Gustavo Adolfo Saavedra Pinto

Hydrolytic enzyme production in solid-state fermentation by Aspergillus niger 3T5B8

Abstract A mixture containing polygalacturonase, cellulase, xylanase and protease enzymes was produced using Aspergillus niger 3T5B8 on different agroindustrial residues by solid-state fermentation and tested for vegetable oil extraction. The enzymic activities were evaluated using second-order empirical models from experimental data as a function of fermentation time and cellobiose concentration in the fermentation medium. The use of wheat bran as substrate without cellobiose addition and 42 h of fermentation were the most favourable conditions for producing the mixture of hydrolytic enzymes (polygalacturonase 30.75 U/ml, xylanase 30.62 U/ml, protease 5.27 U/ml). Another favourable condition was obtained when mango peel was used as substrate in the presence of 0.2% cellobiose and 24 h of fermentation (FPCAse 3.5 U/ml, xylanase 20.33 U/ml). Enzymic formulations with suitable polygalacturonase and FPCAse activities were favourable to extract oil from the pulp of tropical fruits and oleaginous seeds.

Biosorption of Heavy Metals by Powder of Green Coconut Shell

Abstract Alternative processing methods are being considered more seriously, sorption and/or complexation of dissolved metals based on the chemical activity of biomass, known as biosorption, is the base of the new technology for metal removal and recovery. Different types of biomass (dead and alive) like bacteria, yeast, bark, fungi, agricultural by‐products, coconut shell, marine algae, peat, moss and aquatic mosses have been investigated for biosorption of heavy metals ions. Biosorption of each of the metal ions by coconut shell powder was investigated in this study. The biosorption capacities of coconut shell for cadmium, chromium, and arsenic were studied at different particle sizes (0.044–0.297 mm), initial metal concentration (20– 1000 mg/L), and solution pH values 2–9 in batch mode, the experimental data obtained for each metal were evaluated and fitted using adsorption models. Also, analyses were made of biomass by SEM‐EDS before and after the biosorption to confirm the presence of metal ions species.

Selection of tannase-producing Aspergillus niger strains

The aim of this work was to select strains of Aspergillus niger for tannase production. Growth of colonies in plates with tannic acid-containing medium indicated their ability to synthesize tannase. Tannase activity was also measured in solid-state fermentation. A. niger 11T25A5 was the best tannase producer (67.5 U.g-1/72 hours of fermentation).

Enzymatic synthesis of prebiotic oligosaccharides.

Prebiotic oligosaccharides are nondigestible carbohydrates that can be obtained by enzymatic synthesis. Glucosyltransferases can be used to produce these carbohydrate through an acceptor reaction synthesis. When maltose is the acceptor a trisaccharide composed of one maltose unit and one glucose unit linked by an α-1,6-glycosidic bond (panose) is obtained as the primer product of the dextransucrase acceptor reaction. In this work, panose enzymatic synthesis was evaluated by a central composite experimental design in which maltose and sucrose concentration were varied in a wide range of maltose/sucrose ratios in a batch reactor system. A partially purified enzyme was used in order to reduce the process costs, because enzyme purification is one of the most expensive steps in enzymatic synthesis. Even using high maltose/sucrose ratios, dextran and higher-oligosaccharide formation were not avoided. The results showed that intermediate concentrations of sucrose and high maltose concentration resulted in high panose productivity with low dextran and higher-oligosaccharide productivity.

Immobilization of Candida antarctica Lipase B by Covalent Attachment to Green Coconut Fiber

The objective of this study was to covalently immobilize Candida antarctica type B lipase (CALB) onto silanized green coconut fibers. Variables known to control the number of bonds between enzyme and support were evaluated including contact time, pH, and final reduction with sodium borohydride. Optimal conditions for lipase immobilization were found to be 2 h incubation at both pH 7.0 and 10.0. Thermal stability studies at 60°C showed that the immobilized lipase prepared at pH 10.0 (CALB-10) was 363-fold more stable than the soluble enzyme and 5.4-fold more stable than the biocatalyst prepared at pH 7.0 (CALB-7). CALB-7 was found to have higher specific activity and better stability when stored at 5°C. When sodium borohydride was used as reducing agent on CALB-10 there were no improvement in storage stability and at 60°C stability was reduced for both CALB-7 and CALB-10.

