This study aimed at isolating and characterizing of microorganisms able to use linamarin as sole carbon source. Thirty one microbial strains were isolated from manipueira, a liquid effluent of cassava processing factories. Among these strains, Bacillus licheniformis (isolate 2_2) and Rhodotorulla glutinis (isolate L1) were able to degrade 71% and 95% of added linamarin, respectively, within 7 days, showing high biodegradation activity and great potential for detoxification of cassava processing wastewaters.

O presente trabalho teve por objetivo analisar resíduos do farelo de mandioca resultantes de processos de hidrólise enzimática para obtenção de etanol; visando o aproveitamento destes como fonte de fibras dietéticas. Foram realizados quatro ensaios enzimáticos utilizando as enzimas amilolíticas, <FONT FACE="Symbol">a</font>-amilase e amiloglucosidase, complementadas ou não com celulase e/ou pectinase. Os resíduos foram caracterizados quanto à composição centesimal, pH, acidez, perfil de açúcares e quanto às fibras (FDA, FDN, celulose, hemicelulose, lignina, açúcares neutros). Realizou-se também a análise microscópica dos resíduos. Pelos resultados obtidos na caracterização dos resíduos calculou-se a energia metabolizável aparente (EM). Observou-se que independente do ensaio enzimático todos os resíduos podem ser usados como fonte de fibras insolúveis. Os resíduos resultantes dos ensaios com pectinase apresentaram uma proporção aproximada de 1:1:1 de amido, fibras e açúcares, sendo a glicose o açúcar majoritário, e com energia metabolizável aparente de cerca de 2,6 kcal/g. Já os resíduos, onde não se utilizou a pectinase a proporção foi de 2:1:1 aproximadamente e a energia 3,1 kcal/g. A análise microscópica dos resíduos mostrou a presença de amido não hidrolisado preso às células em todos os ensaios enzimáticos sendo que, nos resíduos dos ensaios com pectinase a quantidade observada foi bem inferior aos demais. Uma possível alternativa para diminuir o valor calórico dos resíduos seria a lavagem com água após a prensagem para extração do hidrolisado para fermentação.

The research had as propose to evaluate the residues of the enzymatic hydrolysis process of the ethanol production from cassava fibrous waste by dietetic fibers. Four hydrolysis process were carried out using the amylases, <FONT FACE="Symbol">a</font>-amylase and amyloglucosidase, with or without pectinase and/or cellulase. Proximate percent composition, pH, acidity, sugars and components of the fiber fraction (ADF, NDF, cellulose, hemicellulose, lignin and neutral sugars) was estimated. Microscopic analysis was made and the metabolic energy also was calculated. The results showed that all residues may be used as insoluble high-fiber product. The residues of the treatment with pectinase by complementary enzyme had a proximate proportion of the 1:1:1 starch, fibers and total sugars, and the glucose was the main sugar. The metabolic energy was 2.6 kcal/g. In the residues without pectinase the proportion was 2:1:1 and the metabolic energy was 3.1 kcal/g. Microscopic analysis showed that would have starch granules inside the unbroken cells and in the process with pectinase less granules were observed. An alternative for caloric value reduction would be the washing of the residue with water after the pressing process.

A farinha de mandioca e o fubá de milho foram avaliados como matérias-primas alternativas na obtenção de uma bebida fermento-destilada, visando gerar informações úteis à aplicação industrial. Os substratos foram caracterizados e comparou-se a eficiência da mosturação, o perfil de açúcares no mosto, bem como as curvas de fermentação dos substratos. Os resultados demonstraram que o conteúdo de amido foi de 78,1 % para o fubá de milho e 92,7 % para a farinha de mandioca. Quanto ao rendimento da mosturação foi de 57, 4 % para o milho e 66,4 % para a mandioca, sendo que o perfil de açúcares no mosto demonstrou que 95 % dos açúcares presentes no mosto de mandioca foi glicose e o restante pequenas porcentagens de dextrinas e maltose. Já o perfil do mosto de milho apresentou cerca de 85 % de glicose , 10 % de dextrinas e cerca de 4 % de maltose. Para o processo fermentativo, observou -se que o consumo de açúcares no mosto de mandioca foi mais rápido que no mosto de milho.

Cassava and corn flours were evaluated as alternative raw-materials for production of a fermented and distilled drink. The objective of this work was to generate information for technological application. Both flours were characterized and starch hydrolysis efficiency, sugar profile and fermentation pattern were compared. The results obtained showed that starch content of corn flour was 78.1% and for cassava flour 92.7%. Starch hydrolysis yield was 57.4% for corn and 66.4% for cassava and the sugar profiles in the hydrolysates showed that 95% of total sugar present in cassava hydrolysate was glucose and the remaining fraction was represented by dextrins and maltose. For corn hydrolysate 85% of total sugar was glucose, 10% dextrins and around 4% maltose. The fermentative process was evaluated by measuring the velocity of sugar consumption which for cassava hydrolysate was higher than for corn hydrolysate.

Cassava is a widely grown root crop which accumulates two cyanogenic glucosides, linamarin and lotaustralin. Linamarin accounts for more than 80% of the cassava cyanogenic glucosides. It is a ß-glucoside of acetone cyanohydrin and ethyl-methyl-ketone-cyanohydrin. Linamarin ß-linkage can only be broken under high pressure, high temperature and use of mineral acids, while its enzymatic break occurs easily. Linamarase, an endogenous cassava enzyme, can break this ß-linkage. The enzymatic reaction occurs under optimum conditions at 25ºC, at pH 5.5 to 6.0. Linamarin is present in all parts of the cassava plant, being more concentrated on the root and leaves. If the enzyme and substrate are joined, a good detoxification can occur. All the cassava plant species are known to contain cyanide. Toxicity caused by free cyanide (CN¯) has already been reported, while toxicity caused by glucoside has not. The lethal dose of CN¯ is 1 mg/kg of live weight; hence, cassava root classification into toxic and non-toxic depending on the amount of cyanide in the root. Should the cyanide content be high enough to exceed such a dose, the root is regarded as toxic. Values from 15 to 400 ppm (mg CN¯/kg of fresh weight) of hydrocyanic acid in cassava roots have been mentioned in the literature. However, more frequent values in the interval 30 to 150 ppm have been observed. Processed cassava food consumed in Brazil is safe in regard to cyanide toxicity.