Amylase from Bacillus sp. Produced by Solid State Fermentation Using Cassava Bagasse as Starch Source

Abstract Amylases are enzymes involved in starch hydrolysis, generating the most diverse products, such as maltose, glucose and dextrins. This work aimed the study of the production of amylolytic enzymes via solid-state fermentation (SSF) using "crueira", an essentially starchy cassava residue, as substrate-support and Bacillus sp. as microorganism. For the implementation of the experimental part, a Central Composite Design (CCD) with three variables (initial moisture, pH and temperature) was made. Each test was examined at 24, 48 and 72 hours by the method of starch dextrinizing activity. The optimum production conditions were 60% initial moisture, pH 6 and 37 °C. The maximum yield was 437.76 U/g in 72 hours of fermentation. The optimum temperature of enzyme performance was 65 °C. The pH optimum range was 4 to 6. The Co2 +, Ca2 + and K+ ions positively influenced the activity of enzymes and the Fe2+ ion had no effect on enzymatic activity. On the other hand, the ions Hg2+, Zn2+, Cu2+, Mn2+ and Mg2+ adversely influenced enzymatic activity. Therefore, producing amylases from Bacillus sp. and using crueira as a substrate is possible.

Saccharomyces cerevisiae populations and other yeasts associated with indigenous beers (chicha) of Ecuador

ABSTRACT Chicha, a type of beer made mainly with maize or cassava, is a traditional fermented beverage of the Andean region. There have only been a few studies on yeasts associated with chicha fermentation, and the species diversity occurring during the production of this beverage is not known. The objective of this study was to determine the biodiversity of yeasts in chicha, and to characterize the Saccharomyces cerevisiae populations associated with the production of chicha de jora, seven-grain chicha, chicha de yuca, and chicha de morocho in Ecuador. The molecular diversity of S. cerevisiae populations was determined by restriction polymorphism mitochondrial profiles. The beverages were characterized based on their physicochemical parameters. Twenty-six species were identified, and the most prevalent species were S. cerevisiae and Torulaspora delbrueckii. Other yeast species were isolated at low frequencies. Among 121 isolates of S. cerevisiae, 68 different mtDNA molecular profiles were identified. These results showed that chichas are fermented by a high number of different strains of S. cerevisiae. Some other species provided a minor contribution to the fermentation process. The chicha presented generally similar physicochemical parameters to those observed for other traditional fermented beverages, and can be considered as an acid fermented beverage.

Selection of starter cultures for the production of sour cassava starch in a pilot-scale fermentation process

ABSTRACT Sour cassava starch (Polvilho azedo) is obtained from a spontaneous fermentation conducted by microorganisms from raw materials and fermentation tanks. This product is traditionally used in the baking industry for the manufacture of biscuits and Brazilian cheese breads. However, the end of fermentation is evaluated empirically, and the process occurs without standardization, which results in products of inconsistent quality. Predominant microbiota from a cassava flour manufacturer was isolated in order to select starter cultures for the production of sour cassava starch in a pilot-scale fermentation process. Lactic acid bacteria and yeasts were isolated, enumerated and grouped by Restriction Fragment Length Polymorphism, and PCR fingerprinting, respectively. One isolate of each molecular profile was identified by sequencing of the rRNA gene. LAB were prevalent throughout the entire process. Lactobacillus brevis (21.5%), which produced the highest values of acidity, and Lactobacillus plantarum (13.9%) were among the most frequent species. Pichia scutulata (52.2%) was the prevalent yeast and showed amylolytic activity. The aforementioned species were tested as single and mixed starter cultures in a pilot-scale fermentation process for 28 days. L. plantarum exhibited better performance as a starter culture, which suggests its potential for the production of sour cassava starch.

Efecto del consumo de casabe sobre la absorción y retención aparente de proteínas en un modelo experimental con ratas / Effect of casabe bread consumption on apparent absorption and retention of proteins in a rat experimental model

El principal producto derivado de la yuca en Venezuela es el casabe, valorado por su contenido calórico y de Fibra Dietética (FD). Objetivo: determinar el efecto del consumo de diferentes variedades de casabe sobre la absorción y retención aparente de proteínas en un modelo experimental con ratas. Métodos: se utilizaron 20 ratas machos adultas, cepa Sprague Dawley®, las cuales fueron divididas en 4 grupos: un control sin fibra y tres grupos experimentales en los que se sustituyó el almidón de maíz por una variedad de casabe, identificados por su procedencia como: "Casabe Miranda", "Casabe Sucre" y "Casabe Amazonas". Resultados: el contenido de FD total y su fracción soluble fueron significativamente mayores en las variedades de casabe Amazonas y Sucre (p<0,05). La inclusión de casabe a las dietas produjo un aumento en el peso de las heces así como en su contenido de nitrógeno (p<0,05), sin presentar diferencias significativas en la excreción de nitrógeno urinaria. La absorción de proteínas y la retención aparente de nitrógeno disminuyeron significativamente (p<0,05) hasta el día 14 del período experimental. Sin embargo, se pudo apreciar que al final del ensayo (día 21) la retención aparente de nitrógeno no mostró diferencia entre los controles y los grupos experimentales. Conclusiones: la inclusión de casabe a las dietas no produjo una reducción en la utilización de proteínas como para afectar el crecimiento de los animales. Se plantea la necesidad de seguir realizando estudios en esta área ya que la literatura es muy escasa(AU)

The main product derived from cassava in Venezuela is cassava bread, valued for its caloric content and Dietary Fiber (DF). Objective: to determine the effect of the consumption of different varieties cassava bread on the absorption and retention of proteins in a rat experimental model. Methods: Twenty male adult rats, Sprague Dawley ® strain, were divided into four groups: a control without fiber and three experimental groups in which corn starch was substituted for a variety of cassava bread, identified by their origin as: "Cassava bread Miranda", "Cassava bread Sucre" and "Cassava bread Amazonas". Results: The total DF content and soluble fraction were significantly higher in the varieties of cassava breads varieties Amazonas and Sucre (p <0.05). The inclusion of cassava bread in diets produced an increase in stool weight as well as in nitrogen content (p <0.05), without presenting significant differences in the excretion of urinary nitrogen. Protein absorption and apparent nitrogen retention decreased significantly (p <0.05) until day 14 of the experimental period. However, it could be seen that at the end of the trial (day 21) the apparent nitrogen retention showed no difference between the controls and the experimental groups. Conclusions: the inclusion of cassava bread in the diets did not produce a reduction in the use of proteins to affect the growth of the animals. The need to continue conducting studies in this area is considered, since the literature is very scarce(AU)

A new alkalophilic isolate of Bacillus as a producer of cyclodextrin glycosyltransferase using cassava flour

Abstract Cyclodextrin glycosyltransferase (CGTase) catalyzes the conversion of starch into non-reducing cyclic sugars, cyclodextrins, which have several industrial applications. This study aimed to establish optimal culture conditions for β-CGTase production by Bacillus sp. SM-02, isolated from soil of cassava industries waste water lake. The optimization was performed by Central Composite Design (CCD) 2, using cassava flour and corn steep liquor as substrates. The maximum production of 1087.9 U mL−1 was obtained with 25.0 g L−1 of cassava flour and 3.5 g L−1 of corn steep after 72 h by submerged fermentation. The enzyme showed optimum activity at pH 5.0 and temperature 55 °C, and maintained thermal stability at 55 °C for 3 h. The enzymatic activity was stimulated in the presence of Mg+2, Ca+2, EDTA, K+, Ba+2 and Na+ and inhibited in the presence of Hg+2, Cu+2, Fe+2 and Zn+2. The results showed that Bacillus sp. SM-02 have good potential for β-CGTase production.

Bagaço de mandioca na ensilagem do capim-elefante: qualidade das silagens e digestibilidade dos nutrientes / Cassava bagasse in elephant grass ensilage: quality of the silage and digestibility of the nutrients

Utilizaram-se 16 novilhas ¾ Holandês-Zebu com idade média de 15 meses e peso médio inicial de 144kg, para avaliar o efeito da adição de diferentes níveis (5; 10; 15 e 20 por cento) de bagaço de mandioca na ensilagem do capim-elefante (Pennisetum purpureum, Schum) sobre a qualidade e a digestibilidade dos nutrientes da dieta. Os tratamentos consistiram de quatro dietas contendo, como volumoso, silagem de capim-elefante com quatro diferentes níveis de bagaço de mandioca, mais concentrado balanceado, com quatro repetições por tratamento. Avaliou-se a qualidade das silagens, os consumos de nutrientes das dietas e as digestibilidades dos nutrientes das silagens e das dietas totais. O bagaço de mandioca elevou o teor de matéria seca (MS) da silagem, preservando-a com o pH que variou de 3,85 a 4,07 e a relação N-NH3/NT de 6,2 a 7,85. Os consumos médios diários de MS e proteína bruta (PB) não diferiram entre os tratamentos (P>0,05). Os consumos médios de fibra em detergente neutro (FDN) e fibra em detergente ácido (FDA) apresentaram comportamento linear decrescente (P<0,05) com o aumento dos níveis de bagaço de mandioca. Não foi detectada diferença entre os tratamentos (P>0,05) na digestibilidade da MS (DMS), da FDN (DFDN) e da FDA (DFDA) das silagens. Os nutrientes digestíveis totais (NDT) das silagens foram semelhantes em todos os tratamentos. A digestibilidade da PB (DPB), do extrato etéreo (DEE) e dos carboidratos não-fibrosos (DCNF) das silagens decresceu linearmente (P<0,05) com o aumento do nível do bagaço de mandioca nas silagens. Constatou-se que não houve diferença (P>0,05) na DMS, DPB, DFDN, DFDA, DEE, DCNF e NDT entre as dietas experimentais. O nível de adição de 5 por cento de bagaço de mandioca à silagem de capim-elefante é satisfatório para sua preservação, propiciando boa digestibilidade.