Tannase Production by Solid State Fermentation of Cashew Apple Bagasse

The ability of Aspergillus oryzae for the production of tannase by solid state fermentation was investigated using cashew apple bagasse (CAB) as substrate. The effect of initial water content was studied and maximum enzyme production was obtained when 60 mL of water was added to 100.0 g of CAB. The fungal strain was able to grow on CAB without any supplementation but a low enzyme activity was obtained, 0.576 U/g of dry substrate (gds). Optimization of process parameters such as supplementation with tannic acid, phosphorous, and different organic and inorganic nitrogen sources was studied. The addition of tannic acid affected the enzyme production and maximum tannase activity (2.40 U/gds) was obtained with 2.5% (w/w) supplementation. Supplementation with ammonium nitrate, peptone, and yeast extract exerted no influence on tannase production. Ammonium sulphate improved the enzyme production in 3.75-fold compared with control. Based on the experimental results, CAB is a promising substrate for solid state fermentation, enabling A. oryzae growth and the production of tannase, with a maximum activity of 3.42 U/gds and enzyme productivity of 128.5×10−3 U · gds−1 · h−1.

Production of Biosurfactant by Pseudomonas aeruginosa Grown on Cashew Apple Juice

In this work, the ability of biosurfactant production by Pseudomonas aeruginosa in batch cultivation using cashew apple juice (CAJ) and mineral media was evaluated. P. aeruginosa was cultivated in CAJ, which was supplemented with peptone (5.0 g/L) and nutritive broth. All fermentation assays were performed in Erlenmeyer flasks containing 300 mL, incubated at 30°C and 150 rpm. Cell growth (biomass and cell density), pH, and superficial tension were monitored vs time. Surface tension was reduced by 10.58 and 41% when P. aeruginosa was cultivated in nutrient broth and CAJ supplemented with peptone, respectively. These results indicated that CAJ is an adequate medium for growth and biosurfactant production. Best results of biosurfactant production were obtained when CAJ was supplemented with peptone.

Produção de ácido lático e dextrana utilizando suco de caju como substrato

The main aim of the present work was to study the use of agriculture excess as substrates for dextran and lactic acid production. The fermentations were carried out with the microorganism Leuconostoc mesenteroides B512F in a medium containing cashew apple juice and sucrose. The concentrations of reducing sugar and sucrose were varied according to factorial planning. At the end of the fermentation the dextran, the lactic acid and biomass produced were quantified.The results were analyzed by the surface response analysis methodology. According to the results increasing the sugar level favors dextran and lactic acid production. The use of cashew apple juice as an alternative substrate for dextran and lactic acid production presented technical viability.

Aplicação da metodologia de superfície de resposta no estudo da produção e extração da poligalacturonase

The aim of this work was to verify the effects of initial medium moisture content (U), addition of ammonium sulphate (N) and of potassium phosphate (P) in the production of the polygalacturonase through the solid-state fermentation, using cashew apple husk as substrate and Aspergillus niger CCT0916 as transformation agent. We also studied the best extraction conditions of the produced enzyme. The best condition of production was with U of 40%, 1% of N and 0% of P being reached an activity of the poligalacturonase of 10.1 U/g. The best extraction condition is an agitation system with a time of 100 min and a solvent-fermented medium volume ratio of 5 mL/g.

Avaliação da produção de ácido lático por Leuconostoc mesenteroides B512F em xarope de caju

The production of lactic acid by fermentation accounts for more than 50% of the world production. To meet the demand, efforts to lower the costs have been the objective of several studies. This work aimed to study the lactic acid production in cashew apple (Anacardium orcidentale) syrup. The microorganism used was the Leuconostoc mesenteroides B512F. In the experimental investigation, the ideal concentrations of yeast extract and initial sugar were determined. A second experimental investigation was carried out with cashew apple syrup by adding yeast extract and phosphate and by diluting the syrup according to the initial sugar concentrations to optimize the medium culture. A kinetic study was carried out with the optimized substrate obtained. The results showed that the studied strains can produce lactic acid in satisfactory concentrations provided the natural syrup substrate contains only yeast extract and phosphate.