Roberto da Silva

Production of xylanase and CMCase on solid state fermentation in different residues by Thermoascus aurantiacus miehe

The use of waste as raw material is important for government economy and natural balance. The purpose of this work was to study the production of CMCase and xylanase by a Brazilian strain of Thermoascus aurantiacus in solid state fermentation (SSF) using different agricultural residues (wheat bran, sugarcane bagasse, orange bagasse, corncob, green grass, dried grass, sawdust and corn straw) as substrates without enrichment of the medium and characterize the crude enzymes.The study of the extracellular cellulolytic and hemicellulolytic enzymes showed that T. arantiacus is more xylanolytic than cellulolytic. The highest levels of enzymes were produced in corncob, grasses and corn straw. All the enzymes were stable at room temperature by 24 h over a broad pH range (3.0-9.0) and also were stable at 60oC for 1 h. The optimum pH and temperature for xylanase and CMCase were 5.0-5.5 and 5.0 and 75oC, respectively. The microorganism grew quickly in stationary, simple and low cost medium. The secreted extracellular enzymes presented properties that match with those frequently required in industrial environment.

Pectinase production by Penicillium viridicatum RFC3 by solid state fermentation using agricultural wastes and agro-industrial by-products

Pectin lyase and polygalacturonase production by newly isolated Penicillium viridicatum strain Rfc3 was carried out by means of solid state fermentation using orange bagasse, corn tegument, wheat bran and mango and banana peels as carbon sources. The maximal activity value of polygalacturonase (Pg) (30U.g -1 ) was obtained using wheat bran as carbon source while maximal pectin lyase (Pl) (2000 U.g -1 ) activity value was obtained in medium composed of orange bagasse. Mixtures of banana or mango peels with sugar cane bagasse resulted in increased Pg and Pl production compared to fermentations in which this residue was not used. The mixture of orange bagasse and wheat bran (50%) increased the production of Pg and Pl to 55 U.g -1 and 3540 U.g –1 respectively. Fractions of Pg and Pl, isolated by gel filtration in Sephadex G50, presented optimum activity at pH 5.0 and 10.5 respectively. Maximal activity of Pg and Pl fractions was determined at 55oC and 50oC respectively. Pg was stable in neutral pH range and at 40oC whereas Pl was stable in acidic pH and at 35oC, for 1 h.

Screening of bacterial strains for pectinolytic activity: characterization of the polygalacturonase produced by Bacillus sp

One hundred sixty eight bacterial strains, isolated from soil and samples of vegetable in decomposition, were screened for the use of citrus pectin as the sole carbon source. 102 were positive for pectinase depolymerization in assay plates as evidenced by clear hydrolization halos. Among them, 30% presented considerable pectinolytic activity. The cultivation of these strains by submerged and semi-solid fermentation for polygalacturonase production indicated that five strains of Bacillus sp produced high quantities of the enzyme. The physico-chemical characteristics, such as optimum pH of 6.0 - 7.0, optimum temperatures between 45oC and 55oC, stability at temperatures above 40oC and in neutral and alkaline pH, were determined.

Pectinase production by fungal strains in solid-state fermentation using agro-industrial bioproduct

Pectin lyase and polygalacturonase production by newly isolated fungal strains was carried out in solid-state fermentation. Moniliella SB9 and Penicillium sp EGC5 produced polygalcturonase (PG) and pectin lyase (PL) on mixture of orange bagasse, sugar cane bagasse and wheat bran as substrate. PG and PL produced by Moniliella presented optimum activity at pH 4.5 and 10.0 and at 55 and 45°C, respectively, while these enzymes from Penicillium sp presented optimum activity at pH 4.5-5.0 and 9.0 and 40°C, respectively.

Enzimas termoestáveis: fontes, produção e aplicação industrial

REVIEW: Living organisms encountered in hostile environments that are characterized by extreme temperatures rely on novel molecular mechanisms to enhance the thermal stability of their proteins, nucleic acids, lipids and cell membranes. Proteins isolated from thermophilic organisms usually exhibit higher intrinsic thermal stabilities than their counterparts isolated from mesophilic organisms. Although the molecular basis of protein thermostability is only partially understood, structural studies have suggested that the factors that may contribute to enhance protein thermostability mainly include hydrophobic packing, enhanced secondary structure propensity, helix dipole stabilization, absence of residues sensitive to oxidation or deamination, and increased electrostatic interactions. Thermostable enzymes such as amylases, xylanases and pectinases isolated from thermophilic organisms are potentially of interest in the optimization of industrial processes due to their enhanced stability. In the present review, an attempt is made to delineate the structural factors that increase enzyme thermostability and to document the research results in the production of these enzymes.

