Tamires Carvalho dos Santos

Optimization of productions of cellulolytic enzymes by Aspergillus niger using residue of mango a substrate

The present paper analyses the effects of water activity (0.88, 0.94 and 0.97) and of fermentation time (24, 48, 72, 96 and 120 hours) on the kinetic activity of enzymes cellulolytic, produced during the solid state fermentation of waste from the improvement of mango, with the aid of fungus species Aspergillus niger. Solid state fermentation was carried out at 35°C inside a bacteriological incubator. The statistical results indicated that the best activity for enzyme CMCase was 7.26U g-1 after 74.51 hours of fermentation, whereas for enzyme FPase was 2.55U g-1 after 98.52 hours, both presenting best results in approximately 0.928 of water activity. Pareto charts have showed that fermentation time has greater effect over the activity of enzyme CMCase, while the water activity variable has greater effect over enzyme FPase activity. During fermentation the fungus synthesized the enzymes without the need of inductors other than mango residue and water.

Application of Response Surface Methodology for Producing Cellulolytic Enzymes by Solid-state Fermentation from the Puple Mombin (Spondias purpurea L.) Residue

This study aimed at demonstrating the effects of fermentation time (24, 48, 72, 96, and 120 h) and water activity (0.943, 0.970, and 0.985) on the production of cellulolytic enzymes by solid-state fermentation of purple mombin (Spondias purpurea L.) residue using Aspergillus niger. The fermentation was carried out at 35°C and the enzyme production was measured as endoglucanase and total cellulose activities. The optimum condition for endoglucanase was water activity 0.974 and 93.8 h of fermentation, reaching a production of 3.21 U/g of residue; whereas for total cellulase it was 0.958 and 79.4 h achieving 12.1 U/g of residue. Fermentation time had a greater effect on the endoglucanase activity, while water activity had a more significant influence on the total cellulase activity. Endoglucanase had optimum activity at temperature of 50°C and pH 5.0. Although cellulase total optimum activity was also at pH 5.0, the maximum activity was at 60°C.

Prickly palm cactus husk as a raw material for production of ligninolytic enzymes by Aspergillus niger

Prickly palm cactus husk was used as a solid-state fermentation support-substrate for production of the ligninolytic enzymes laccase, peroxide manganese, and lignin peroxidase by Aspergillus niger. Effects of water activity, temperature, and fermentation time on enzymatic production were evaluated using a central composite rotatable design. Response surface methodology revealed that maximum enzyme production was achieved at 73.38 h of fermentation, a water activity of 0.87 Aw, at 28.74°C for laccase, at 65.33 h, 0.89 Aw, and 28.96°C for lignin peroxidase, and at 70.44 h, 0.91 Aw, and 28.84°C for manganese peroxidase. Optimized enzyme production was 9,023.67 UI/L for laccase, 2,234.75 UI/L for lignin peroxidase, and 8,534.81 UI/L for manganese peroxidase. Thermostability and pH stability were observed for all enzymes. Enzymatic deactivation kinetic experiments indicated that enzymes remained active after freezing of crude extracts.

Statistical Optimization of Culture Conditions and Characterization for Ligninolytic Enzymes Produced from Rhizopus Sp. Using Prickly Palm Cactus Husk

Dry prickly palm cactus (Nopalea cochenillifera) husk was investigated as a substrate for Rhizopus sp. cultivation in the solid state, aiming at the production of laccase (Lac), lignin peroxidase (LiP), and manganese peroxidase (MnP). The optimization of fermentation was evaluated by an experimental design and it was obtained, for each enzyme, maximum productivities (U g−1 h−1) of: 0.085 ± 0.02 (MnP), 0.066 ± 0.001 (LiP), and 0.023 ± 2.3.10−4 (Lac), at the conditions of 10 g of substrate, 72 h of fermentation, aw = 0.865, and 30°C. The enzymes thermal and pH stabilities were evaluated and it was observed better results at temperatures no higher than 60°C and pH of 5.0; in addition, the storage of these enzymes was better at − 25°C than at 4°C. Since the prickly palm cactus is an agricultural substrate and specially because of its low cost, it is important to propose different applications for it as, for example, an alternative substrate for biotechnological processes.