevisiae (1 → 3)(1 → 6)-β-D-glucan. The protective efficiency of CM-G against DNA damage in cells from patients with advanced prostate cancer (PCa), and undergoing Androgen Deprivation Therapy (ADT), was evaluated. DNA damage scores were obtained by the comet assay, both before and after treatment with CM-G. The reduction in DNA damage, ranging from 18% to 87%, with an average of 59%, was not related to the increased number of leukocytes in peripheral blood. The results demonstrate for the first time the protective effect of CM-G against DNA damage in patients with advanced PCa. Among smokers, three presented the highest reduction in DNA damage after treatment with CM-G. There was no observable relationship between DNA damage scores before and after treatment, and age, alcoholism and radiotherapy.
Resumoβ-glucanas são polissacarídeos constituintes estruturais da parede celular de leveduras, fungos e alguns cereais, que se diferenciam pelo tipo de ligação presente entre as unidades de glicose. Uma importante fonte destes polissacarídeos é a parede celular de Saccharomyces cerevisiae, uma levedura amplamente empregada em processos industriais de fermentação. A β-glucana é considerada um modificador da resposta biológica devido ao seu potencial imunomodulador, pois ao ser reconhecida por receptores celulares específicos tem habilidade de realçar a resposta imune do hospedeiro. Outros efeitos benéficos como anticarcinogênico, antimutagênico, hipocolesterolêmico e hipoglicêmico também têm sido relacionados à β-glucana Esta revisão de literatura teve por objetivo agregar conhecimentos científicos sobre a constituição e bioatividade da β-glucana, incluindo seu reconhecimento pelo sistema imune, bem como, a obtenção a partir da parede celular de S. cerevisiae. Palavras-chave: β-glucana, Saccharomyces cerevisiae, bioatividade, imunomodulador, sistema imune Abstract β-glucans are polysaccharides that constitute the structure of the cell wall of yeast, fungi and some cereals, which differs each other by the linkages between glucose units. An important source of these polymers is the Saccharomyces cerevisiae cell wall, which is a yeast widely used in industrial processes of fermentation. The β-glucan is considered to be a modifier of biological response due to its immunomodulator potential. When it is recognized by specific cellular receptors, have the ability to enhance the host's immune response. Other beneficial effects such as anticarcinogenic, antimutagenic, hypocholesterolemic and blood sugar reduction have also been related to the β-glucan. The aim of this literature review was expand scientific knowledge about the constitution and bioactivity of β-glucan, including its recognition by the immune system, as well as its obtaining from S. cerevisiae cell wall.
These findings suggest that CM-G modulate positively the vascular function, mainly in responses NO-dependent. CM-G and βG-Sc have an anti-aggregation effect, being CM-G more selective to ADP-induced platelet aggregation.
The oyster mushroom, Pleurotus ostreatus, cultivated in solid state on sugarcane bagasse-wheat bran (5:1) medium in the presence of veratryl alcohol resulted in an increased production of the fruiting body at earlier times compared to when the fungus was grown in the absence of veratryl alcohol. The results indicate a new physiological role for veratryl alcohol in stimulating fruiting body formation. Veratryl alcohol also stimulated laccase production during the mycelial growth stage. Evidence is also presented that laccases were involved in the physiological development of the fruiting body.
RESUMO.A biomassa de levedura resultante da produção de cerveja é mátéria-prima para extração de componentes celulares, incluíndo manoproteínas. O presente trabalho avaliou a possibilidade da utilização da levedura Saccharomyces sp. descartada em cervejaria, para obtenção de extrato com manoproteínas. A extração foi conduzida segundo delineamento fatorial incompleto, Box-Behnken 3 3 , para as variáveis temperaturas (75, 85 e 95ºC), tempo de extração (5, 7 e 9h) e concentração da suspensão de parede celular (10, 15 e 20%). O etanol residual da fermentação não interfere na obtenção do extrato contendo manoproteínas. O maior índice de extração foi 4,08%, observado para temperatura de 95ºC na concentração de 10% por 7h e 15% por 9h. A validação experimental do maior índice predito resultou em 4,50% de extrato, confirmando a capacidade preditiva do modelo. A manoproteína obtida, a partir de 10% de parede celular (95ºC, 9h), apresentou 51,39% de proteínas, com 58 e 64 kDa, e 25,89% de carboidratos, distribuídos entre manose e glicose. A atividade emulsificante foi de 62,50 ± 0,88% e a estabilidade da emulsão foi de 96,00 ± 1,40%. Estes resultados evidenciam o potencial bioemulsificante do extrato e a viabilidade de utilização da levedura descartada em cervejarias para obtenção de compostos com propriedades industriais interessantes.Palavras-chave: Saccharomyces sp., bioemulsificante, levedura cervejeira. Obtainment and characterization of mannoproteins from brewer's yeast cell wallABSTRACT. The biomass of yeast after beer production is a raw-material for cell components extraction, including mannoproteins. The present study evaluated the using viability of spent brewer's yeast Saccharomyces sp. for obtainment of extract containing mannoprotein. The extraction was conducted by Box-Behnken 3 3 incomplete design, for the variables temperature (75, 85 and 95ºC), time of extraction (5, 7 and 9h) and concentration of cell wall in suspension (10, 15 and 20%). The residual ethanol of fermentation doesn't have interference in the obtaining of extract containing mannoproteins. The highest rate of extraction was 4.08%, obtained at 95ºC, with 10% cell wall by 7h and with 15% of cell wall during 9h. The experimental validation for obtaining of the maximum predicted resulted in 4.50% of extract, confirming the model predictable capacity. The extract containing mannoprotein obtained from 10% of cell wall (95ºC, 9h) had 51.39% of proteins, with 58 and 64 kDa, and 25.89% of carbohydrates, distributed in mannose and glucose. The emulsification activity was 62.50 ± 0.88% and the emulsion stability was 96.00 ± 1.4%. These results evidence the bioemulsifier potential of the extract and the viability of using spent yeast from brewery for obtainment of compounds with industrial interesting properties.
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