Selection of thermophilic and thermotolerant fungi for the production of cellulases and xylanases under solid-state fermentation

Twenty-seven thermophilic and thermotolerant fungal strains were isolated from soil, decaying organic matter and sugarcane piles based on their ability to grow at 45°C on medium containing corn straw and cardboard as carbon sources. These fungi were identified in the genera Aspergillus, Thermomyces, Myceliophthora, Thermomucor and Candida. The majority of the isolated strains produced xylanase and cellulases under solid state fermentation (SSF). The highest cellulase and xylanase productions were obtained by the cultivation of the strains identified as Aspergillus fumigatus M.7.1 and Myceliophthora thermophila M.7.7. The enzymes from these strains exhibited maximum activity at pH 5.0 and at 60 and 70oC. The endo-glucanase from A. fumigatus was stable from 40°C to 65°C and both endo-glucanase and xylanase from M. thermophila were stable in this temperature range when in absence of substrate. The enzymes were stable from pH 4.0 to 9.0.

Evaluation of microwave-assisted pretreatment of lignocellulosic biomass immersed in alkaline glycerol for fermentable sugars production

A pretreatment with microwave irradiation was applied to enhance enzyme hydrolysis of corn straw and rice husk immersed in water, aqueous glycerol or alkaline glycerol. Native and pretreated solids underwent enzyme hydrolysis using the extract obtained from the fermentation of Myceliophthora heterothallica, comparing its efficiency with that of the commercial cellulose cocktail Celluclast®. The highest saccharification yields, for both corn straw and rice husk, were attained when biomass was pretreated in alkaline glycerol, method that has not been previously reported in literature. Moreover, FTIR, TG and SEM analysis revealed a more significant modification in the structure of corn straw subjected to this pretreatment. Highest global yields were attained with the crude enzyme extract, which might be the result of its content in a great variety of hydrolytic enzymes, as revealed zymogram analysis. Moreover, its hydrolysis efficiency can be improved by its supplementation with commercial β-glucosidase.

Produção de geléia de jambolão (Syzygium cumini Lamarck): processamento, parâmetros físico - químicos e avaliação sensorial

Universidade Estadual Paulista Programa de Pos-graduacao em Engenharia e Ciencia de Alimentos

Ligninases production by Basidiomycetes strains on lignocellulosic agricultural residues and their application in the decolorization of synthetic dyes

Wood rotting Basidiomycetes collected in the “Estação Ecológica do Noroeste Paulista”, São José do Rio Preto, São Paulo State, Brazil, concerning Aphyllophorales order and identified as Coriolopsis byrsina SXS16, Lentinus strigellus SXS355, Lentinus sp SXS48, Picnoporus sanguineus SXS 43 and Phellinus rimosus SXS47 were tested for ligninases production by solid state fermentation (SSF) using wheat bran or rice straw as culture media. C. byrsina produced the highest laccase (200 U mL-1) and Lentinus sp produced the highest activities of manganese peroxidase (MnP) and lignin peroxidase (LiP) (7 and 8 U mL-1, respectively), when cultivated on wheat bran. The effect of N addition on enzyme production was studied in medium containing rice straw and the data showed an increase of 3 up to 4-fold in the laccase production compared to that obtained in SSF on wheat bran. The laccases presented optimum pH at 3.0-3.5 and were stable at neutral pH values. Optimum pH for MnP and LiP activities was at 3.5 and between 4.5 and 6.0, respectively. All the strains produced laccase with optimum activities between 55-60ºC while the peroxidases presented maximum activity at temperatures of 30 to 55ºC. The crude enzymes promoted decolorization of chemically different dyes with around 70% of decolorization of RBBR and cybacron blue 3GA in 6h of treatment. The data indicated that enzymes from these basidiomycetes strains are able to decolorize synthetic dyes.

Evaluation of thermal stress indexes for dairy cows in tropical regions

Data from 359 Holstein and 54 Jersey cows (total of 1359 observations) collected in commercial herds in the northeast of Brazil were used to evaluate six environmental stress indexes. The selection criterion was the correlation between the index value with the rectal temperature (RT) and the respiratory rate (RR) of cows. Both Temperature-Humidity Index (THI) and Black Globe-Humidity Index (BGHI) had the lowest correlations with animal RT and RR. The selected indexes were the Equivalent Temperature Index (r = 0.293 and 0.520 with RT and RR, respectively) and the Heat Load Index (0.286 and 0.542, respectively).