Sweet sorghum: broth clarification with enzymatic treatment increases the quality of the fermentation wort for ethanol production

Sweet sorghum is currently being evaluated throughout the world as a raw material for biofuel production because its stem juices are rich in sugars that can be directly fermented to ethanol. In this work, the fermentative efficiency of three sweet sorghum genotypes was evaluated, aiming at ethanol production, harvested in two seasons, clean and whole stems, and the treatment of the juice and broth with amylolytic enzymes in order to use the present starch to increase the production of ethanol. The experiment was carried out in the 2013/2014 harvest, in the municipality of Jaboticabal, São Paulo, Brasil, located at 21°14'05''S and 48°17'09''W. The experimental design was completely randomized, with sub-subdivided plots and four replications. The primary treatments were the sweet sorghum genotypes (CV147, CV198, and BRS508), the secondary treatments, the type of harvest (whole stems and clean stems); the tertiary the two sampling times (102 and 116 days after sowing - d.a.s) and the quaternary the application of enzymes. In the fermentation process, the yeast PE-2 was used, at the end, the wine was recovered and characterized. Fermentation efficiency and liters of ethanol per ton of sorghum were calculated. The clarification of the juice with enzymatic treatment increases the quality of the fermentation broth and makes it possible to obtain wines with lower levels of RRTs and Brix. Fermentation efficiency is not affected by the genotype; however, it is influenced by the time of harvest and the technological quality of the juice. The use of amylolytic enzymes makes it possible to obtain wines with lower levels of RRTS and Brix. The best period of industrialization was at 102 d.a.s., and the processing of whole stalks resulted in less ethanol production.

Utilization of residue from cassava starch processing for production of fermentable sugar by enzymatic hydrolysis

Abstract The aim of this study was to characterize and perform enzymatic hydrolysis of cassava peeling residue (peel and inner peel), mainly composed of peels and small pieces. Residue was sanitized, dried at 55 °C for 24 hours and ground. The obtained flour showed pH of 4.85; 72.53 g 100 g-1 moisture; 5.18 mL 1M NaOH 100 g-1 acidity; 60.68 g 100 g-1 starch; 1.08 g 100 g-1 reducing sugar; 1.63 g 100g-1 ash; 0.86 g 100 g-1 lipid and 3.97 g 100 g-1 protein. Enzymatic hydrolysis was carried out by means of rotational central composite design, analyzing the effects of concentrations of α-amylase enzyme (10 to 50 U g starch-1), and the amyloglucosidase enzyme (80 to 400 U g starch-1) on variable responses: percent conversion of starch into reducing sugars (RSC) and soluble solid content (SS). Highest values of RSC (110%) and SS (12 °Brix) were observed when using the maximum concentration of amyloglucosidase and throughout the concentration range of α-amylase. Enzymatic hydrolysis of cassava peel is feasible and allows the use of hydrolysate in fermentation processes for the production of various products, such as alcoholic drinks, vinegar, among others.

Properties of Amyloglucosidase in the Digestive Tract of Periplaneta americana L. (Blattodea: Blattidae).

Aim: Partial purification and characterization of amyloglucosidase from an insect were carried out to determine the physicochemical properties of the enzyme. Study Design: It was designed to dissect digestive tracts from the American cockroach, Periplaneta americana, and to investigate the properties of the gut amyloglucosidase with a view to predicting possible industrial and pest control applications. Place and Duration of Study: The study was carried out in the Insect Physiology Laboratory of the Department of Crop Production and Protection and Department of Biochemistry, Obafemi Awolowo University, Ile-Ife, Nigeria between June and October, 2013. Methodology: Newly emerged cockroaches were dissected in ice-cold phosphate buffer and digestive tracts were collected to prepare the crude enzyme extract. Standard bioassays were constituted to purify and characterize amyloglucosidase. Results: The purification had a 71.6% yield and a specific activity of 2.53 U/mg protein. On soluble starch, the enzyme exhibited optimum activity at pH 4.0 with a Michaelis constant (Km) of 1.67 mg/ml and a maximum velocity (Vmax) of 10mg/ml/min. Amyloglucosidase activity was enhanced by Mn2+ but it was slightly inhibited by Sn2+, Mg2+ and Ni2+, while Zn2+ caused a 50% inhibition. Optimum temperature for the partially purified enzyme was 40°C and it lost about 90% of its original activity when incubated beyond 20 min at 60°C. Conclusion: Obtained results suggested that starch degradation using amyloglucosidase from P. americana could be done around pH 4 and at temperature around 40°C. This work appears to give the first report on physicochemical properties of amyloglucosidase in insects. Further studies would be needed to determine the possibility of using molecular techniques in inducing amyloglucosidase- Zn2+ complex in P. americana and to find a probable source of thermophilic amyloglucosidase which would be of importance in an industrial context.