Sixteen ¾ Holstein-Zebu heifers aging 15 month-old averaging 144kg were used to evaluate the effect of the additions of different levels of cassava bagasse (5; 10; 15 and 20 percent) to elephant grass (Pennisetum purpureum, Schum) ensilage on the diet quality and nutrients digestibility. The treatments consisted of four diets containing, as roughage, elephant grass silage with four different levels of cassava bagasse plus balanced concentrate, with four repetitions per treatment. Silages quality, diet nutrients intake and nutrients digestibility of the silages and total diets were evaluated. Cassava bagasse increased the dry matter (DM) content, of the silages preserving them with a pH varying from 3.85 to 4.07 and N-NH3/NT ratio from 6.2 to 7.85. Daily dry matter and crude protein (CP) mean intakes did not differ among the treatments (P>0.05). Neutral detergent fiber (NDF) and acid detergent fiber (ADF) mean intakes showed a decreasing linear behavior (P<0.05) with the increase of cassava bagasse levels. There was no detected difference among the treatments (P>0.05) for DM (DMD), NDF (NDFD) and ADF digestibility (ADFD). The total digestible nutrients (TDN) of the silages were similar in all the treatments. The CP (CPD), ether extract (EED) and non-fiber carbohydrates digestibility (NFCD) of the silages decreased linearly (P<0.05) with the increase of cassava bagasse levels. There was no difference (P>0.05) in DMD, CPD, NDFD, ADFD, EED, NFCD and TDN among the experimental diets. The 5 percent cassava bagasse addition to its elephant grass silage was satisfactory to preservation resulting in good digestibility of the elephant grass silage.

Bemnisia tabaci feeding induces pathogenesis-related proteins in cassava (Manihot esculenta Crantz).

Cassava (Manihot esculenta Cranzts) plants fed upon by whitefly Bemisia tabaci showed increased levels of pathogenesis-related (PR) proteins, such as beta-1, 3-glucanase, peroxidase and chitinase activities, as compared to uninfested plants. The enzymes increased in specific activities from 2 to 7 fold and protein content in leaf extracts decreased in whitefly-infested plants, compared to uninfested plants. Among the three PR proteins, B. tabaci feeding induced significantly higher beta-1, 3-glucanase activities, when compared with other two PR proteins. Study also discussed the possible application of PR proteins in whitefly control program.

Desempenho de novilhas leiteiras alimentadas com silagem de capim-elefante com adição de diferentes níveis de bagaço de mandioca / Performance of dairy heifers fed on elephantgrass silage added with different levels of cassava bagasse

Avaliou-se o efeito da adição de diferentes níveis (5; 10; 15 e 20 por cento) de bagaço de mandioca na ensilagem do capim-elefante (Pennisetum purpureum, Schum) sobre o desempenho de novilhas leiteiras. Utilizaram-se 16 novilhas ¾ Holandês × Zebu, com idade média de 15 meses e peso vivo inicial de 144kg, com quatro repetições por tratamento. O experimento constou de 14 dias de adaptação, quando as novilhas receberam apenas silagem, e 56 dias de período experimental. Realizaram-se pesagens e tomadas as medidas da altura de cernelha e da circunferência torácica, após jejum de 16 horas, no início do experimento e no 28° e 56° dias. Os consumos médios diários de matéria seca (MS) e proteína bruta não diferiram entre tratamentos (P>0,05). Os consumos médios de fibra em detergente neutro e fibra em detergente ácido apresentaram comportamento linear decrescente (P<0,05). O desempenho foi verificado por meio das médias do peso vivo inicial, do peso vivo final, do ganho de peso médio diário, do aumento de perímetro torácico, do aumento de altura de cernelha e da conversão alimentar da MS. Não se observou influência dos tratamentos (P>0,05) sobre as características estudadas.

Nutrient enrichment of cassava peels using a mixed culture of Saccharomyces cerevisae and Lactobacillus spp solid media fermentation techniques

Cassava pulp was fermented with pure strains of Saccharomyces cerevisae and two bacteria namely Lactobacillus delbruckii and Lactobacillus coryneformis for 3 days. The squeezed liquid from the fermented pulp was used to ferment cassava peels for 7 days. Analysis of the dried fermented peels revealed that there was a significant (P < 0.05) increase in the protein content of the cassava peels fermented with squeezed liquid from the inoculated cassava pulp (21.5%) when compared with the unfermented cassava peel (8.2%). Moreover, the treatment equally brought about a significant (P < 0.05) decrease in the cyanide (6.2 mg/kg) and phytate content (789.7 mg/100g) when compared with the unfermented cassava peels, which had 44.6 mg/kg cyanide and 1043.6 mg/100g phytate. The fermented cassava peels could be a good protein source in livestock feeds.

Linamarin- the toxic compound of cassava

Cassava is a widely grown root crop which accumulates two cyanogenic glucosides, linamarin and lotaustralin. Linamarin accounts for more than 80 per cent of the cassava cyanogenic glucosides. It is a beta-glucoside of acetone cyanohydrin and ethyl-methyl-ketone-cyanohydrin. Linamarin beta-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 beta-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- 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.