Elisa Esposito

Screening of lignin-degrading fungi for removal of color from Kraft mill wastewater with no additional extra carbon-source

A screening of 51 ligninolytic strains of fungi to examine their ability to decolorized phenolic industrial effluent was carried out. The selection showed thatLentinus edodes (UEC-2019) strain removed 73% of colour in 5 days, without any additional carbon sources. Under these conditions,L. edodes was more efficient than the knownPhanerochaete chrysosporium (BKM-F-1767) strain (e.g. COD reductions were 60% and 26%, respectively).

Biodegradation of the herbicide diuron in soil by indigenous actinomycetes

Three actinomycete strains isolated from soil treated with 2,4-D were able to degrade the herbicide Diuron in vitro. Strain CCT 4916 was the most efficient, degrading up to 37% of applied Diuron (100 mg Kg-1 soil) in 7 days, as measured by HPLC and UV/VIS spectroscopy. All strains showed protease and urease activity; intracellular activity of metapyrocatechase and pyrocatechase were not found. Actinomycete strain CCT 4916 produced manganese peroxidase, which could be potentially related to degradation of Diuron.

Systematics and Environmental Application of the Genus Trichoderma

Trichoderma, an anamorphic Hypocreaceae (class Ascomycetes), is common in the environment, especially in soils. Species of this genus have been used in the production of cellulolytic and hemicellulolytic enzymes, biological control of plant disease, biodegradation of chlorophenolic compounds, and soil bioremediation. They are also the cause of disease in commercially produced mushrooms. The species Trichoderma has not been clearly defined yet, despite being a very common fungus with an expanding number of applications. Therefore, we highlight the importance of the use of molecular techninques along with conventional methodologies based on morphological characters in order to achieve a natural taxonomic system for this group of fungi, as well as for any other complex group of fungi.

Lignin biodegradation by the ascomycete Chrysonilia sitophila

The lignin biodegradation process has an important role in the carbon cycle of the biosphere. The study of this natural process has developed mainly with the use of basidiomycetes in laboratory investigations. This has been a logical approach since most of the microorganisms involved in lignocellulosic degradation belong to this class of fungi. However, other microorganisms such as ascomycetes and also some bacteria, are involved in the lignin decaying process. This work focuses on lignin biodegradation by a microorganism belonging to the ascomycete class,Chrysonilia sitophila. Lignin peroxidase production and characterization, mechanisms of lignin degradation (lignin model compounds and lignin in wood matrix) and biosynthesis of veratryl alcohol are outstanding. Applications of C.sitophila for effluent treatment, wood biodegradation and single-cell protein production are also discussed.

The use of principal component analysis (PCA) for pattern recognition in Eucalyptus grandis wood biodegradation experiments

Eucalyptus grandis wood was biodegraded by eight basidiomycetes and two ascomycetes. Four groups of decayed wood samples were recognized based on the principal component analysis (PCA) of weight and component loss data. Among the 10 fungal species studied, no selective lignin biodegradation was achieved. PCA was very efficient in recognizing wood decay patterns and seems to be a useful tool to analyse large group of weight- and component-loss data.

Phenoloxidases and hydrolases from Pycnoporus sanguineus (UEC-2050 strain): applications

Abstract The basidiomycete, Pycnoporus sanguineus , possess lignin peroxidase, Mn-peroxidase, phenoloxidases, xylanase and β-glucosidase activities when grown on malt extract. A large induction, mainly in laccase activity with malt extract/E 1 effluent (46 U l −1 ), malt extract (100 U l −1 ) and malt extract/ Eucalyptus grandis wood (61 U l −1 ) as carbon sources was found. The phenoloxidase capacity along with the presence of beta-glucosidase P. sanguineus led us investigate its use in effluent treatment. This fungus was efficient not only in chromophore group transformations but also in the reduction of phenols, biochemical and chemical oxygen demands, and toxicity.

Lignin peroxidase from Chrysonilia sitophila: Heat-denaturation kinetics and pH stability

Many practical applications utilizing lignin peroxidases from Chrysonilia sitophila (TFB-27441 strain) have been proposed. However, more information regarding the stability of these enzymes was required to design and develop these technologies. Heat- and pH-denaturation studies were conducted on purified lignin peroxidase and on crude culture of lignin peroxidase from C. sitophila. The culture produced in a 15-l bioreactor with Fries medium was utilized to obtain purified lignin peroxidases. LIG-I, LIG-II, and LIG-III were tested in the range 28–50°C, and LIG-III was found to be the most stable in the temperature range tested. The observed kD values at 28, 35, and 50°C were 0.058, 0.095, and 0.111 h−1, respectively. Increasing the LIG-III concentration by 2.3-fold increased thermal stability by around twofold. The heat-denaturation kinetics under these conditions for all lignin peroxidases and for the crude culture were first-order. LIG-I and LIG-II appeared as the most representative enzymes in the crude culture, since similar kD values were obtained. The pH stability showed the same trends.

Biomass photochemistry-XXII: Combined photochemical and biological process for treatment of Kraft El effluent

Abstract The photocatalytic conditions for decontamination of Kraft effluents from Eucalyptus grandis (Brazil) and Pinus radiata (Chile) were studied. Irradiation in the presence of ZnO was similar for E. grandis and P. radiata effluents reaching a total decolorization after 2 h. This correlates with the mineralization process. When ZnO was immobilized on sand a two-fold faster decolorization was observed after 30 min of irradiation. The combined photochemical-biobleaching process was effective in the decolorization of Eucalyptus Kraft El effluent. By applying a short time of irradiation (10 min) the time necessary for 50% of biological colour reduction was decreased to half. The contribution of the photochemical process when applied as a post-treatment was least evident. In this case additional reduction of about 10% on the AOX content and almost completion of the decolorization process was observed for Pinus Kraft El effluent. Photochemistry applied to pulp and paper industry appeared as an important technique to remediate pollution problems.

A new alternative process for Kraft E1 effluent treatment

Lentinus edodes (UEC-2019 strain) was selected after screening 51 ligninolytic strains of fungi for their ability to decolorize phenolic industrial effluent with high content of lignin peroxidases, Mn-peroxidases and beta-glucosidases. This strain removed 73 % of color in theEucalyptus Kraft E1 effluent in 5 days without any additional carbon sources. A 13% mycelial adsorption was found. Correlation between mass loss, COD, TOC and decolorization was observed. When an effluent pre-irradiated (10 min) in the presence of ZnO was treated withL. edodes, a marked enhancement of the decolorization at 48 h was obtained.L. edodes is an active fungus in this pre-treatment and biobleaching process. The combined photo-biological decolorization procedure appears to be an efficient decontamination method with great potential in industrial effluent treatment.

Remediação de efluentes derivados da indústria de papel e celulose: tratamento biológico e fotocatalítico

The contribution of the industrial activities to the environmental contamination phenomena is evident. Great efforts are dedicated to the establishment of methodologies which permits an adequate treatment of the produced effluents, as a manner of minimizing the environmental impact of these wastes. The methodologies based on photocatalytic processes are very promise alternatives, because permits degradation of a great number of chemical substances of high toxic potential, without the use of other chemicals. The present work is an overview about the principal environmental aspects related with the paper and cellulose industry and the main alternatives employed for the reduction of environmental impact produced for its residues. The principal results of the photocatalytic treatment of this kind of effluents using metallic semiconductors is also showed.