Adsorption of amyloglucosidase from Aspergillus niger NRRL 3122 using ion exchange resin

Amyloglucosidase enzyme was produced by Aspergillus niger NRRL 3122 from solid-state fermentation, using deffated rice bran as substrate. The effects of process parameters (pH, temperature) in the equilibrium partition coefficient for the system amyloglucosidase - resin DEAE-cellulose were investigated, aiming at obtaining the optimum conditions for a subsequent purification process. The highest partition coefficients were obtained using 0.025M Tris-HCl buffer, pH 8.0 and 25ºC. The conditions that supplied the highest partition coefficient were specified, the isotherm that better described the amyloglucosidase process of adsorption obtained. It was observed that the adsorption could be well described by Langmuir equation and the values of Qm and Kd estimated at 133.0 U mL-1 and 15.4 U mL-1, respectively. From the adjustment of the kinetic curves using the fourth-order Runge-Kutta algorithm, the adsorption (k1) and desorption (k2) constants were obtained through optimization by the least square procedure, and the values calculated were 2.4x10-3 mL U-1 min-1 for k1 and 0.037 min-1 for k2 .

A enzima amiloglicosidase foi produzida por Aspergillus niger NRRL 3122 através de fermentação em estado sólido, tendo como substrato farelo de arroz desengordurado. Os efeitos dos parâmetros de processo (pH e temperatura) no coeficiente de partição no equilíbrio, para o sistema amiloglicosidase - resina DEAE-celulose foram investigados, com o objetivo de se obter as melhores condições para um posterior processo de purificação. Os maiores coeficientes de partição foram obtidos usando tampão Tris-HCl 0,025M pH 8,0 e 25°C. Determinadas as condições que forneceram o maior coeficiente de partição obteve-se a isoterma que melhor descrevia o processo de adsorção de amiloglicosidase. Foi verificado que adsorção pode ser bem descrita pela equação de Langmuir e os valores de Qm e Kd foram estimados em 133,0 U mL-1 e 15,4 U mL-1 respectivamente. A partir do ajuste das curvas cinéticas utilizando o método de Runge-Kutta de quarta ordem, obteve-se as constantes de adsorção (k1) e dessorção (k2) através da otimização pelo método dos mínimos quadrados, os valores encontrados foram 2,4x10-3 mL U-1 min-1 para k1 e 0,037 min-1 para k2.

Simultaneous amyloglucosidase and exo-polygalacturonase production by Aspergillus niger using solid-state fermentation

Amyloglucosidase (AMG) and exo-polygalacturonase (exo-PG) were simultaneously produced by two different strains of Aspergillus niger in solid-state fermentation (SSF) using defatted rice-bran as substrate. The effect of Aspergillus niger strain (t0005/007-2 and/or CCT 3312), inoculum type (spore suspension or fermented bran) and addition of inducers (pectin and/or starch) to the culture media was studied using a 3² x 2¹ factorial experimental design. The production of AMG and exo-PG was significantly affected by fungal strain and inoculum type but inducers had no effect. The maximum yields obtained were 1310 U/g dm for AMG using a spore suspension of A. niger CCT 3312 and 50.2 U/g dm for exo-PG production, using A. niger t0005/007-2 and fermented bran as inoculum. The yields obtained represented acceptable values in comparison with data available in the literature and indicated that defatted rice-bran was a good nutrient source.

As enzimas amiloglicosidase (AMG) e exo-poligalacturonase (exo-PG) foram produzidas simultaneamente por duas cepas de Aspergillus niger, através de fermentação em estado sólido usando farelo de arroz desengordurado como substrato. Foram avaliados os efeitos da cepa de Aspergillus niger, tipo de inóculo e adição de indutores no meio de cultura, utilizando-se um planejamento experimental fracionário 3² x 2¹. O máximo rendimento obtido foi 1310 U/g ms para a produção de AMG e 50,2 U/g ms para a exo-PG. Comparando-se estes resultados com dados da literatura pode-se dizer que os rendimentos obtidos foram aceitáveis e indicam que o farelo de arroz desengordurado é uma boa fonte de nutrientes. A produção de AMG e exo-PG foi significativamente afetada pelas variáveis cepa de A. niger e tipo de inóculo, enquanto a variável indutor não apresentou influência significativa na produção destas enzimas.