Effect of Metal Ions, Chemical Agents and Organic Compounds on Lignocellulolytic Enzymes Activities

Lignocellulolytic enzymes have been extensively studied due to their potential for industrial applications such as food, textile, pharmaceutical, paper, and, more recently, energy. The influence of metal ions, chemical agents, and organic compounds on these enzyme activities are addressed in this chapter, based on data available in the scientific literature

Studies on the application of Myceliophthora thermophila JCP1-4 cellulases cocktail on sugarcane bagasse pretreated by different methods

The hydrolysis step for sugar production in biorefineries is crucial for the sequential processes involved and cellulases cocktails behave differently according to the pretreatment employed. In this study, the application of the cellulases cocktail produced by the fungus Myceliophthora thermophila JCP1-4 was studied on the saccharification of sugarcane bagasse pretreated by ozonolysis and thermic ferric nitrate (TFN), and the results were compared with commercial enzymes (Novozymes Celluclast 1.5L, Novozym 188). The fungal cellulases cocktail hold an activity of FPU:β-glucosidase of 1:4(U/mL); time, temperature, FPU by g of cellulose load and percentage of dry matter (DM) were studied. The analysis of central composite design of TFN pretreated showed that fungal cellulases works better in DM values of 3–3.5% (4.5% for commercial), temperatures higher than 50 °C (<45 °C for commercial) and 15FPU for both; commercial enzymes yielded 7.78 g/L of reducing sugars and the fungal enzymes 5.42 g/L. With the ozone pretreated, the fungal enzymes presented a higher thermostability with faster kinects, being able to produce 5.56 g/L of reducing sugars (60 °C, 8 h), against 5.20 g/L for commercial enzymes (50 °C, 24 h), (10FPU, 3%DM for both). The FPU derivate analysis revels better yields with 7.5FPU, and the increase of DM to 7.5% resulted 13.28 g/L of reducing sugars

Influence of Different Substrates on the Production of a Mutant Thermostable Glucoamylase in Submerged Fermentation

Three mutations, Ser54 -> Pro, Thr314 -> Ala, and His415 -> Tyr, were identified in Aspergillus awamori glucoamylase gene expressed by Saccharomyces cerevisiae. The mutant glucoamylase (GA) was substantially more thermostable than a wild-type GA at 70 A degrees C, with a 3.0 KJ mol(-1) increase in the free energy of thermo-inactivation. The effect of starch from different botanical sources on the production of this GA was measured in liquid fermentation using commercial soluble starch, cassava, potato, and corn as the carbon source. The best substrate for GA production was the potato starch showing an enzymatic activity of 6.6 U/mL. The commercial soluble starch was also a good substrate for the enzyme production with 6.3 U/mL, followed by cassava starch and corn starch with 5.9 and 3.0 U/mL, respectively. These results showed a significant difference on GA production related to the carbon source employed. The mutant GA was purified by acarbose-Sepharose affinity chromatography; the estimated molecular mass was 100 kDa. The mutant GA exhibited optimum activity at pH 4.5 and an optimum temperature of 65 A degrees C.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Production and Characterization of β-glucosidase Obtained by the Solid-State Cultivation of the Thermophilic Fungus Thermomucor indicae-seudaticae N31

In this paper, several agro-industrial wastes (soybean meal and wheat straw, rice and peanut husks, corn cob and corn stover, and sugarcane bagasse) were tested for the production of β-glucosidase by the cultivation of thermophilic fungus Thermomucor indicae-seudaticae N31 in solid-state fermentation (SSF). Among the tested substrates, the highest yields were obtained in soybean meal. Other fermentation parameters were also evaluated, such as initial pH, merge substrates, and fermentation time, as well as the physicochemical characterization of the enzyme. The best results were obtained after 192 h of fermentation with the initial pH adjusted to 6.0. The substrate mixture did not improve the enzyme production by microorganism. The β-glucosidase showed best catalytic activity at pH 4.5 and at 75 °C and remained stable in the pH range from 4.5 to 9.5 and the temperature range 40–75 °C. The enzyme showed 80 % of its activity at a concentration of 15 mM glucose and remained stable up to 20 % ethanol.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq